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class=breadcrumbs__item><span class=breadcrumbs__link>Guide</span><li class=breadcrumbs__item><a class=breadcrumbs__link href=/docs/guide/python/><span>Python</span></a><li class="breadcrumbs__item breadcrumbs__item--active"><span class=breadcrumbs__link>Schema Metadata</span></ul></nav><span class="theme-doc-version-badge badge badge--secondary">Version: 1.3.0</span><div class="tocCollapsible_ETCw theme-doc-toc-mobile tocMobile_ITEo"><button type=button class="clean-btn tocCollapsibleButton_TO0P">On this page</button></div><div class="theme-doc-markdown markdown"><header><h1>Schema Metadata</h1></header><p>This page explains how to configure field-level metadata for serialization in Python.</p> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=overview>Overview<a href=#overview class=hash-link aria-label="Direct link to Overview" title="Direct link to Overview" translate=no></a></h2> |
| <p>Apache Fory™ provides field-level configuration through:</p> |
| <ul> |
| <li class=""><strong><code>pyfory.field()</code></strong>: Configure field metadata (id, nullable, ref, ignore, dynamic)</li> |
| <li class=""><strong>Type annotations</strong>: Control integer encoding (varint, fixed, tagged)</li> |
| <li class=""><strong><code>Optional[T]</code></strong>: Mark fields as nullable</li> |
| </ul> |
| <p>This enables:</p> |
| <ul> |
| <li class=""><strong>Tag IDs</strong>: Assign compact numeric IDs to reduce struct field meta size overhead</li> |
| <li class=""><strong>Nullability</strong>: Control whether fields can be null</li> |
| <li class=""><strong>Reference Tracking</strong>: Enable reference tracking for shared objects</li> |
| <li class=""><strong>Field Skipping</strong>: Exclude fields from serialization</li> |
| <li class=""><strong>Encoding Control</strong>: Specify how integers are encoded (varint, fixed, tagged)</li> |
| <li class=""><strong>Polymorphism</strong>: Control whether type info is written for struct fields</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=basic-syntax>Basic Syntax<a href=#basic-syntax class=hash-link aria-label="Direct link to Basic Syntax" title="Direct link to Basic Syntax" translate=no></a></h2> |
| <p>Use <code>@dataclass</code> decorator with type annotations and <code>pyfory.field()</code>:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> dataclasses </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> dataclass</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> typing </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> Optional</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> pyfory</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Person</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> age</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> nickname</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=the-pyforyfield-function>The <code>pyfory.field()</code> Function<a href=#the-pyforyfield-function class=hash-link aria-label="Direct link to the-pyforyfield-function" title="Direct link to the-pyforyfield-function" translate=no></a></h2> |
| <p>Use <code>pyfory.field()</code> to configure field-level metadata:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">User</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> email</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> friends</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>[</span><span class="token string" style=color:#e3116c>"User"</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>3</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">list</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> _cache</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">dict</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">ignore</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">dict</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=parameters>Parameters<a href=#parameters class=hash-link aria-label="Direct link to Parameters" title="Direct link to Parameters" translate=no></a></h3> |
| <table><thead><tr><th>Parameter<th>Type<th>Default<th>Description<tbody><tr><td><code>id</code><td><code>int</code><td>omitted<td>Non-negative field tag ID<tr><td><code>nullable</code><td><code>bool</code><td><code>False</code><td>Whether the field can be null<tr><td><code>ref</code><td><code>bool</code><td><code>False</code><td>Enable reference tracking<tr><td><code>ignore</code><td><code>bool</code><td><code>False</code><td>Exclude field from serialization<tr><td><code>dynamic</code><td><code>bool</code><td><code>None</code><td>Control whether type info is written<tr><td><code>default</code><td>Any<td><code>MISSING</code><td>Default value for the field<tr><td><code>default_factory</code><td>Callable<td><code>MISSING</code><td>Factory function for default value</table> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=field-id-id>Field ID (<code>id</code>)<a href=#field-id-id class=hash-link aria-label="Direct link to field-id-id" title="Direct link to field-id-id" translate=no></a></h2> |
| <p>Assigns a numeric ID to a field to minimize struct field meta size overhead:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">User</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> age</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <p><strong>Benefits</strong>:</p> |
| <ul> |
| <li class="">Smaller serialized size (numeric IDs vs field names in metadata)</li> |
| <li class="">Reduced struct field meta overhead</li> |
| <li class="">Allows renaming fields without breaking binary compatibility</li> |
| </ul> |
| <p><strong>Recommendation</strong>: It is recommended to configure field IDs for compatible mode since it reduces serialization cost.</p> |
| <p><strong>Notes</strong>:</p> |
| <ul> |
| <li class="">IDs must be unique within a class</li> |
| <li class="">IDs must be >= 0</li> |
| <li class="">If not specified, field name is used in metadata (larger overhead)</li> |
| </ul> |
| <p><strong>Without field IDs</strong> (field names used in metadata):</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">User</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>""</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=nullable-fields-nullable>Nullable Fields (<code>nullable</code>)<a href=#nullable-fields-nullable class=hash-link aria-label="Direct link to nullable-fields-nullable" title="Direct link to nullable-fields-nullable" translate=no></a></h2> |
| <p>Use <code>nullable=True</code> for fields that can be <code>None</code>:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> typing </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> Optional</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Record</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Nullable string field</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> optional_name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Nullable integer field</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> optional_count</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int32</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <p><strong>Notes</strong>:</p> |
| <ul> |
| <li class=""><code>Optional[T]</code> fields must have <code>nullable=True</code></li> |
| <li class="">Non-optional fields default to <code>nullable=False</code></li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=reference-tracking-ref>Reference Tracking (<code>ref</code>)<a href=#reference-tracking-ref class=hash-link aria-label="Direct link to reference-tracking-ref" title="Direct link to reference-tracking-ref" translate=no></a></h2> |
| <p>Enable reference tracking for fields that may be shared. Circular Python object |
| graphs require Python native mode with global reference tracking enabled.</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">RefOuter</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Both fields may point to the same inner object</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> inner1</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">RefInner</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> inner2</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">RefInner</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">CircularRef</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Self-referencing field for circular references</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> self_ref</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token string" style=color:#e3116c>"CircularRef"</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <p><strong>Use Cases</strong>:</p> |
| <ul> |
| <li class="">Enable for fields that may be circular or shared</li> |
| <li class="">When the same object is referenced from multiple fields</li> |
| </ul> |
| <p><strong>Notes</strong>:</p> |
| <ul> |
| <li class="">Global <code>Fory(ref=True)</code> must be enabled.</li> |
| <li class="">Field-level <code>ref=True</code> and global <code>ref=True</code> must both be enabled for schema |
| fields.</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=skipping-fields-ignore>Skipping Fields (<code>ignore</code>)<a href=#skipping-fields-ignore class=hash-link aria-label="Direct link to skipping-fields-ignore" title="Direct link to skipping-fields-ignore" translate=no></a></h2> |
| <p>Exclude fields from serialization:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">User</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Not serialized</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> _cache</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">dict</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">ignore</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">dict</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> _internal_state</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">ignore</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=dynamic-fields-dynamic>Dynamic Fields (<code>dynamic</code>)<a href=#dynamic-fields-dynamic class=hash-link aria-label="Direct link to dynamic-fields-dynamic" title="Direct link to dynamic-fields-dynamic" translate=no></a></h2> |
| <p>Control whether type information is written for struct fields. This is essential for polymorphism support:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> abc </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> ABC</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> abstractmethod</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Shape</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">ABC</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token decorator annotation punctuation" style=color:#393A34>@abstractmethod</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>def</span><span class="token plain"> </span><span class="token function" style=color:#d73a49>area</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">self</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>-</span><span class="token operator" style=color:#393A34>></span><span class="token plain"> </span><span class="token builtin">float</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>pass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Circle</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">Shape</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> radius</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">float</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0.0</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>def</span><span class="token plain"> </span><span class="token function" style=color:#d73a49>area</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">self</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>-</span><span class="token operator" style=color:#393A34>></span><span class="token plain"> </span><span class="token builtin">float</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>return</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>3.14159</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>*</span><span class="token plain"> self</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">radius </span><span class="token operator" style=color:#393A34>*</span><span class="token plain"> self</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">radius</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Container</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Abstract class: dynamic is always True (type info written)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> shape</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Shape </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Force type info for concrete type (support subtypes)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> circle</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Circle </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> dynamic</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Skip type info for concrete type (use declared type directly)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> fixed_circle</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Circle </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> dynamic</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>False</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <p><strong>Default Behavior</strong>:</p> |
| <table><thead><tr><th>Mode<th>Abstract Class<th>Concrete Object Types<th>Numeric/str/time Types<tbody><tr><td>Native mode<td><code>True</code><td><code>True</code><td><code>False</code><tr><td>Xlang mode<td><code>True</code><td><code>False</code><td><code>False</code></table> |
| <p><strong>Notes</strong>:</p> |
| <ul> |
| <li class=""><strong>Abstract classes</strong>: <code>dynamic</code> is always <code>True</code> (type info must be written)</li> |
| <li class=""><strong>Native mode</strong>: <code>dynamic</code> defaults to <code>True</code> for object types, <code>False</code> for numeric/str/time types</li> |
| <li class=""><strong>Xlang mode</strong>: <code>dynamic</code> defaults to <code>False</code> for concrete types</li> |
| <li class="">Use <code>dynamic=True</code> when a concrete field may hold subclass instances</li> |
| <li class="">Use <code>dynamic=False</code> for performance optimization when type is known</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=integer-type-annotations>Integer Type Annotations<a href=#integer-type-annotations class=hash-link aria-label="Direct link to Integer Type Annotations" title="Direct link to Integer Type Annotations" translate=no></a></h2> |
| <p>Fory provides type annotations to control integer encoding:</p> |
| <p>Use these markers directly in Python type annotations. Field values remain |
| ordinary Python <code>int</code> or <code>float</code> values, and Fory serializes them with the |
| requested xlang numeric width and encoding.</p> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=signed-integers>Signed Integers<a href=#signed-integers class=hash-link aria-label="Direct link to Signed Integers" title="Direct link to Signed Integers" translate=no></a></h3> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">SignedIntegers</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> byte_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int8 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 8-bit signed</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> short_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int16 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 16-bit signed</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> int_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 32-bit signed (varint encoding)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> long_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 64-bit signed (varint encoding)</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=unsigned-integers>Unsigned Integers<a href=#unsigned-integers class=hash-link aria-label="Direct link to Unsigned Integers" title="Direct link to Unsigned Integers" translate=no></a></h3> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">UnsignedIntegers</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Fixed-size encoding</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u8_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">UInt8 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 8-bit unsigned (fixed)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u16_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">UInt16 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 16-bit unsigned (fixed)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Variable-length encoding (default for u32/u64)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u32_var</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">UInt32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 32-bit unsigned (varint)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u64_var</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">UInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 64-bit unsigned (varint)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Explicit fixed-size encoding</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u32_fixed</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">FixedUInt32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 32-bit unsigned (fixed 4 bytes)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u64_fixed</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">FixedUInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 64-bit unsigned (fixed 8 bytes)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Tagged encoding (includes type tag)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> u64_tagged</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">TaggedUInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 64-bit unsigned (tagged)</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=floating-point>Floating Point<a href=#floating-point class=hash-link aria-label="Direct link to Floating Point" title="Direct link to Floating Point" translate=no></a></h3> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">FloatingPoint</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> float_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Float32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0.0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 32-bit float</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> double_val</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Float64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0.0</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># 64-bit double</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=encoding-summary>Encoding Summary<a href=#encoding-summary class=hash-link aria-label="Direct link to Encoding Summary" title="Direct link to Encoding Summary" translate=no></a></h3> |
| <table><thead><tr><th>Type<th>Encoding<th>Size<tbody><tr><td><code>pyfory.Int8</code><td>fixed<td>1 byte<tr><td><code>pyfory.Int16</code><td>fixed<td>2 bytes<tr><td><code>pyfory.Int32</code><td>varint<td>1-5 bytes<tr><td><code>pyfory.Int64</code><td>varint<td>1-10 bytes<tr><td><code>pyfory.FixedInt32</code><td>fixed<td>4 bytes<tr><td><code>pyfory.FixedInt64</code><td>fixed<td>8 bytes<tr><td><code>pyfory.TaggedInt64</code><td>tagged<td>1-9 bytes<tr><td><code>pyfory.UInt8</code><td>fixed<td>1 byte<tr><td><code>pyfory.UInt16</code><td>fixed<td>2 bytes<tr><td><code>pyfory.UInt32</code><td>varint<td>1-5 bytes<tr><td><code>pyfory.UInt64</code><td>varint<td>1-10 bytes<tr><td><code>pyfory.FixedUInt32</code><td>fixed<td>4 bytes<tr><td><code>pyfory.FixedUInt64</code><td>fixed<td>8 bytes<tr><td><code>pyfory.TaggedUInt64</code><td>tagged<td>1-9 bytes<tr><td><code>pyfory.Float32</code><td>fixed<td>4 bytes<tr><td><code>pyfory.Float64</code><td>fixed<td>8 bytes</table> |
| <p><strong>When to Use</strong>:</p> |
| <ul> |
| <li class=""><code>varint</code>: Best for values that are often small (default for int32/int64/uint32/uint64)</li> |
| <li class=""><code>fixed</code>: Best for values that use full range (e.g., timestamps, hashes)</li> |
| <li class=""><code>tagged</code>: When type information needs to be preserved (int64/uint64 only)</li> |
| </ul> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=nested-container-type-annotations>Nested Container Type Annotations<a href=#nested-container-type-annotations class=hash-link aria-label="Direct link to Nested Container Type Annotations" title="Direct link to Nested Container Type Annotations" translate=no></a></h2> |
| <p>Integer encoding aliases can be used inside declared collection schemas. Fory uses the declared |
| field schema for every nested element, key, and value in both pure Python and Cython modes:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> dataclasses </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> dataclass</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> field</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> typing </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> Dict</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> List</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> pyfory</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Counters</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> values</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Dict</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">FixedInt32</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>[</span><span class="token plain">pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">TaggedInt64</span><span class="token punctuation" style=color:#393A34>]</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">dict</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <p>For <code>values</code>, map keys are written as fixed-width int32 values and each nested list element is |
| written as tagged int64. Runtime type inference is used only for dynamic or unknown container |
| schemas.</p> |
| <p>In compatible mode, readers consume field bytes using the remote schema metadata. Python assigns the |
| decoded value only when it can safely satisfy the local declared schema. Scalar conversion and |
| integer encoding adaptation apply only to the immediate matched field schema. Nested collection |
| elements, map keys, and map values must keep exact nullability, reference-tracking, and type shape |
| metadata, except for user-type family normalization such as named and unnamed struct metadata.</p> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=complete-example>Complete Example<a href=#complete-example class=hash-link aria-label="Direct link to Complete Example" title="Direct link to Complete Example" translate=no></a></h2> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> dataclasses </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> dataclass</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>from</span><span class="token plain"> typing </span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> Dict</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> Set</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>import</span><span class="token plain"> pyfory</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Document</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Fields with tag IDs (recommended for compatible mode)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> title</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> version</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Nullable field</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> description</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Collection fields</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> tags</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>3</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">list</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> metadata</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Dict</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>4</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">dict</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> categories</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Set</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>5</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">set</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Unsigned integers with different encodings</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> view_count</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">UInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>6</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># varint encoding</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> file_size</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">FixedUInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>7</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># fixed encoding</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> checksum</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">TaggedUInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>8</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># tagged encoding</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Reference-tracked field for shared/circular references</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> parent</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token string" style=color:#e3116c>"Document"</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>9</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Ignored field (not serialized)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> _cache</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">dict</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">ignore</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default_factory</span><span class="token operator" style=color:#393A34>=</span><span class="token builtin">dict</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>def</span><span class="token plain"> </span><span class="token function" style=color:#d73a49>main</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> fory </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Fory</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">xlang</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> fory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">register_type</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">Document</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> type_id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>100</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> doc </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> Document</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> title</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>"My Document"</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> version</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> description</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>"A sample document"</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> tags</span><span class="token operator" style=color:#393A34>=</span><span class="token punctuation" style=color:#393A34>[</span><span class="token string" style=color:#e3116c>"tag1"</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>"tag2"</span><span class="token punctuation" style=color:#393A34>]</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> metadata</span><span class="token operator" style=color:#393A34>=</span><span class="token punctuation" style=color:#393A34>{</span><span class="token string" style=color:#e3116c>"key"</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>"value"</span><span class="token punctuation" style=color:#393A34>}</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> categories</span><span class="token operator" style=color:#393A34>=</span><span class="token punctuation" style=color:#393A34>{</span><span class="token string" style=color:#e3116c>"cat1"</span><span class="token punctuation" style=color:#393A34>}</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> view_count</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>42</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> file_size</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1024</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> checksum</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>123456789</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> parent</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Serialize</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> data </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> fory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">serialize</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">doc</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Deserialize</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> decoded </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> fory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">deserialize</span><span class="token punctuation" style=color:#393A34>(</span><span class="token plain">data</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>assert</span><span class="token plain"> decoded</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">title </span><span class="token operator" style=color:#393A34>==</span><span class="token plain"> doc</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">title</span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token keyword" style=color:#00009f>assert</span><span class="token plain"> decoded</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">version </span><span class="token operator" style=color:#393A34>==</span><span class="token plain"> doc</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">version</span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>if</span><span class="token plain"> __name__ </span><span class="token operator" style=color:#393A34>==</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>"__main__"</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> main</span><span class="token punctuation" style=color:#393A34>(</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=cross-language-compatibility>Cross-Language Compatibility<a href=#cross-language-compatibility class=hash-link aria-label="Direct link to Cross-Language Compatibility" title="Direct link to Cross-Language Compatibility" translate=no></a></h2> |
| <p>When serializing data to be read by other languages (Java, Rust, C++, Go), use field IDs and matching type annotations:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">CrossLangData</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Use field IDs for cross-language compatibility</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> int_var</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int32 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> long_fixed</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">FixedUInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> long_tagged</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">TaggedUInt64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> optional_value</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>3</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=schema-evolution>Schema Evolution<a href=#schema-evolution class=hash-link aria-label="Direct link to Schema Evolution" title="Direct link to Schema Evolution" translate=no></a></h2> |
| <p>Compatible mode supports schema evolution. It is recommended to configure field IDs to reduce serialization cost:</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token comment" style=color:#999988;font-style:italic># Version 1</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">DataV1</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain" style=display:inline-block></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token comment" style=color:#999988;font-style:italic># Version 2: Added new field</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">DataV2</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> email</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># New field</span><br/></div></code></pre></div></div> |
| <p>Data serialized with V1 can be deserialized with V2 (new field will be <code>None</code>).</p> |
| <p>Alternatively, field IDs can be omitted (field names will be used in metadata with larger overhead):</p> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">Data</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>""</span><br/></div></code></pre></div></div> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=native-mode-vs-xlang-mode>Native Mode vs Xlang Mode<a href=#native-mode-vs-xlang-mode class=hash-link aria-label="Direct link to Native Mode vs Xlang Mode" title="Direct link to Native Mode vs Xlang Mode" translate=no></a></h2> |
| <p>Field configuration behaves differently depending on the serialization mode:</p> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=native-mode-python-only>Native Mode (Python-only)<a href=#native-mode-python-only class=hash-link aria-label="Direct link to Native Mode (Python-only)" title="Direct link to Native Mode (Python-only)" translate=no></a></h3> |
| <p>Native mode has <strong>relaxed default values</strong> for maximum compatibility:</p> |
| <ul> |
| <li class=""><strong>Nullable</strong>: <code>str</code> and numeric types are non-nullable by default unless <code>Optional</code> is used</li> |
| <li class=""><strong>Ref tracking</strong>: Enabled by default for object references (except <code>str</code> and numeric types)</li> |
| </ul> |
| <p>In native mode, you typically <strong>don't need to configure field annotations</strong> unless you want to:</p> |
| <ul> |
| <li class="">Reduce serialized size by using field IDs</li> |
| <li class="">Optimize performance by disabling unnecessary ref tracking</li> |
| </ul> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token comment" style=color:#999988;font-style:italic># Native mode: works without schema metadata</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">User</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">int</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token number" style=color:#36acaa>0</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token string" style=color:#e3116c>""</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> tags</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> List</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> </span><span class="token boolean" style=color:#36acaa>None</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=xlang-mode-cross-language>Xlang Mode (Cross-language)<a href=#xlang-mode-cross-language class=hash-link aria-label="Direct link to Xlang Mode (Cross-language)" title="Direct link to Xlang Mode (Cross-language)" translate=no></a></h3> |
| <p>Xlang mode has <strong>stricter default values</strong> due to type system differences between languages:</p> |
| <ul> |
| <li class=""><strong>Nullable</strong>: Fields are non-nullable by default (<code>nullable=False</code>)</li> |
| <li class=""><strong>Ref tracking</strong>: Disabled by default (<code>ref=False</code>)</li> |
| </ul> |
| <p>In xlang mode, you <strong>need to configure fields</strong> when:</p> |
| <ul> |
| <li class="">A field can be None (use <code>Optional[T]</code> with <code>nullable=True</code>)</li> |
| <li class="">A field needs reference tracking for shared/circular objects (use <code>ref=True</code>)</li> |
| <li class="">Integer types need specific encoding for cross-language compatibility</li> |
| <li class="">You want to reduce metadata size (use field IDs)</li> |
| </ul> |
| <div class="language-python codeBlockContainer_Ckt0 theme-code-block" style=--prism-color:#393A34;--prism-background-color:#f6f8fa><div class=codeBlockContent_QJqH><pre tabindex=0 class="prism-code language-python codeBlock_bY9V thin-scrollbar" style=color:#393A34;background-color:#f6f8fa><code class=codeBlockLines_e6Vv><div class=token-line style=color:#393A34><span class="token comment" style=color:#999988;font-style:italic># Xlang mode: explicit configuration required for nullable/ref fields</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token decorator annotation punctuation" style=color:#393A34>@dataclass</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"></span><span class="token keyword" style=color:#00009f>class</span><span class="token plain"> </span><span class="token class-name">User</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> </span><span class="token builtin">id</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">Int64 </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>0</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> name</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> </span><span class="token builtin">str</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>1</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token string" style=color:#e3116c>""</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> email</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token builtin">str</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>2</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Must declare nullable</span><span class="token plain"></span><br/></div><div class=token-line style=color:#393A34><span class="token plain"> friend</span><span class="token punctuation" style=color:#393A34>:</span><span class="token plain"> Optional</span><span class="token punctuation" style=color:#393A34>[</span><span class="token string" style=color:#e3116c>"User"</span><span class="token punctuation" style=color:#393A34>]</span><span class="token plain"> </span><span class="token operator" style=color:#393A34>=</span><span class="token plain"> pyfory</span><span class="token punctuation" style=color:#393A34>.</span><span class="token plain">field</span><span class="token punctuation" style=color:#393A34>(</span><span class="token builtin">id</span><span class="token operator" style=color:#393A34>=</span><span class="token number" style=color:#36acaa>3</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> ref</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> nullable</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>True</span><span class="token punctuation" style=color:#393A34>,</span><span class="token plain"> default</span><span class="token operator" style=color:#393A34>=</span><span class="token boolean" style=color:#36acaa>None</span><span class="token punctuation" style=color:#393A34>)</span><span class="token plain"> </span><span class="token comment" style=color:#999988;font-style:italic># Must declare ref</span><br/></div></code></pre></div></div> |
| <h3 class="anchor anchorTargetStickyNavbar_Vzrq" id=default-values-summary>Default Values Summary<a href=#default-values-summary class=hash-link aria-label="Direct link to Default Values Summary" title="Direct link to Default Values Summary" translate=no></a></h3> |
| <table><thead><tr><th>Option<th>Native Mode Default<th>Xlang Mode Default<tbody><tr><td><code>nullable</code><td><code>False</code> for <code>str</code>/numeric; others nullable by default<td><code>False</code><tr><td><code>ref</code><td><code>True</code> (except <code>str</code> and numeric types)<td><code>False</code><tr><td><code>dynamic</code><td><code>True</code> (except numeric/str/time types)<td><code>False</code> (concrete)</table> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=best-practices>Best Practices<a href=#best-practices class=hash-link aria-label="Direct link to Best Practices" title="Direct link to Best Practices" translate=no></a></h2> |
| <ol> |
| <li class=""><strong>Configure field IDs</strong>: Recommended for compatible mode to reduce serialization cost</li> |
| <li class=""><strong>Use <code>Optional[T]</code> with <code>nullable=True</code></strong>: Required for nullable fields in xlang mode</li> |
| <li class=""><strong>Enable ref tracking for shared objects</strong>: Use <code>ref=True</code> when objects are shared or circular</li> |
| <li class=""><strong>Use <code>ignore=True</code> for sensitive data</strong>: Passwords, tokens, internal state</li> |
| <li class=""><strong>Choose appropriate encoding</strong>: <code>varint</code> for small values, <code>fixed</code> for full-range values</li> |
| <li class=""><strong>Keep IDs stable</strong>: Once assigned, don't change field IDs</li> |
| </ol> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=options-reference>Options Reference<a href=#options-reference class=hash-link aria-label="Direct link to Options Reference" title="Direct link to Options Reference" translate=no></a></h2> |
| <table><thead><tr><th>Configuration<th>Description<tbody><tr><td><code>pyfory.field(id=N)</code><td>Field tag ID to reduce metadata size<tr><td><code>pyfory.field(nullable=True)</code><td>Mark field as nullable<tr><td><code>pyfory.field(ref=True)</code><td>Enable reference tracking<tr><td><code>pyfory.field(ignore=True)</code><td>Exclude field from serialization<tr><td><code>pyfory.field(dynamic=True)</code><td>Force type info to be written<tr><td><code>pyfory.field(dynamic=False)</code><td>Skip type info (use declared type)<tr><td><code>Optional[T]</code><td>Type hint for nullable fields<tr><td><code>pyfory.Int32</code>, <code>pyfory.Int64</code><td>Signed integers (varint encoding)<tr><td><code>pyfory.FixedInt32</code>, <code>pyfory.FixedInt64</code><td>Fixed-size signed<tr><td><code>pyfory.TaggedInt64</code><td>Tagged encoding for int64<tr><td><code>pyfory.UInt32</code>, <code>pyfory.UInt64</code><td>Unsigned integers (varint encoding)<tr><td><code>pyfory.FixedUInt32</code>, <code>pyfory.FixedUInt64</code><td>Fixed-size unsigned<tr><td><code>pyfory.TaggedUInt64</code><td>Tagged encoding for uint64</table> |
| <h2 class="anchor anchorTargetStickyNavbar_Vzrq" id=related-topics>Related Topics<a href=#related-topics class=hash-link aria-label="Direct link to Related Topics" title="Direct link to Related Topics" translate=no></a></h2> |
| <ul> |
| <li class=""><a class="" href=/docs/guide/python/basic_serialization>Basic Serialization</a> - Getting started with Fory serialization</li> |
| <li class=""><a class="" href=/docs/guide/python/schema_evolution>Schema Evolution</a> - Compatible mode and schema evolution</li> |
| <li class=""><a class="" href=/docs/guide/python/xlang_serialization>Xlang Serialization</a> - Interoperability with Java, Rust, C++, Go</li> |
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