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| <h1 class="content-header header-section1" id="versions_2_0RC1" itemprop="headline">2.0 RC1</h1> |
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| <div class="page-menu-title">Page Contents</div> |
| <ul><li><a class="page-menu-link" href="#autoid_238" data-menu-target="autoid_238">Support for Numerical operations, both arithmetic and |
| boolean, as well as numerical ranges.</a></li><li><a class="page-menu-link" href="#autoid_239" data-menu-target="autoid_239">API Changes</a></li><li><a class="page-menu-link" href="#autoid_240" data-menu-target="autoid_240">Syntactical Miscellany</a></li></ul> </div><p>The first public release of FreeMarker 2.0 was on 18 March 2002. |
| Here is a summary of the changes in the Lazarus release, with respect |
| to the last stable release of FreeMarker Classic.</p><p><em>NOTA BENE</em>:</p><p>Despite the changes delineated above, the Lazarus release is |
| almost entirely backward-compatible with FreeMarker Classic. We |
| believe that <em>most</em> existing code and templates |
| that work under FreeMarker Classic will continue working under |
| Lazarus, with at most minimal changes. In practice, the most common |
| cases where legacy template code is broken will be where assumptions |
| were made about numbers and strings being equivalent. Note that in |
| FreeMarker 2, 2 + 2 does not result in "22". The String "1" and the |
| number 1 are entirely different animals and thus, any code will be |
| broken if it relies on the boolean expression ("1"==1) being true. |
| There is a "classic compatibility mode" that can be set via: |
| <code class="inline-code">Template.setClassCompatibility()</code> that can be set so |
| that Lazarus emulates some of the quirky behavior of FreeMarker |
| Classic. However, any code that relied on the above "features" of |
| FreeMarker classic really should be reworked. You are less likely to |
| run into the other incompatibilities that are listed above. If you |
| come across any other anomalies, please do tell us about them.</p> |
| |
| |
| |
| |
| <h2 class="content-header header-section2" id="autoid_238">Support for Numerical operations, both arithmetic and |
| boolean, as well as numerical ranges.</h2> |
| |
| |
| <ul> |
| <li> |
| <p>Scalars can now be either strings or numbers. (In |
| FreeMarker Classic all scalars were strings.) The basic |
| operations allowed are addition, subtraction, multiplication, |
| division, and modulus using the <code class="inline-code">+</code>, |
| <code class="inline-code">-</code>, <code class="inline-code">*</code>, |
| <code class="inline-code">/</code>, and <code class="inline-code">%</code> operators |
| respectively. Arbitrary-precision arithmetic with integers and |
| floating point numbers are provided. Though our goal is |
| definitely to follow the principle of least surprise, for |
| backward compatibility, the <code class="inline-code">+</code> operator still |
| is used for string concatenation. If either the left hand side |
| or the right hand side of <code class="inline-code">lhs + rhs</code> is |
| non-numerical, we revert to interpreting this as string |
| concatenation. Thus, in FreeMarker 2, 2+2 evaluates to the |
| number 4, while any of "2"+2 or 2+"2" or "2"+"2" evaluate to the |
| string "22". In FreeMarker Classic, rather embarrassingly, all |
| of the above, including 2+2, evaluated to the string "22". An |
| attempt to use any other arithmetic operator besides the |
| <code class="inline-code">+</code> with non-numerical operands will cause an |
| exception to be thrown.</p> |
| </li> |
| |
| <li> |
| <p>Output of a numerical expression can be made explicit via |
| the alternative <code class="inline-code">#{....}</code> syntax. If the |
| expression within the curly parentheses does not evaluate to a |
| numerical value, an exception is thrown. The older ${....} |
| syntax can evaluate to either a number or a string. In general, |
| if, for logical reasons, the output <em>must</em> be |
| numerical, it is preferable to use the #{...} syntax, since it |
| adds an extra sanity check. Note that if, by some miracle, the |
| character sequence "#{" occurs in your template, you will have |
| to use a workaround to prevent problems. (The <noparse> |
| directive is one possibility.)</p> |
| </li> |
| |
| <li> |
| <p>In this release, there is a facility for specifying the |
| number of digits to show after the decimal point. The following |
| code specifies to show at least 3 digits after the decimal point |
| but not more than 6. This is optional. This option is only |
| available if you use the #{...} syntax.</p> |
| |
| |
| |
| <div class="code-wrapper"><pre class="code-block code-template">#{foo + bar ; m3M6} </pre></div> |
| |
| <p>(Note that the above is something of a stopgap measure. |
| Future releases will move toward supporting fully |
| internationalization and localization of number and currency |
| formatting.</p> |
| </li> |
| |
| <li> |
| <p>Numerical expressions can be used in boolean expressions |
| via the comparison operators: <code class="inline-code">lt</code>, |
| <code class="inline-code">gt</code>, <code class="inline-code">lte</code>, and |
| <code class="inline-code">gte</code>. In the web space, where FreeMarker is |
| most used in practice, using the more natural operators such as |
| < and > would tend to confuse HTML-oriented editors. An |
| attempt to compare non-numerical expressions using these |
| operators leads to a <code class="inline-code">TemplateException</code> being |
| thrown. If, by some coincidence, you have variables named "lt", |
| "gt", "lte", or "gte", you will have to change their names, |
| since they are now keywords in the language.</p> |
| </li> |
| |
| <li> |
| <p>Numerical ranges are supported.</p> |
| |
| |
| |
| <div class="code-wrapper"><pre class="code-block code-template"><#list 1990..2001 as year> |
| blah blah in the year ${year} blah |
| </#list> </pre></div> |
| |
| <p>The left hand and right hand sides of the |
| <code class="inline-code">..</code> operator must be numerical, or an |
| exception is thrown. They also need not be literal numbers, but |
| can be more complex expressions that evaluate to a numerical |
| scalar value. Note that it is also possible to write a range |
| that descends in value:</p> |
| |
| |
| |
| <div class="code-wrapper"><pre class="code-block code-template"><#list 2001..1990 as year> |
| blah blah in the year ${year} blah blah |
| </#list> </pre></div> |
| </li> |
| </ul> |
| |
| |
| |
| |
| |
| <h2 class="content-header header-section2" id="autoid_239">API Changes</h2> |
| |
| |
| <ul> |
| <li> |
| <p>The <code class="inline-code">TemplateNumberModel</code> interface and |
| the <code class="inline-code">SimpleNumber</code> implementation were added to |
| support exposing numerical values.</p> |
| </li> |
| |
| <li> |
| <p>The <code class="inline-code">TemplateListModel</code> API in FreeMarker |
| Classic had some design problems -- particularly in terms of |
| supporting thread-safe code. It has been deprecated in favor of |
| the following API's: <code class="inline-code">TemplateCollectionModel</code> |
| and <code class="inline-code">TemplateSequenceModel</code>. The |
| <code class="inline-code">SimpleList</code> class was refactored to implement |
| the above interfaces (and paradoxically, does not implement the |
| TemplateListModel interface.) Code that uses the deprecated |
| <code class="inline-code">TemplateListModel</code> should be |
| refactored.</p> |
| </li> |
| |
| <li> |
| <p>The Expose Package by Attila Szegedi has been made an |
| integral part of the FreeMarker distribution and is now under |
| the freemarker.ext.* hierarchy. This package provides advanced |
| models for representing arbitrary Java objects as template |
| models, for representing XML documents as template models, as |
| well as classes to facilitate the integration of FreeMarker with |
| servlets and Ant.</p> |
| </li> |
| |
| <li> |
| <p>In FreeMarker Classic, there were some utility classes |
| such as <code class="inline-code">freemarker.template.utility.Addition</code> |
| etcetera that existed as workarounds for the lack of numerical |
| operations in FreeMarker. Those have been removed and will |
| probably not be missed.</p> |
| </li> |
| |
| <li> |
| <p>In FreeMarker Classic, the <code class="inline-code">SimpleScalar</code> |
| object was mutable, it had a <code class="inline-code">setValue</code> method. |
| This was fairly obviously a design mistake. Any code that relied |
| on this must be refactored. Note that in this release, both |
| <code class="inline-code">SimpleScalar</code> and the newly introduced |
| <code class="inline-code">SimpleNumber</code> are both immutable and |
| final.</p> |
| </li> |
| </ul> |
| |
| |
| |
| |
| |
| <h2 class="content-header header-section2" id="autoid_240">Syntactical Miscellany</h2> |
| |
| |
| <ul> |
| <li> |
| <p>The if-elseif-else syntax was introduced. FreeMarker |
| classic only had if-else. This construct should probably (in the |
| opinion of the author of this document -- Revusky) be used in |
| preference to switch-case since the switch-case with |
| fall-through is a notoriously error-prone construct for most |
| mortal men.</p> |
| </li> |
| |
| <li> |
| <p>You can now do a multiple assignment in one |
| <assign...> directive. For example: <code class="inline-code"><assign x |
| = 1, y = price*items, message="foo"></code></p> |
| </li> |
| |
| <li> |
| <p>A scalar will no longer be interpreted as a one-item list |
| in a <list...> or <#foreach...> block. If you have |
| code that relied on this feature, there is an easy workaround, |
| since you can simply define a list literal with exactly one |
| item.</p> |
| |
| |
| |
| <div class="code-wrapper"><pre class="code-block code-template"> <assign y=[x]> |
| <strong>and then...</strong> |
| <list y as item>...</list> </pre></div> |
| </li> |
| </ul> |
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