compiler/src/main/java/org/apache/royale/compiler/tree/package.html - royale-compiler - Git at Google

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 <html>
 <body>

 This package and its subpackages contain classes and interfaces related
 to <i>abstract syntax trees</i>.

 <p>
 An <i>abstract syntax tree</i> or AST represents almost every detail of
 a source file in a hierarchical structure that reflects the logical
 structure of the source language.
 Each <i>node</i> in an AST is a type of <code>IASNode</code>.
 </p>

 <p>
 The information stored in each node is minimal and unimportant, such as
 the name of an identifier or keyword, or the text of a string literal.
 It is the many different node types, and the many ways that the nodes
 can be arranged -- in other words, the <i>tree shape</i> -- that
 contain the semantics of the AST.
 </p>

 <p>
 Each AST node stores location information about what source file it was in
 and the offsets where it starts and ends, which is useful for IDEs.
 For command-line error reporting, and for the code generation of debug
 opcodes, nodes also store line and column information. Deriving line
 and column from starting offset is too slow for code generation.
 </p>

 <p>
 In order to allow an IDE to efficiently search an AST for the node
 containing a particular offset, the nodes of an AST must obey the following
 rules regarding location information:
 <ul>
 <li>Sibling nodes must not overlap and must be in offset order.</li>
 <li>The start/end of a parent node must contain all its child nodes.</li>
 </ul>
 </p>

 <p>
 The immediate contents of this package is <code>ASTNodeID</code>,
 an enum containing a <i>node ID</i> for every kind of AST node.
 The node ID is used to identify nodes in the <code>.jbg</code> files
 that create the code generator's BURM (Bottom-Up Rewrite Machine).
 </p>

 <p>
 See the <code>org.apache.royale.compiler.tree.as</code>
 and <code>org.apache.royale.compiler.tree.mxml</code> subpackages
 for more information about AS and MXML trees.
 </p>

 </body>
 </html>
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	this work for additional information regarding copyright ownership.
	The ASF licenses this file to You under the Apache License, Version 2.0
	(the "License"); you may not use this file except in compliance with
	the License. You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

	Unless required by applicable law or agreed to in writing, software
	distributed under the License is distributed on an "AS IS" BASIS,
	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	See the License for the specific language governing permissions and
	limitations under the License.

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	<html>
	<body>

	This package and its subpackages contain classes and interfaces related
	to <i>abstract syntax trees</i>.

	<p>
	An <i>abstract syntax tree</i> or AST represents almost every detail of
	a source file in a hierarchical structure that reflects the logical
	structure of the source language.
	Each <i>node</i> in an AST is a type of <code>IASNode</code>.
	</p>

	<p>
	The information stored in each node is minimal and unimportant, such as
	the name of an identifier or keyword, or the text of a string literal.
	It is the many different node types, and the many ways that the nodes
	can be arranged -- in other words, the <i>tree shape</i> -- that
	contain the semantics of the AST.
	</p>

	<p>
	Each AST node stores location information about what source file it was in
	and the offsets where it starts and ends, which is useful for IDEs.
	For command-line error reporting, and for the code generation of debug
	opcodes, nodes also store line and column information. Deriving line
	and column from starting offset is too slow for code generation.
	</p>

	<p>
	In order to allow an IDE to efficiently search an AST for the node
	containing a particular offset, the nodes of an AST must obey the following
	rules regarding location information:
	<ul>
	<li>Sibling nodes must not overlap and must be in offset order.</li>
	<li>The start/end of a parent node must contain all its child nodes.</li>
	</ul>
	</p>

	<p>
	The immediate contents of this package is <code>ASTNodeID</code>,
	an enum containing a <i>node ID</i> for every kind of AST node.
	The node ID is used to identify nodes in the <code>.jbg</code> files
	that create the code generator's BURM (Bottom-Up Rewrite Machine).
	</p>

	<p>
	See the <code>org.apache.royale.compiler.tree.as</code>
	and <code>org.apache.royale.compiler.tree.mxml</code> subpackages
	for more information about AS and MXML trees.
	</p>

	</body>
	</html>