The ActionScript code generation target

Note: The ActionScript target was last synced with the 3.2 version of ANTLR, and is no longer being actively maintained.

The ActionScript target closely follows the Java target. The API and runtime behavior are consistent to the extent possible.

Please send bug reports, feedback, patches to me or the to the antlr-interest mailing list.

Requirements

The runtime generates ActionScript 3 code designed to work with Flex version 2 or higher from Adobe. The runtime binary libraries are all compiled with the latest Flex 3.2 SDK.

To use generated code, you'll need to include ActionScript runtime package antlr3.swc in your library path. There are no other dependencies beyond the standard Flex libraries. Note, that the library contains some Adobe AIR class references, to use the library in a pure Flex project use the -library-path compiler option rather than the -include-library option when compiling from the command line.

Usage

Selecting ActionScript output

...

For a grammar T.g ANTLR3 will then create the files TLexer.as and TParser.as which contain the classes TLexer and TParser (or just one of those, if you have a pure lexer/parser). For tree parsers, ANTLR3 creates T.as containing the class T.

Specifying an ActionScript package for your recognizer

You can specify that your generated recognizer should be declared within a specific package as shown below. By default all recognizers are generated as top-level types with no enclosing package.

grammar MyGrammar;

options
{
    language=ActionScript;
}

@parser::package { My.Custom.NameSpace.For.Parser.In.Combined.Grammar } // Or just @package { ... }

@lexer::package { My.Custom.NameSpace.For.Lexer.In.Combined.Grammar }

// rest of grammar follows
....

lexer grammar MyGrammar;

options
{
    language=ActionScript;
}

@package { My.Custom.NameSpace.For.Lexer }

// rest of grammar follows
....

parser grammar MyGrammar;

options
{
    language=ActionScript;
}

@package { My.Custom.NameSpace.For.Parser }

// rest of grammar follows
....

tree grammar MyGrammar;

options
{
    language=ActionScript;
}

@package { My.Custom.NameSpace.For.TreeParser }

// rest of grammar follows
....

Using the generated classes

...

package {

	import org.antlr.runtime.*;

	public class AntlrActionScriptTest {
		public function AntlrActionScriptTest (input:String):void {
			var lexer:TLexer = new TLexer(new ANTLRStringStream(input));
			var tokens:CommonTokenStream = new CommonTokenStream(lexer);

			var parser:TParser = new TParser(tokens);
			parser.entry_rule();
 		}
	}
}

For complex parsers, you may want to avoid creating the lexers and parsers each time you want to parse input. In this case you can do the following, which will reset the lexer and parser by setting the charStream or tokenStream property (as appropriate):

package {

	import org.antlr.runtime.*;

	public class AntlrActionScriptTest {

		private static var lexer:TLexer = new TLexer(null);
		private static var parser:TParser = new TParser(null);

		public function parseInput(input:String):void {
			lexer.charStream = new ANTLRStringStream(input);
			parser.tokenStream = new CommonTokenStream(lexer);
			parser.entry_rule();
 		}
	}
}

If you want to access the tokens types in your code, you'll have to import and access them from the lexer or parser module (e.g. TLexer.EOF, TLexer.IDENTIFIER):

...

For grammars T.g (parser and lexer) and TWalker.g (the tree parser):

package {

	import org.antlr.runtime.*;
	import org.antlr.runtime.tree.*;

	public class AntlrActionScriptTreeWalkerTest {
		public function AntlrActionScriptTest (input:String):void {
			var lexer:TLexer = new TLexer (new ANTLRStringStream(input));
			var tokens:CommonTokenStream = new CommonTokenStream(lexer);

			var parser:TParser = new TParser(tokens);
			var r:ParserRuleReturnScope = parser.entry_rule();

			// This is the root of the AST.
			var root:Tree = r.tree;

			var nodes:CommonTreeNodeStream = new CommonTreeNodeStream(root);
			nodes.tokenStream = tokens;
			var walker:TWalker = new TWalker(nodes);
			walker.entry_rule();

 		}
	}
}

...

• -debug option: mostly useful for integration into ANTLRWorks.
• output=template: StringTemplate has not been ported to ActionScript, so template-based recognizers are not supported.