program.cs

antlr小例子 。

using System;
using Antlr.Runtime;
using Antlr.Runtime.Tree;

namespace ANTLRTutorial
{
	class Program
	{
		static void Main(string[] args)
		{
			// sets the input string
			ANTLRStringStream strStream = new ANTLRStringStream(
				@"	a=3
					a+5
				");

			// creates the lexer
			ExprLexer lexer = new ExprLexer(strStream);

			// creates the parser with a stream of tokens that will be extracted from the lexer to it
			CommonTokenStream tokStream = new CommonTokenStream(lexer);
			ExprParser parser = new ExprParser(tokStream);

			// parse the input string and get the results
			ExprParser.prog_return returnValue = parser.prog();

			// creates the tree parser with a stream of tokens that will be extracted from the AST
			CommonTreeNodeStream treeNodeStream = new CommonTreeNodeStream((CommonTree)returnValue.Tree);
			EvalTreeParser treeWalker = new EvalTreeParser(treeNodeStream);

			// walk the AST executing any associated code
			treeWalker.prog();

			// get the AST and wrap it in our tree node class in order to visualize it with StructsViz when debugging
			// you can download an evaluation version of StructsViz here: http://www.manuelabadia.com/products
			//AntlrDebugCommonTree AST = new AntlrDebugCommonTree((CommonTree)returnValue.Tree);

			// to see the parse tree the parser has to be created with the -debug option, and call the parser
			// constructor with a second parameter. The value to pass to the second parameter should be an instance
			// of the ParseTreeBuilder class. The parse tree can be visualized in StructsViz using its related wrapper:
			// AntlrDebugParseTree parseTree = new AntlrDebugParseTree(parseTreeBuilder.GetTree());
			// beware that ANTLR 3.0b5 does not generate 100% working code when the using -debug. You need to change
			// a few things. This should be hopefully fixed in the next version.
		}
	}
}