2014-08-24

antlr4快速开始（一）

antlr是什么？

ANTLR (ANother Tool for Language Recognition) 是一个强大的解析生成器，它可以读，处理，执行或者转换格式化的文本或者二进制文件。它被广泛的用于构建语言，工具，和框架。从语法上来说，antlr生成了一个能够构建和遍历解析树的解析器。

快速开始

Windows
Download http://antlr.org/download/antlr-4.4-complete.jar.
Add antlr4-complete.jar to CLASSPATH, either:
Permanently: Using System Properties dialog > Environment variables > Create or append to CLASSPATH variable
Temporarily, at command line:
SET CLASSPATH=.;C:\Javalib\antlr4-complete.jar;%CLASSPATH%
Create batch commands for ANTLR Tool, TestRig in dir in PATH
 antlr4.bat: java org.antlr.v4.Tool %*
 grun.bat:   java org.antlr.v4.runtime.misc.TestRig %*

例子

grammar Expr;        
prog:    (expr NEWLINE)* ;
expr:    expr ('*'|'/') expr
    |    expr ('+'|'-') expr
    |    INT
    |    '(' expr ')'
    ;
NEWLINE : [\r\n]+ ;
INT     : [0-9]+ ;


$ antlr4 Expr.g4
$ javac Expr*.java
$ grun Expr prog -gui
100+2*34
^D

注意：(That ^D means EOF on unix; it’s ^Z in Windows.) The -tree option prints the parse tree in LISP notation.