用ANTLR3实现规则解析----1-安装

1、安装antlr3.4 运行环境

  首先从antlr官网下载处，获取了libantlr3c-3.4.tar.gz下载包

 按照install文件的说明的安装步骤执行安装

  #1 ./configure

  #2 make;  这一步报错

/usr/include/gnu/stubs.h:7:27: error: gnu/stubs-32.h: No such file or directory

     /usr/lib/gcc/x86_64-redhat-linux/4.1.2/include/stddef.h:214: error: duplicate 'unsigned'/usr/lib/gcc/x86_64-redhat-linux/4.1.2/include/stddef.h:214: error: two or more data types in declaration specifiers

      原因：我的系统是64位的，所以第一步应该为 ./configure  --enable-64bit

  #3 make install

2、安装antlr tool

    #1、先安装java

    #2、cd  /usr/local/lib

         wget   antlr-3.5-complete.jar

        export CLASSPATH=/usr/local/lib/antlr-3.5-complete.jar:$CLASSPATH

    #3、运行：java org.antlr.Tool

2、antlr上手--hello world

   http://www.antlr.org/wiki/display/ANTLR3/Five+minute+introduction+to+ANTLR+3

  上有antlr3的例子，这里我们用c++例子，这是一个简单的 计算器，支持 + - * /

   #1、grammar文件 保存为

 ExprCppTree,g 文件

grammar ExprCppTree;

options {
    language = C;
    output = AST;
    ASTLabelType=pANTLR3_BASE_TREE;
}

@header {
    #include <assert.h>
}

// The suffix '^' means make it a root.
// The suffix '!' means ignore it.

expr: multExpr ((PLUS^ | MINUS^) multExpr)*
    ;

PLUS: '+';
MINUS: '-';

multExpr
    : atom (TIMES^ atom)*
    ;

TIMES: '*';

atom: INT
    | ID
    | '('! expr ')'!
    ;

stmt: expr NEWLINE -> expr  // tree rewrite syntax
    | ID ASSIGN expr NEWLINE -> ^(ASSIGN ID expr) // tree notation
    | NEWLINE ->   // ignore
    ;

ASSIGN: '=';

prog
    : (stmt {pANTLR3_STRING s = $stmt.tree->toStringTree($stmt.tree);
             assert(s->chars);
             printf(" tree \%s\n", s->chars);
            }
        )+
    ;

ID: ('a'..'z'|'A'..'Z')+ ;
INT: '~'? '0'..'9'+ ;
NEWLINE: '\r'? '\n' ;
WS : (' '|'\t')+ {$channel = HIDDEN;};

  #2、运行：java org.antlr.Tool  ExprCppTree,g 

 #3、加入main.c

#include "ExprCppTreeLexer.h"
#include "ExprCppTreeParser.h"
#include <cassert>
#include <map>
#include <string>
#include <iostream>

using std::map;
using std::string;
using std::cout;

class ExprTreeEvaluator {
    map<string,int> memory;
public:
    int run(pANTLR3_BASE_TREE);
};

pANTLR3_BASE_TREE getChild(pANTLR3_BASE_TREE, unsigned);
const char* getText(pANTLR3_BASE_TREE tree);

int main(int argc, char* argv[])
{
  pANTLR3_INPUT_STREAM input;
  pExprCppTreeLexer lex;
  pANTLR3_COMMON_TOKEN_STREAM tokens;
  pExprCppTreeParser parser;

  assert(argc > 1);
  input = antlr3FileStreamNew((pANTLR3_UINT8)argv[1],ANTLR3_ENC_8BIT);
  lex = ExprCppTreeLexerNew(input);
  tokens = antlr3CommonTokenStreamSourceNew(ANTLR3_SIZE_HINT,
                                            TOKENSOURCE(lex));
  parser = ExprCppTreeParserNew(tokens);

  ExprCppTreeParser_prog_return r = parser->prog(parser);

  pANTLR3_BASE_TREE tree = r.tree;

  ExprTreeEvaluator eval;
  int rr = eval.run(tree);
  cout << "Evaluator result: " << rr << '\n';

  parser->free(parser);
  tokens->free(tokens);
  lex->free(lex);
  input->close(input);

  return 0;
}

int ExprTreeEvaluator::run(pANTLR3_BASE_TREE tree)
{
    pANTLR3_COMMON_TOKEN tok = tree->getToken(tree);
    if(tok) {
        switch(tok->type) {
        case INT: {
            const char* s = getText(tree);
            if(s[0] == '~') {
                return -atoi(s+1);
            }
            else {
                return atoi(s);
            }
        }
        case ID: {
            string var(getText(tree));
            return memory[var];
        }
        case PLUS:
            return run(getChild(tree,0)) + run(getChild(tree,1));
        case MINUS:
            return run(getChild(tree,0)) - run(getChild(tree,1));
        case TIMES:
            return run(getChild(tree,0)) * run(getChild(tree,1));
        case ASSIGN: {
            string var(getText(getChild(tree,0)));
            int val = run(getChild(tree,1));
            memory[var] = val;
            return val;
        }
        default:
            cout << "Unhandled token: #" << tok->type << '\n';
            return -1;
        }
    }
    else {
        int k = tree->getChildCount(tree);
        int r = 0;
        for(int i = 0; i < k; i++) {
            r = run(getChild(tree, i));
        }
        return r;
    }
}

pANTLR3_BASE_TREE getChild(pANTLR3_BASE_TREE tree, unsigned i)
{
    assert(i < tree->getChildCount(tree));
    return (pANTLR3_BASE_TREE) tree->getChild(tree, i);
}

const char* getText(pANTLR3_BASE_TREE tree)
{
    return (const char*) tree->getText(tree)->chars;
}

 #4、编译：g++ -g -Wall *.c -o test -I. -L /usr/local/lib  -lantlr3c

#5、运行

        ./test a（a为文件，可简单写入 1+1)

         tree (+ 1 1)
        Evaluator result: 2