ANTLR3 C sample

build.sh

#!/bin/sh
antlr3 test.g
g++ *.cc *.c -o t -lantlr3c

test

a = 1 + 2 * 3;
b = (1 + 2) * 3;
a * b;

test.cc

#include <map>
#include <string>

#include "testLexer.h"
#include "testParser.h"

std::map<std::string,int> table;

int eval(pANTLR3_BASE_TREE expr) {
    int type = expr->getType(expr);
    if (type == PLUS) {
        pANTLR3_BASE_TREE left = (pANTLR3_BASE_TREE)expr->getChild(expr, 0);
        pANTLR3_BASE_TREE right = (pANTLR3_BASE_TREE)expr->getChild(expr, 1);
        return eval(left) + eval(right);
    } else if (type == MUL) {
        pANTLR3_BASE_TREE left = (pANTLR3_BASE_TREE)expr->getChild(expr, 0);
        pANTLR3_BASE_TREE right = (pANTLR3_BASE_TREE)expr->getChild(expr, 1);
        return eval(left) * eval(right);
    } else if (type == ID) {
        std::string name((const char *)expr->getText(expr)->chars);
        return table[name];
    } else if (type == DIGIT) {
        pANTLR3_UINT8 value = expr->getText(expr)->chars;
        return atoi((const char *)value);
    }
}

int main() {
    pANTLR3_UINT8 filename = (pANTLR3_UINT8)"test";
    pANTLR3_INPUT_STREAM input = antlr3AsciiFileStreamNew(filename);
    ptestLexer lexer = testLexerNew(input);
    pANTLR3_COMMON_TOKEN_STREAM stream = antlr3CommonTokenStreamSourceNew(ANTLR3_SIZE_HINT, TOKENSOURCE(lexer));
    ptestParser parser = testParserNew(stream);
    testParser_translation_unit_return unit = parser->translation_unit(parser);
    pANTLR3_BASE_TREE tree = unit.tree;

    for (int i = 0; i < tree->getChildCount(tree); i++) {
        pANTLR3_BASE_TREE stat = (pANTLR3_BASE_TREE)tree->getChild(tree, i);
        if (stat->getType(stat) == ASSIGN) {
            pANTLR3_BASE_TREE id = (pANTLR3_BASE_TREE)stat->getChild(stat, 0);
            pANTLR3_BASE_TREE expr = (pANTLR3_BASE_TREE)stat->getChild(stat, 1);
            std::string name((const char *)id->getText(id)->chars);
            int value = eval(expr);
            table[name] = value;
        } else {
            int value = eval(stat);
            printf("%d\n", value);
        }
    }

    return 0;
}

test.g

grammar test;

options {
    language = C;
    k = 2;
    output = AST;
}

translation_unit:
    statement+ EOF -> statement+;

statement:
    stat_assign NL -> stat_assign |
    expression NL -> expression;

expression:
    expr_add;

stat_assign:
    identifier ASSIGN expression -> ^(ASSIGN identifier expression);

expr_add:
    expr_mul (PLUS expr_add)? -> ^(PLUS expr_mul expr_add);

expr_mul:
    expr_primary (MUL expr_mul)? -> ^(MUL expr_primary expr_mul);

expr_primary:
    constant |
    identifier |
    '(' expression ')' -> expression;

constant: DIGIT;

identifier: ID;

DIGIT: (('1'..'9') ('0'..'9')*) | '0';
ID: ('a'..'z') ('a'..'z' | '0'..'9')*;
WS: (' ' | '\n')+ {$channel = HIDDEN;};
NL: ';';
ASSIGN: '=';
PLUS: '+';
MUL: '*';