Crazy expressions parser

main.cpp

#include <iostream>
#include <string>
#include <vector>

class Token {
    typedef std::vector<std::string> TokenList;

    TokenList _tokens;
public:
    Token(std::string t) {
        t = std::string("Token[") + t + "]";
        _tokens.push_back(t);
    }

    Token(const TokenList &tl) : _tokens(tl) {
    }

    const TokenList& tokens() const { return _tokens; }
};

Token op(std::string operation, const Token &a) {
    std::vector<std::string> tokens;
    tokens.push_back(operation);
    tokens.insert(tokens.end(), a.tokens().begin(), a.tokens().end());
    return Token(tokens);
}

Token op(std::string operation, const Token &a, const Token &b) {
    std::vector<std::string> tokens;
    tokens.push_back(operation);
    tokens.insert(tokens.end(), a.tokens().begin(), a.tokens().end());
    tokens.insert(tokens.end(), b.tokens().begin(), b.tokens().end());
    return Token(tokens);
}

Token brackets(const Token &a) {
    std::vector<std::string> tokens;
//    tokens.push_back("BRACKET_OPEN");
    tokens.insert(tokens.end(), a.tokens().begin(), a.tokens().end());
//    tokens.push_back("BRACKET_CLOSE");
    return Token(tokens);
}

Token operator+(const Token &a, const Token &b) {
    return op("ADD", a, b);
}

Token operator*(const Token &a, const Token &b) {
    return op("MUL", a, b);
}

Token operator/(const Token &a, const Token &b) {
    return op("DIV", a, b);
}

Token operator-(const Token &a, const Token &b) {
    return op("SUB", a, b);
}

Token operator-(const Token &a) {
    return op("MINUS", a);
}

Token operator^(const Token &a, const Token &b) {
    return op("XOR", a, b);
}

Token operator|(const Token &a, const Token &b) {
    return op("BIT_OR", a, b);
}

Token operator&(const Token &a, const Token &b) {
    return op("BIT_AND", a, b);
}

Token operator&&(const Token &a, const Token &b) {
    return op("AND", a, b);
}

Token operator||(const Token &a, const Token &b) {
    return op("OR", a, b);
}

std::ostream& operator<<(std::ostream &out, Token &token) {
    const std::vector<std::string> &tl = token.tokens();
    for (size_t i = 0, length = tl.size(); i < length; ++i) {
        out << tl[i] << " ";
    }
    return out;
}

int main() {
    #include "expr"

    std::cout << val << std::endl;
}

parser.py

import subprocess
import re
import os
 
print "Input expression and we'll parse it!"
expr = raw_input('--> ')
 
tokens = re.findall("(\\w+)", expr)
expr2 = re.sub("(\\w+)", "t\\1", expr)
 
f = open("expr", "w")
content = ""
for i in set(tokens):
    content += 'Token t' + i + '("' + i + '");'
 
content += "Token val = (" + expr2 + ");"
f.write(content)
f.close()
 
proc = subprocess.Popen("g++ main.cpp -o prog", shell=True, stderr=subprocess.PIPE)
 
if proc.stderr.readline() == "":
    proc = subprocess.Popen("./prog", shell=True, stdout=subprocess.PIPE)
    ans = proc.stdout.readline()
    os.remove("prog")
    print ans
else:
    print "Error, check your expression"