RegExp-example.cpp

BUGS! Reads a regular expression std::string and stores it in a preprocessed format. BUGS! Calling exp() later does not work!

Based on POSIX regex functions <regex.h>, see man regex.

Examples: RegExp-example.cpp

/*
 
    Copyright 2001 - 2017  Markus Peura, Finnish Meteorological Institute (First.Last@fmi.fi)
 
 
    This file is part of Rack for C++.
 
    Rack is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    any later version.
 
    Rack is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Lesser Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with Rack.  If not, see <http://www.gnu.org/licenses/>.
 
 */
 
/*
 
  REQUIRE: drain/{RegExp,Sprinter,Type}.cpp
 
 */
#include <iostream>
#include <stdexcept>
#include "drain/RegExp.h"
 
 
using namespace std;
using namespace drain;
 
int main(int argc, char **argv){
 
    if (argc==1){
        cout << "Usage: " << argv[0] << "<regexp> # Reports if ok as regexp\n";
        cout << "Usage: " << argv[0] << "<regexp> <string> # Reports if matches\n";
        cout << "Usage: " << argv[0] << "<regexp> <string> <replace> # Reports if matches\n";
        // cerr << "Example:\n  " << argv[0] << " '^.*(\\\\{[a-s]+\\\\}).*$'  'Testing {foo} content...'  '...and {test} as well'\n";
        cerr << "Example:\n  ";
        cerr << argv[0] << " '.*(data|dataset)([0-9]+)/(data|quality)([0-9]+)/?$' /dataset1/data4/quality2 \n";
        cerr << argv[0] << " '([[:alpha:]]{1,3})-([[:digit:]]{1,3})$' TAV-378 \n";
        cerr << argv[0] << " '^[ ]*(([-+]?[0-9]*)(\\.[0-9]+)?)([eE][-+]?[0-9]+)?[ ]*$' -123.456e+789 1357 hello  \n";
        // ^[ ]*[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?[^0-9]*$
        return 0;
    }
 
    REG_EXTENDED;
 
    RegExp numberCheck("[[:digit:]]"); //  numberCheck("([0-9])");
    RegExp alphaCheck("[[:alpha:]]"); //  alphaCheck("[a-zA-Z]");
    RegExp nonAlphaCheck("[^[:alnum:]]"); //
 
    RegExp userExp;
    try {
        userExp.setExpression(argv[1]);
    }
    catch (const exception &e) {
        std::cerr << e.what() << endl;
        std::cerr << "Syntax error in RegExp:" << argv[1] << std::endl;
        return 1;
    }
 
    if (argc == 2){
        std::cout << "RegExp OK, '" << userExp << "'\n"; // requires TypeName<RegExp>
        return 0;
    }
 
    std::string s(argv[2]);
    std::string result;
 
 
    if (numberCheck.test(s)){
        std::cout << "- contains digits\n";
        numberCheck.replace(s, "*", result);
        std::cout << "  --> replace digits:\n\t" << result << '\n';
    }
 
    if (alphaCheck.test(s))
        std::cout << "- contains alphabets\n";
 
    if (nonAlphaCheck.test(s))
        std::cout << "- contains non-alphanumeric chars\n";
 
    std::cout << "Testing string '" << s << "' with RegExp='" << userExp << "'\n";
    if (userExp.execute(s) != REG_NOMATCH){
 
        std::cerr << "ACCEPTED\n";
        cerr << '\t' << 0 << " ==\t " << userExp.result[0] << '\n';
        for (std::size_t j = 1; j < userExp.result.size(); ++j) {
            cerr << '\t' << j << "  = \t'" << userExp.result[j] << "'\n";
        }
        std::cout << '\n';
 
        // Proceed to replace op, if argument issued.
        if (argc == 4){
            std::string rep(argv[3]);
            std::cout << "Replace with '" << rep << "':\n";
            userExp.replace(s, rep, result);
            std::cout << result << '\n';
            std::cout << '\n';
        }
 
    }
    else
        std::cerr << "REJECTED\n";
 
    std::cout << '\n';
 
 
 
    /* These are for valgrind checks only
     */
    numberCheck.setExpression("");
    numberCheck.setExpression("test");
 
    return 0;
}