Question

#include <stdio.h>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
#include <regex>

using namespace std;

class Parser {
protected:
    // regex: containers
    static const regex rxProc("procedure\s+([\w]+)\s*{");
}

I am getting an error for the "procedure\s+([\w]+)\s*{" part. Expected a type specifier. I must be doing something wrong?

Answer 1

Look at the other answers here to understand what are you actually asking the compiler. If you are trying to make a constant inside your class – I provide a solution here.

Using static members in C++ is fun, but only for POD (plain-old-data) members. For more complex members things get ugly. Even for char* this does not scale up. Using good old C #defines is sometimes a good idea – even in C++;

Something like this will fix your compilation problem. Play with the #if 0 to trigger your old code, and compile using g++ -std=gnu++0x -c test1.cpp

#include <stdio.h>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <algorithm>
#include <regex>

using namespace std;

#if 0
// my fix

// in your H file
class Parser {
protected:
    // regex: containers
    static const regex rxProc;
};    
// in your CPP file
const regex Parser::rxProc = regex("procedure\\s+([\\w]+)\\s*{");
#else

// your old code
class Parser {
protected:
    // regex: containers
    static const regex rxProc("procedure\\s+([\\w]+)\\s*{");
};
#endif

(not even getting into the issue of using regex to define a syntax tree… or parsing a Pascal file… which is just bad idea and will break oh, so, many times… just don’t)