Question

I think I have a cyclic dependency issue and have no idea how to solve it….
To be as short as possible:
I am coding something like a html parser.
I have a main.cpp file and two header files Parser.h and Form.h.
These header files hold the whole definitions… (I’m too lazy to make the corresponding .cpp files…

Form.h looks like this:

//... standard includes like iostream....

#ifndef Form_h_included
#define Form_h_included

#include "Parser.h"
class Form {
public:
    void parse (stringstream& ss) {

        // FIXME: the following like throws compilation error: 'Parser' : is not a class or namespace name
        properties = Parser::parseTagAttributes(ss);

        string tag = Parser::getNextTag(ss);
        while (tag != "/form") {
            continue;
        }
        ss.ignore(); // >
    }
// ....
};
#endif

and Parser.h looks like this:

// STL includes
#ifndef Parser_h_included
#define Parser_h_included

#include "Form.h"

using namespace std;

class Parser {
public:
    void setHTML(string html) {
         ss << html;
    }
    vector<Form> parse() {
        vector<Form> forms;

        string tag = Parser::getNextTag(this->ss);
        while(tag != "") {
            while (tag != "form") {
                tag = Parser::getNextTag(this->ss);
            }
            Form f(this->ss);
            forms.push_back(f);
        }
    }
// ...
};
#endif

Don’t know if it is important, but I’m doing the build in MS Visual Studio Ultimate 2010
and it throws me
‘Parser’ : is not a class or namespace name

How to solve this problem?
Thank you!

Answer 1

What you probably want to do here is leave the method declaration in the header like so

class Form {
public:
    void parse (stringstream& ss);
// ....
};

And define the method in a source file (i.e. a Form.cpp file) like so

#include "Form.h"
#include "Parser.h"

void parse (stringstream& ss) {

    properties = Parser::parseTagAttributes(ss);

    string tag = Parser::getNextTag(ss);
    while (tag != "/form") {
        continue;
    }
    ss.ignore(); // >
}

That should resolve the cyclic dependency issue you’re seeing…