Improvement suggestion to support OOP

[lafrank]

In an OOP environment the GlobalMatch callback functionality is very restrictive.

Would it be possible to implement a base callback class with a callback virtual function to later build upon this class, ?
I tried below but I have difficulties with syntax since I am not much experienced with c++.

Could ypu please help to fix below - or suggest something similar - and if works it might be a good candidate for an MR.

In regexp.h :

class GlobalMatchClass;

typedef void (*GlobalMatchClassCallback) (GlobalMatchClass::*matchcallback)(const char* match,  const unsigned int length,  const MatchState& ms);  

typedef class GlobalMatchClass
{
public:
  virtual void matchcallback(const char* match, const unsigned int length, const MatchState& ms);
} GlobalMatchClass;

In regexp.cpp:

unsigned int MatchState::GlobalMatchCM(const char* pattern, GlobalMatchClassCallback f)
{
  // Same as MatchState::GlobalMatch, probably invocation of f must be different
}

void GlobalMatchClass::matchcallback(const char* match, const unsigned int length, const MatchState& ms) {}

The code above is not correct, has either syntactical or semantical issues, I am not quite sure what is wrong.

Appreciate your help in advance.