Simple Templated Recursive Logging Helper

logger.h

/*===============================================

Logging Helper

Author: Nicholas McDonald

Features:
- Templated Recursive Value Outputs
- Simplified Log File Writing
- Arbitrary Pre-Message Blurbs
- Elegant One-Line Failures / Errors

If a file is opened, all output is directed to the file.

===============================================*/

#include <cstdarg>
#include <string>
#include <iostream>

namespace logg{
using namespace std;

bool debug = true;
function<string()> blurb = [](){ return ""; };
ostream* target = &cout;
ofstream* file = NULL;

/*=============================
        Raw Recursion
=============================*/

void raw(){
  if(file == NULL) *target<<endl;
  else *file<<endl;
}

template <typename T>
void raw(T m){
  if(file == NULL) *target<<m<<endl;
  else *file<<m<<endl;
}

template <typename T, typename... Types>
void raw(T m, Types... r){
  if(file == NULL){ *target<<m; raw( r... ); }
  else { *file<<m; raw( r... ); }
}

/*=============================
        Regular Output
=============================*/

template <typename... Types>
void out(Types... r){ raw( blurb(), r... ); }

/*=============================
      Debugging Messages
=============================*/

template <typename... Types>
void dbg(Types... r){ if(debug) raw( r... ); }

template <typename... Types>
void dbg(bool f, Types... r){ if(f) raw( r... ); }

/*=============================
      Errors and Failures
=============================*/

template <typename... Types>
void err(Types... r){ raw( "[Error] ", r... ); }

template <typename... Types>
void fatal(Types... r){ raw( "[Fatal] ", r... ); exit(0); }

/*=============================
        Write to File
=============================*/

void close(){
  if(file != NULL)
    file->close();
  file = NULL;
}

void open(string name){
  close();
  file->open(name, ios::app);
  if(!file->is_open())
    fatal("Failed to open file ", name);
}

/*=============================
      Special Displays
=============================*/

template <typename T>
void progress(T d, T D){
  if(d != 0) cout<<"\r";
  cout<<"["<<d<<"/"<<D<<"]";

  for(int i = 0; i < 25; i++){
    if(i < 25*((float)d/(float)D)) cout<<"#";
    else cout<<"-";
  }
  cout<<"]";
  if(d == D-1) printf("\n");
}

};