xcpp

xcpp is convention over configuration for C++. It is a tool that lets you write, run, watch and build C++ code quickly and simply. xcpp stands for execute C++. It compiles and runs your code in a pre-configured environment: you just write C++. The xcpp environment preincludes all C++ Standard Library headers and it is "using namespace std;" all of it for you. In addition to having all the std namespace ready to use, xcpp provides extra basic functions and types to simplify your C++ development, like simplified handling of i/o streams errors (print and read functions), string manipulations (trim, rtrim, ltrim, concat, concat_range) and new algorithms like purge and purge_if algorithms (purge is erase–remove, a well-known C++ idiom).

xcpp can compile with g++ (or gcc) and clang. If your code is processing a lot of data, you will benefit from using xcpp because you will be running directly on the CPU in binary operations instead of being interpreted.

Install

xcpp is a self-contained bash script: just download the "xcpp" file and copy it where it can be run, like /usr/local/bin or somewhere else that is in your $PATH.

How does it work?

First, you create a text file (.xcpp extension recommended). The first 7 lines of that file must be:

#if !defined(__XCPP__)
#define __XCPP__ 0
#elif defined(__XCPP__)
#pragma once
#else
. xcpp run "$0" "$@"
#endif

With comments:

#if !defined(__XCPP__)  // This is the main xcpp file if __XCPP__ is not defined:
#define __XCPP__ 0        // We're in the main program file, define the xcpp version (0: in development).
#elif defined(__XCPP__) // Else if __XCPP__ is already defined, we're in header mode:
#pragma once              // Prevent multi inclusion.
#else                   // Else: this case is never true so it never reaches the C++ compiler.
. xcpp run "$0" "$@"     // All the previous lines are bash comments, now call the xcpp launcher.
#endif

After these 7 lines, you are free to write xcpp C++ code and the xcpp tool will be able to run, watch, build and test that code.

If you run a file named "filename.xcpp", the launcher compiles your source code and runs the function "filename". Command arguments are forwarded to your C++ code as strings to this function.

Here's the xcpp hello world example:

#if !defined(__XCPP__)
#define __XCPP__ 0
#elif defined(__XCPP__)
#pragma once
#else
. xcpp run "$0" "$@"
#endif

int hello_world( strings args )
{
	println( "Hello, world!" );
	return 0;
}

To run, simply:

xcpp run hello_world.xcpp

Another option: make it executable and then run it, just like a script.

chmod +x hello_world.xcpp
./hello_world.xcpp

The launcher will call the "hello_world" function, because the file is named hello.xcpp -- the extension doesn't matter.

Example 2: hello_you.xcpp

#if !defined(__XCPP__)
#define __XCPP__ 0
#elif defined(__XCPP__)
#pragma once
#else
. xcpp run "$0" "$@"
#endif

int hello_you( strings args )
{
	string name;
	print( "What is you name? " );
	if( readln( name ) )
	{
		println( "Hello, " + name + "!" );
	}
	else
	{
		println( "I'm sorry, I didn't hear ya." );
	}
	return 0;
}

Reserved keywords and identifiers

The xcpp keywords and reserved identifiers are:

• Of course, all the C++ keywords: https://en.cppreference.com/w/cpp/keyword

• Because xcpp preincludes all the C++ standard library, all the std symbols: https://en.cppreference.com/w/cpp/symbol_index

• xcpp adds some of its own identifiers and reserved keywords:

  • concat
  • print
  • println
  • fprint
  • fprintln
  • newline
  • read
  • readln
  • for_i
  • str
  • strings
  • sz
  • ssz
  • i8
  • i16
  • i32
  • i64
  • u8
  • u16
  • u32
  • u64
  • f32
  • f64
  • f128
  • seed_rand
  • purge
  • purge_if
  • within
  • trim
  • rtrim
  • ltrim
  • sleep_ms
  • press_enter
  • main
  • __XCPP_VERSION__
  • __XCPP__
  • __XCPP_RESERVED_HEADER_H__

  Scratch pad

  • Generate xhpp from make_xhpp.sh et un dossier ./src contenant le source de la lib en C++

  Example of package structure:

  • stb_perlin ** 0.2 *** make_xhpp.sh *** src/ ** 0.4 *** make_xhpp.sh *** src/