ExtendedCPP

ExtendedCPP is a c++ parser using parser-toolkit. It allows to extend c++ language features by transpiling.

Motivation

Compared to newer languages c++ is sometimes behind in terms of feature sets. To no offense this is for good reason. Creating language features needs to be tested and planned carefully, ExtendedCPP let's you do this.

Why wouldn't you just extend clang since it also provides some experimental features (modules for instance)? Clang is a compiler while extended-cpp is a transpiler. extended-cpp only transforms code to standardized c++ code without the need to modify llvm/assembly. Besides that extended-cpp allows quick prototyping and is easy to use.

Introduction

ExtendedCPP is designed to allow modern features in c++ before it is actually part of the standard.

Feature List

Note that extended-cpp equips a fully powered c++ parser which can be used to parse c++ without any transpiling. It's using parser-toolkit as a backend for parsing and analyzing, this means syntax and grammar can also be applied to your custom language/syntax created with parser-toolkit to allow for example inline c++ blocks. (with or without extensions)

To get an overview of all features and their wip state, see the specification/ folder.

Feature namespacing

• base: Basic language features that are required to parse normal c++11.
• std: Stable additional features that are considered the standard of extended c++. It should be always safe to use all.
• extra: Stable additional features that don't fit the standard yet due to issues with other features for example.
• dev: In development features that are not considered stable / ready yet. Syntax changes might still happen here.

Feature versioning

All features expect the features in the base namespace are versioned. The version of the features MUST be always added to the feature list. When a feature moves one namespace up the version is reset to v1. Only major versions are tracked in the feature list. Only changes that might break existing usage.

Usage

// build_script.js
// -----------------

// Transpiling
// ---------------------
const ExtendedCpp = require('extended-cpp');

const cpp = new ExtendedCpp([
  // feature list
  ...ExtendedCpp.base.all,
  ExtendedCpp.std.modules.v1,
  ExtendedCpp.extra.tuples.v1,
  ...
]);

cpp.addSource('my_module_a.cpp');
cpp.addSource('my_module_b.cpp');
cpp.transpile('temp/');

// Compiling
// ------------------
cpp.compile();
// Note: compile() will use ${CXX} environment variable as a compiler