Announcing CLI11 Version 1.0

CLI11, a powerful library for writing command line interfaces in C++11, has just been released. There are no requirements beyond C++11 support (and even <regex> support not required). It works on Mac, Linux, and Windows, and has 100% test coverage on all three systems. You can simply drop in a single header file (CLI11.hpp available in releases) to use CLI11 in your own application. Other ways to integrate it into a build system are listed in the README.

The library was inspired the Python libraries Plumbum and Click, and incorporates many of their user friendly features. The library is extensively documented, with a friendly introduction, a tutorial filled (in progress) GitBook, and more technical API docs.

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Perfect forwarding for methods

I often see perfect forwarding listed for constructor arguments, but not usually for functions with a return or methods. Here is my solution for an method method of class Cls:

template<typename ...Args>
static auto method(Cls* cls, Args &&  ...args)
  -> typename std::result_of<decltype(&Cls::method)(Cls, Args...)>::type {
    return cls->method(std::forward<Args>(args)...);

This is useful if you want to call protected classes from a “helper” friend class, for example, to expose them to tests without having to require GoogleTest/GoogleMock to be available for regular users.

Lua Environment Modules

This is a guide to setting up Lmod (lua environment modules) on a CentOS system. I’ve used a similar procedure to set them up on a Mac, as well, so this is still a useful guide to the workings of Lmod if you use a different system; mostly paths will change. On a Mac, you’ll want to install Lmod from the science tap in brew. There are several good pages covering environment modules (TCL version), but not many that use the newer Lua syntax. This document aims to fill that roll.

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GoogleTest and CMake

This is a quick recipe for setting up CMake to use googletest in your projects. First, make a tests folder in the root of your project. Then, add add_subdirectory(tests) to your CMakeLists.txt, after you’ve finished adding the libraries in your project. Note that the way I’ve written this probably requires CMake 3.4+.

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A simple introduction to asyncio

This is a simple explanation of the asyncio module and new supporting language features in Python 3.5. Even though the new keywords async and await are new language constructs, they are mostly1 useless without an event loop, and that is supplied in the standard library as asyncio. Also, you need awaitable functions, which are only supplied by asyncio (or in the growing set of async libraries, like asyncssh, quamash etc.).

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A little example of how asyncio works

This is a simple example to show how Asyncio works without using Asyncio itself, instead using a basic and poorly written event loop. This is only meant to give a flavor of what Asyncio does behind the curtains. I’m avoiding most details of the library design, like callbacks, just to keep this simple. Since this is written as an illustration, rather than real code, I’m going to dispense with trying to keep it 2.7 compatible.

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