Create a fully functioning command line interface with 1.5 lines of code | Hacker News Reader

Create a fully functioning command line interface with 1.5 lines of code

github.com

43 pointsvitaut20 comments

I can also write a fully functioning web application in 1 line of code if I exclude how big each dependency is.

If you can actually do that, it reflects positively on your dependency's ability to make simple cases short and easy. Many libraries and frameworks actually don't.

That's what this is about.

The example is clearly 9 lines long and included fire.hpp has 703 lines of source code excluding comments.

It also requires several megabytes of standard library, kernel, operating system and compiler, but the point is that you don't have to write them. That's why you use libraries.

If we're playing CLI golf why not use macros to make it even dryer?

    int fired_main(int x = fire::arg("-x"), int y = fire::arg("-y"))

could just be

    int fired_main(int fire_arg(x), int fire_arg(y))

with something like

    #define fire_arg(v) v = fire::arg("-"#v)

The C preprocessor is still the thing I miss most when working in any other language.

It's unfortunate you can't just write something like:

    FIRE(args) {
        // ...
    }

without the explicit registration step. Unfortunately in this case the macro FIRE should first declare the fired function, then main, then defined the fired function, and this would be problematic because the definition can't have the default values for arguments again. I can't see a way around that.

Funny, jut a couple days ago I started using dotnet's System.CommandLine.DragonFruit which is similar in design philosophy to this - a main function with typed parameters and extra annotations. I would have never thought about this type of approach, or if I did I likely would have rejected it outright in favor of more typical classes / functions to do it, but I admit it's convenient for a quick tool.

This reminds me of Click for Python in that the CLI is built based on the functions that describe the commands and arguments.

Click uses decorators though. I don’t know what the C++ equivalent could be.

I'd love a good library to handle an interactive prompt and state machine. You know press 1/2/3 for x/y/z etc. Java especially

Somebody should explain that std::endl instead of '\n' is pointless, verbose, and also slow.

Nice. boost::program_options needs a rethink for modern c++

What does 1.5 lines of code mean?

'Give me your attention'.

I was wondering the same thing. Perhaps he means all the extra "fire::" annotations one needs to put in place in function parameter lists as well as the ultimate dispatcher instatiating cpp macro? Really there is always at least 2.5 with the #include <fire.h>, later macro and annotations.

https://github.com/c-blake/cligen achieves the actual 1-line of code dream without extra annotations and even leveraging existing API documentation and even colorizing said rST docs in terminal generated help output. { Of course, that one line might be an "import cligen; dispatch(foo)" which is arguably denser than most people would format it. } One usually wants to add some per-parameter help, though, unless your parameter names are always much more descriptive than "x" and "y".

I think 1 line to modify the function sig, and .5 to call the library

Its purely marketing math, I think.

I think it’s the opposite

Neither alternative makes sense, so you are both correct.

>Note that parsing and conversion takes up just 0.5 lines of fired_main().

The last line calls fired_main and is the full line.

The definition of the function fired_main is similar to the definition of the function main, so it is not an extra line that is needed. But about half of the line deal with describing the command line arguments.

Anything for C#?

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