std.getopt.problem.d

std.getopt.problem.d

#!/usr/bin/env rdmd

/*
  Author  : Ky-Anh Huynh
  License : MIT
  Purpose : A bug in std.getopt
  Date    : 2018 07 29
  Description:

$ dmd --version
DMD64 D Compiler v2.081.1-dirty
Copyright (C) 1999-2018 by The D Language Foundation, All Rights Reserved written by Walter Bright

$ rdmd tests.d  -l -long --long --longer -h
Basic usage:
-long --longer 
   -h   --help This help information.
How long it is: 4
Remained: "/tmp/.rdmd-314/rdmd-tests.d-0C7A52ECD8084516F3064EED864D6E86/tests"
*/

import std.stdio, std.format, std.getopt;

void main(string[] args) {
  uint s_long = 0;
  auto results = getopt(args,
    std.getopt.config.noBundling,
    std.getopt.config.passThrough,
    "longer|long|l+", &s_long
  );
  if (results.helpWanted) {
    defaultGetoptPrinter("Basic usage:", results.options);
  }
  stderr.writefln("How long it is: %d", s_long);
  stderr.writefln("Remained: %(%s %)", args);
}

Link: https://forum.dlang.org/thread/qxpydyjeyouwltkllfhj@forum.dlang.org

I think that I've got that. There isn't any actual definition of short/long option names. That means if I provide

[code]
"l|long|longer+", &s_long
[/code]

getopt will define 6 variants: -l, --l, -long, --long, -longer, --longer, and here -long, -l and -longer are both short:) Short isn't related to the length of the option name. It's short because there is only one dash (-). This way using "short" is quite confusing.

Regarding the output of the default help message, I should put l at the first position, as in l|long|longer. This is slightly different from examples in the official documentation (https://dlang.org/phobos/std_getopt.html) where you are expected to see long|longer|l+ instead.