getopt helpWanted
wobbles via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Thu Apr 30 00:25:56 PDT 2015
On Wednesday, 29 April 2015 at 22:02:29 UTC, novice2 wrote:
> Hello.
>
> Help me please to understand, how to show usage help to user,
> who enter wrong options?
> For example, user not provided required filename.
> I want to show error message, and program usage help text.
> But likely getopt don't provide help text until valid options
> will be parsed.
>
> Reduced code:
> ///////////////
> import std.stdio: writefln;
> import std.getopt;
>
> void main (string[] args)
> {
> string fname;
> GetoptResult helpInfo;
>
> try
> {
> helpInfo = getopt(
> args,
> std.getopt.config.required, "file|f", "File name",
> &fname);
>
> writefln("Options parsed: fname=%s", fname);
> }
> catch(Exception e)
> {
> writefln("\nERROR: %s", e.msg);
> defaultGetoptPrinter("Program usage:", helpInfo.options);
> }
> }
> ///////////////
>
> Output:
> ERROR: Required option file|fwas not supplied
> Program usage:
Also, I suggest you look at docopt:
http://code.dlang.org/packages/docopt
It makes the whole parsing of CLI arguments very nice and easy.
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