Hello. I'm just getting into D (literally writing my first program), and I can't figure out how to do this with getopt:

I want to have the option --log, which will enable logging (set a bool variable to true). However, I want the program to also accept --log=filename to allow the user to define custom log file. If --log is used without filename, a default file will be used.

I tried this:

getopt(args,
    "log", &log,
    "log", &logFile);

Passing just --log to the program works fine, the boolean is set to true. However, using --log=test.log throws an exception, and seemingly getopt expects either true or false.

How would I go about implementing this without creating another option like --log-file for custom file name?

On Friday, 13 December 2013 at 01:51:25 UTC, Ithy wrote:
> Hello. I'm just getting into D (literally writing my first program), and I can't figure out how to do this with getopt:
>
> I want to have the option --log, which will enable logging (set a bool variable to true). However, I want the program to also accept --log=filename to allow the user to define custom log file. If --log is used without filename, a default file will be used.
>
> I tried this:
>
> getopt(args,
>     "log", &log,
>     "log", &logFile);
>
> Passing just --log to the program works fine, the boolean is set to true. However, using --log=test.log throws an exception, and seemingly getopt expects either true or false.
>
> How would I go about implementing this without creating another option like --log-file for custom file name?

That doesn't seem possible with getopt.

I would use std.getopt.config.passThrough and then deal with the "log" option manually afterwards.

On Fri, Dec 13, 2013 at 10:46:57AM +0100, John Colvin wrote:
> On Friday, 13 December 2013 at 01:51:25 UTC, Ithy wrote:
> >Hello. I'm just getting into D (literally writing my first program), and I can't figure out how to do this with getopt:
> >
> >I want to have the option --log, which will enable logging (set a bool variable to true). However, I want the program to also accept --log=filename to allow the user to define custom log file. If --log is used without filename, a default file will be used.
> >
> >I tried this:
> >
> >getopt(args,
> >    "log", &log,
> >    "log", &logFile);
> >
> >Passing just --log to the program works fine, the boolean is set to true. However, using --log=test.log throws an exception, and seemingly getopt expects either true or false.
> >
> >How would I go about implementing this without creating another option like --log-file for custom file name?
> 
> That doesn't seem possible with getopt.
> 
> I would use std.getopt.config.passThrough and then deal with the "log" option manually afterwards.

I would file an enhancement request in the bugtracker. This is a pretty common idiom in command-line parsing.

	http://d.puremagic.com/issues/


T

-- 
We are in class, we are supposed to be learning, we have a teacher... Is it too much that I expect him to teach me??? -- RL