Re: [Seqan-dev] ArgParseArgument list allowing zero or more items?

[Rahn, René <rene.maerker@fu-berlin.de>]

Hi Bernie, 

thank you very much for writing us. 

I'd like you to raise such questions on the issue site on our github page: https://github.com/seqan/seqan/issues.

The mailing list is not-so-up-to-date anymore, and we will probably use this mailing list merely as a news feeder in the future to inform you about new releases or training courses.

Thank you very much for you understanding.

Kind regards,

René

On 10 Jul 2016, at 08:35, Bernard James Pope <bjpope@unimelb.edu.au> wrote:

Hi SEQAN devs,

I'm writing a program which accepts zero or more FASTA files on the command line, as positional arguments.

If zero files are specified, then it will default to reading from standard input.

I want to write a Seqan argument parser to capture this behaviour. However, I seem stuck with a solution that requires at least one file to be specified.

Here's a sketch of what I have:

  ArgumentParser parser(PROGRAM_NAME);
  addOption(parser, ArgParseOption("f", "foo", "Silly example", ArgParseArgument::INTEGER, "INT"));

  addArgument(parser, ArgParseArgument(ArgParseArgument::STRING, "FASTA_FILE", true));

  ArgumentParser::ParseResult res = parse(parser, argc, argv);

Notice that isListArgument is set to true.

However, when I run my program, and specify zero positional arguments (but some other option arguments), e.g.

   $ myprogram -foo 0

I get the error:

   Not enough arguments were provided.

Is there a way to achieve what I want to do?

I thought I might be able to default the ArgParseArgument to be an empty vector somehow, but couldn't get that to work.

If anyone has used the Python ArgumentParser before, the behaviour I want to emulate is the ability to specify nargs='*'

Cheers,
Bernie
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René Rahn

Ph.D. Student (de.NBI - CIBI)

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Tel:  (+49) 30 838 75137

Mail: rene.rahn@fu-berlin.de

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Institute of Computer Science

Algorithmic Bioinformatics (ABI)

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14195 Berlin

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