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From: Jacob Sparre Andersen <sparre@nbi.dk>
Newsgroups: comp.lang.ada
Subject: ANN: Command Line Parser Generator
Date: Thu, 20 Aug 2015 15:15:33 +0200
Organization: JSA Research & Innovation
Message-ID: <87io8aje2y.fsf@adaheads.sparre-andersen.dk>
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Xref: news.eternal-september.org comp.lang.ada:27524
Date: 2015-08-20T15:15:33+02:00
List-Id: <comp.lang.ada>

I would like to announce that I have brought my command line parser
generator[1] to (what I assume is) a usable state.

Instead of manually implementing command line parsing using some
library, you can collect all the ways your program can be called as
procedures in a package.

A simple example:

   package Filter is
      procedure Show_Help (Help : Boolean);
      --  Shows the usage instructions (no matter the value of 'Help').

      procedure Process (Source_File : String := "";
                         Target_File : String := "");
      --  Empty file names are mapped to respectively 'Standard_Input'
      --  and 'Standard_Output'.
   end Filter;

Running (yes, I need a shorter name for it):

   command_line_parser_generator-run Filter

in the directory containing 'filter.ads' generates
'generated/filter-driver.adb', which when compiled transforms command
line arguments into procedure calls like this:

   --help                -> Filter.Show_Help (Help => True);
   --source_file=data    -> Filter.Process (Source_File => "data");
   --target_file=out     -> Filter.Process (Target_File => "out");
   --source_file=data --target_file=out
                         -> Filter.Process (Source_File => "data",
                                            Target_File => "out");

There are currently two known issues with the tool [2]:

a) The tool assumes that all non-String types have a 'Value attribute,
   without checking if this is the case.

b) The tool doesn't check if the type of a formal parameter has a
   primitive Value function (which should override the 'Value
   attribute).

Enjoy!

Jacob

[1] http://repositories.jacob-sparre.dk/command-line-parser-generator/wiki/Home
[2] http://repositories.jacob-sparre.dk/command-line-parser-generator/issues?status=new&status=open
-- 
"In Ada you model the problem space, not the solution space."
                                                     -- Robert I. Eachus