From: Phrogz <gavin@...>
Date: 2007-01-11T06:00:14+09:00
Subject: Re: Command Line Argument Processing

robertlafe...@comcast.net wrote:
> What is everyone using (other than manually) to process command line arguments?
> I have looked at optparse (OptionParser) but it is not well documented.  Is there
> something better?  Or is there better documentation for optparse out there?

Like you, I was confused by the documentation for optparse and
getoptlong. So, for a while, I was using the Usage gem:
http://rubyforge.org/projects/usage/

You have to install the gem and then look at its documentation to
figure out how to use it, but I found it reasonably easy. Eventually,
though, I got tired of some if its limitations and started writing my
own template code (sample follows). It's certainly a manual process,
but I liked feeling the wind in my hair.


USAGE = <<ENDUSAGE
Usage:
   findfile  [-d max_depth] [-a] [-c] [-i] name_regexp [content_regexp]
   -d,--depth        the maximum depth to recurse to (defaults to no
limit)
   -a,--showall      with content_regexp, show every match per file
                     (defaults to only show the first-match per file)
   -c,--usecase      with content_regexp, use case-sensitive matching
                     (defaults to case-insensitive)
   -i,--includedirs  also find directories matching name_regexp
                     (defaults to files only; incompatible with
content_regexp)
   -h,--help         show some help examples
ENDUSAGE

EXAMPLES = <<ENDEXAMPLES

Examples:
   findfile foo
   # Print the path to all files with 'foo' in the name

   findfile -i foo
   # Print the path to all files and directories with 'foo' in the name

   findfile js$
   # Print the path to all files whose name ends in "js"

   findfile js$ vector
   # Print the path to all files ending in "js" with "Vector" or
"vector"
   # (or "vEcTOr", "VECTOR", etc.) in the contents, and print some of
the
   # first line that has that content.

   findfile js$ -c Vector
   # Like above, but must match exactly "Vector" (not 'vector' or
'VECTOR').

   findfile . vector -a
   # Print the path to every file with "Vector" (any case) in it
somewhere
   # printing every line in those files (with line numbers) with that
content.

   findfile -d 0 .
   # Print the path to every file that is in the current directory.

   findfile -d 1 .
   # Print the path to every file that is in the current directory or
any
   # of its child directories (but no subdirectories of the children).
ENDEXAMPLES

ARGS = {}
UNFLAGGED_ARGS = [ :name_regexp, :content_regexp ]
next_arg = UNFLAGGED_ARGS.first
ARGV.each{ |arg|
   case arg
     when '-d','--depth'
       next_arg = :max_depth
     when '-a','--showall'
       ARGS[:showall] = true
     when '-c','--usecase'
       ARGS[:usecase] = true
     when '-i','--includedirs'
       ARGS[:includedirs] = true
     when '-h','--help'
       ARGS[:help] = true
     else
       if next_arg
         if next_arg==:max_depth
           arg = arg.to_i + 1
         end
         ARGS[next_arg] = arg
         UNFLAGGED_ARGS.delete( next_arg )
       end
       next_arg = UNFLAGGED_ARGS.first
   end
}

if ARGS[:help] or !ARGS[:name_regexp]
   puts USAGE
   puts EXAMPLES if ARGS[:help]
   exit
end