From: Robert Klemme <bob.news@...>
Date: 2004-11-08T18:58:41+09:00
Subject: Re: From getoptlong to optparse

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"Massimiliano Mirra - bard" <mmirra@libero.REMOVETHIS.it> schrieb im
Newsbeitrag news:87k6sxr9zo.fsf@prism.localnet...
> "Robert Klemme" <bob.news@gmx.net> writes:
>
> >> >>     while ARGV.first =~ /^-/
> >> >>       opt, arg = opts.get
> >> >>       case opt
> >> >>       when "--host"
> >> >>         config["host"] = arg
> >> >>       when "--port"
> >> >>         config["port"] = arg.to_i
> >> >>       end
> >> >>     end
>
> >> Not exactly.  I need to stop parsing when a special command is seen.
> >> "--host" and "--port" in the above example might appear in a
different
> >> order or not appear at all, so they're not reliable.
> >
> > Do you mean the problem is that you need to stop when a command is
seen
> > *and* this command can occur anywhere, i.e. also behind an option with
an
> > optional argument?
>
> Yes and no.  Yes: this command can occur anywhere after one or more
> options.  No: I have no options with optional arguments so far, so I
> haven't dealt with this case which I suspect to be more complex.

Certainly. :-)

> >> > Evaluate the first non option, this is your next command.
> >>
> >> This needs to go hand in hand with option parsing.  Consider this:
> >>
> >>   $ prog --opt1 arg1 --opt2 stuff --blah
> >>
> >> Is `stuff' a subcommand or opt2's argument? That depends on opt2's
> >> definition (which in GetoptLong means NO_ARGUMENT or
> >> REQUIRED_ARGUMENT).
> >
> > You have the same (or finer) level of control for option arguments in
> > optparse, too.
>
> The kind of control I am trying to get was not given by GetoptLong per
> se, but by the `while ARGV.first =~ /^-/', which breaks down parsing
> in chunks where the subcommand can be detected.
>
> >>  Then again, if you're thinking that things get
> >> muddy when opt2 has an optional argument, I do agree...
> >
> > Yes, they certainly get muddy at this point.  They get as muddy as to
be
> > undecidable if you have a command that is also a valid optional
argument
> > of an option.  You can't decide what it is other than defining a
priority
> > for the resolution of this ambiguity.
>
> Yes.  Or just disallowing optional arguments for generic options, the
> need hasn't arisen so far and I doubt it will at least for this
application.

Yep, that works as well.

> >> > Eat it and go to the first step only now remembering that options
> >> > are stored for this command.  Repeat until there are no more args
> >> > left or the first non option is not a command (i.e. file name,
> >> > ignorable or whatever).
> >>
> >> How is this different from the ARGV loop above?
> >
> > You have two nested loops, one of them is hidden in optparse.
>
> Sorry but I still can't make a picture of what you are suggesting.
> Would you mind sketching a couple of lines of pseudocode?

Hm...  I'll attache a modified version of the optparse example which
yields this output

10:55:10 [ruby]: ruby optparse-example-2.rb --verbose cmd1 -i foo
<OpenStruct encoding="utf8" transfer_type=:auto verbose=true library=[]
inplace=false>
<OpenStruct extension=".foo" encoding="utf8" transfer_type=:auto
verbose=false library=[] inplace=true>
10:55:38 [ruby]:

Of course, additional handling has to be done for file name arguments but
I hope you get the picture.

Kind regards

    robert

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#!/usr/bin/ruby=0A=
=0A=
  require 'optparse'=0A=
  require 'optparse/time'=0A=
  require 'ostruct'=0A=
  require 'pp'=0A=
=0A=
ENV['POSIXLY_CORRECT']=3D'1'=0A=
=0A=
  class OptparseExample=0A=
=0A=
    CODES =3D %w[iso-2022-jp shift_jis euc-jp utf8 binary]=0A=
    CODE_ALIASES =3D { "jis" =3D> "iso-2022-jp", "sjis" =3D> "shift_jis" =
}=0A=
=0A=
    #=0A=
    # Return a structure describing the options.=0A=
    #=0A=
    def self.parse(args)=0A=
      # The options specified on the command line will be collected in =
*options*.=0A=
      # We set default values here.=0A=
      options =3D OpenStruct.new=0A=
      options.library =3D []=0A=
      options.inplace =3D false=0A=
      options.encoding =3D "utf8"=0A=
      options.transfer_type =3D :auto=0A=
      options.verbose =3D false=0A=
=0A=
      global_opts =3D OptionParser.new do |global_opts|=0A=
        global_opts.banner =3D "Usage: example.rb [options]"=0A=
=0A=
        global_opts.separator ""=0A=
        global_opts.separator "Specific options:"=0A=
=0A=
        # Mandatory argument.=0A=
        global_opts.on("-r", "--require LIBRARY",=0A=
                "Require the LIBRARY before executing your script") do =
|lib|=0A=
          options.library << lib=0A=
        end=0A=
=0A=
        # Optional argument; multi-line description.=0A=
        global_opts.on("-i", "--inplace [EXTENSION]",=0A=
                "Edit ARGV files in place",=0A=
                "  (make backup if EXTENSION supplied)") do |ext|=0A=
          options.inplace =3D true=0A=
          options.extension =3D ext || ''=0A=
          options.extension.sub!(/\A\.?(?=3D.)/, ".")  # Ensure =
extension begins with dot.=0A=
        end=0A=
=0A=
        # Cast 'delay' argument to a Float.=0A=
        global_opts.on("--delay N", Float, "Delay N seconds before =
executing") do |n|=0A=
          options.delay =3D n=0A=
        end=0A=
=0A=
        # Cast 'time' argument to a Time object.=0A=
        global_opts.on("-t", "--time [TIME]", Time, "Begin execution at =
given time") do |time|=0A=
          options.time =3D time=0A=
        end=0A=
=0A=
        # Cast to octal integer.=0A=
        global_opts.on("-F", "--irs [OCTAL]", OptionParser::OctalInteger,=0A=
                "Specify record separator (default \\0)") do |rs|=0A=
          options.record_separator =3D rs=0A=
        end=0A=
=0A=
        # List of arguments.=0A=
        global_opts.on("--list x,y,z", Array, "Example 'list' of =
arguments") do |list|=0A=
          options.list =3D list=0A=
        end=0A=
=0A=
        # Keyword completion.  We are specifying a specific set of =
arguments (CODES=0A=
        # and CODE_ALIASES - notice the latter is a Hash), and the user =
may provide=0A=
        # the shortest unambiguous text.=0A=
        code_list =3D (CODE_ALIASES.keys + CODES).join(',')=0A=
        global_opts.on("--code CODE", CODES, CODE_ALIASES, "Select =
encoding",=0A=
                "  (#{code_list})") do |encoding|=0A=
          options.encoding =3D encoding=0A=
        end=0A=
=0A=
        # Optional argument with keyword completion.=0A=
        global_opts.on("--type [TYPE]", [:text, :binary, :auto],=0A=
                "Select transfer type (text, binary, auto)") do |t|=0A=
          options.transfer_type =3D t=0A=
        end=0A=
=0A=
        # Boolean switch.=0A=
        global_opts.on("-v", "--[no-]verbose", "Run verbosely") do |v|=0A=
          options.verbose =3D v=0A=
        end=0A=
=0A=
        global_opts.separator ""=0A=
        global_opts.separator "Common options:"=0A=
=0A=
        # No argument, shows at tail.  This will print an options =
summary.=0A=
        # Try it and see!=0A=
        global_opts.on_tail("-h", "--help", "Show this message") do=0A=
          puts global_opts=0A=
          exit=0A=
        end=0A=
=0A=
        # Another typical switch to print the version.=0A=
        global_opts.on_tail("--version", "Show version") do=0A=
          puts OptionParser::Version.join('.')=0A=
          exit=0A=
        end=0A=
      end=0A=
=0A=
      cmd1_options =3D OpenStruct.new=0A=
      cmd1_options.library =3D []=0A=
      cmd1_options.inplace =3D false=0A=
      cmd1_options.encoding =3D "utf8"=0A=
      cmd1_options.transfer_type =3D :auto=0A=
      cmd1_options.verbose =3D false=0A=
=0A=
      cmd1_opts =3D OptionParser.new do |cmd1_opts|=0A=
        cmd1_opts.banner =3D "Usage: example.rb [cmd1_options]"=0A=
=0A=
        cmd1_opts.separator ""=0A=
        cmd1_opts.separator "Specific cmd1_options:"=0A=
=0A=
        # Mandatory argument.=0A=
        cmd1_opts.on("-r", "--require LIBRARY",=0A=
                "Require the LIBRARY before executing your script") do =
|lib|=0A=
          cmd1_options.library << lib=0A=
        end=0A=
=0A=
        # Optional argument; multi-line description.=0A=
        cmd1_opts.on("-i", "--inplace [EXTENSION]",=0A=
                "Edit ARGV files in place",=0A=
                "  (make backup if EXTENSION supplied)") do |ext|=0A=
          cmd1_options.inplace =3D true=0A=
          cmd1_options.extension =3D ext || ''=0A=
          cmd1_options.extension.sub!(/\A\.?(?=3D.)/, ".")  # Ensure =
extension begins with dot.=0A=
        end=0A=
=0A=
        # Cast 'delay' argument to a Float.=0A=
        cmd1_opts.on("--delay N", Float, "Delay N seconds before =
executing") do |n|=0A=
          cmd1_options.delay =3D n=0A=
        end=0A=
=0A=
        # Cast 'time' argument to a Time object.=0A=
        cmd1_opts.on("-t", "--time [TIME]", Time, "Begin execution at =
given time") do |time|=0A=
          cmd1_options.time =3D time=0A=
        end=0A=
=0A=
        # Cast to octal integer.=0A=
        cmd1_opts.on("-F", "--irs [OCTAL]", OptionParser::OctalInteger,=0A=
                "Specify record separator (default \\0)") do |rs|=0A=
          cmd1_options.record_separator =3D rs=0A=
        end=0A=
=0A=
        # List of arguments.=0A=
        cmd1_opts.on("--list x,y,z", Array, "Example 'list' of =
arguments") do |list|=0A=
          cmd1_options.list =3D list=0A=
        end=0A=
=0A=
        # Keyword completion.  We are specifying a specific set of =
arguments (CODES=0A=
        # and CODE_ALIASES - notice the latter is a Hash), and the user =
may provide=0A=
        # the shortest unambiguous text.=0A=
        code_list =3D (CODE_ALIASES.keys + CODES).join(',')=0A=
        cmd1_opts.on("--code CODE", CODES, CODE_ALIASES, "Select =
encoding",=0A=
                "  (#{code_list})") do |encoding|=0A=
          cmd1_options.encoding =3D encoding=0A=
        end=0A=
=0A=
        # Optional argument with keyword completion.=0A=
        cmd1_opts.on("--type [TYPE]", [:text, :binary, :auto],=0A=
                "Select transfer type (text, binary, auto)") do |t|=0A=
          cmd1_options.transfer_type =3D t=0A=
        end=0A=
=0A=
        # Boolean switch.=0A=
        cmd1_opts.on("-v", "--[no-]verbose", "Run verbosely") do |v|=0A=
          cmd1_options.verbose =3D v=0A=
        end=0A=
=0A=
        cmd1_opts.separator ""=0A=
        cmd1_opts.separator "Common cmd1_options:"=0A=
=0A=
        # No argument, shows at tail.  This will print an cmd1_options =
summary.=0A=
        # Try it and see!=0A=
        cmd1_opts.on_tail("-h", "--help", "Show this message") do=0A=
          puts cmd1_opts=0A=
          exit=0A=
        end=0A=
=0A=
        # Another typical switch to print the version.=0A=
        cmd1_opts.on_tail("--version", "Show version") do=0A=
          puts OptionParser::Version.join('.')=0A=
          exit=0A=
        end=0A=
      end=0A=
=0A=
      global_opts.parse!(args)=0A=
=0A=
      until args.empty?=0A=
        cmd =3D args.shift=0A=
        case cmd=0A=
          when "cmd1"=0A=
            cmd1_opts.parse!(args)=0A=
          else=0A=
            raise "Unknown command: #{cmd}"=0A=
        end=0A=
      end=0A=
=0A=
      [options, cmd1_options]=0A=
    end  # parse()=0A=
=0A=
  end  # class OptparseExample=0A=
=0A=
  options, cmd1_options =3D OptparseExample.parse(ARGV)=0A=
  pp options=0A=
  pp cmd1_options=0A=
=0A=

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