Command-line option parsing

Discussion in 'Ruby' started by Eric J. Roode, Dec 27, 2005.

  1. Greetings,

    I'm new to ruby (from Perl). I notice there are several command-line
    options parsing modules. The two that stuck out were GetoptLong and
    OptionsParser. GetoptLong suffers from being "the same old Getopt".
    OptionsParser claims to be "more advanced and more ruby-like", but has
    extremely poor documentation.

    Are these the best two modules out there? Is there an emerging
    "standard" module? (In Perl, Getopt::Long is by far the most commonly-used
    module).

    (I apologize if this is a FAQ; I read the FAQ and did a google scan of past
    articles. Most of what I found was authors announcing their own options-
    parsing modules).

    Thanks in advance,

    --
    Eric Roode
    Eric J. Roode, Dec 27, 2005
    #1
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  2. Eric J. Roode

    Lou Vanek Guest

    i like CommandLine::OptionParser
    (http://rubyforge.org/docman/view.php/632/170/index.html)
    because it's documentation is better than average as well
    as its features.
    it doesn't appear to be the ruby standard, however, but for
    in-house projects there's a lot to like.


    Eric J. Roode wrote:

    > Greetings,
    >
    > I'm new to ruby (from Perl). I notice there are several command-line
    > options parsing modules. The two that stuck out were GetoptLong and
    > OptionsParser. GetoptLong suffers from being "the same old Getopt".
    > OptionsParser claims to be "more advanced and more ruby-like", but has
    > extremely poor documentation.
    >
    > Are these the best two modules out there? Is there an emerging
    > "standard" module? (In Perl, Getopt::Long is by far the most commonly-used
    > module).
    >
    > (I apologize if this is a FAQ; I read the FAQ and did a google scan of past
    > articles. Most of what I found was authors announcing their own options-
    > parsing modules).
    >
    > Thanks in advance,
    >
    Lou Vanek, Dec 28, 2005
    #2
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  3. Eric J. Roode <> wrote:
    > Greetings,
    >
    > I'm new to ruby (from Perl). I notice there are several
    > command-line options parsing modules. The two that stuck out were
    > GetoptLong and OptionsParser. GetoptLong suffers from being "the
    > same old Getopt". OptionsParser claims to be "more advanced and more
    > ruby-like", but has extremely poor documentation.
    >
    > Are these the best two modules out there? Is there an emerging
    > "standard" module? (In Perl, Getopt::Long is by far the most
    > commonly-used module).


    I used to use GetopLong in the beginning but switched to OptionParser.
    Agreee, the documentation could be better but if you look carefully at the
    example given in RDoc you get pretty much everything you need. I'm not sure
    about a standard parser but my impression was that OptionParser is more
    widely used. But I may be wrong here.

    Kind regards

    robert
    Robert Klemme, Dec 28, 2005
    #3
  4. Eric J. Roode

    Jim Freeze Guest

    ------=_Part_55632_23363128.1135779815810
    Content-Type: text/plain; charset=ISO-8859-1
    Content-Transfer-Encoding: quoted-printable
    Content-Disposition: inline

    On 12/27/05, Lou Vanek <> wrote:
    >
    > i like CommandLine::OptionParser
    > (http://rubyforge.org/docman/view.php/632/170/index.html)
    > because it's documentation is better than average as well
    > as its features.
    > it doesn't appear to be the ruby standard, however, but for
    > in-house projects there's a lot to like.



    Yikes.
    That is old documenetation and the link on Rubyforge was to be replaced eon=
    s
    ago. The new docs are at:
    http://rubyforge.org/docman/view.php/632/233/posted-docs.index.html

    There you will find the option parser docs after Application section. For
    the most part, if you use the CommandLine::Application class, you don't nee=
    d
    to get
    your hands that dirty with CommandLine::OptionParser.


    If you have any questions, just post a question or send me
    a private email. I plan to post a video on the usage this week. Maybe a
    rails like video will generate more interest. :)

    --
    Jim Freeze

    ------=_Part_55632_23363128.1135779815810--
    Jim Freeze, Dec 28, 2005
    #4
  5. Eric J. Roode

    Steve Litt Guest

    On Wednesday 28 December 2005 08:37 am, Robert Klemme wrote:
    > Eric J. Roode <> wrote:
    > > Greetings,
    > >
    > > I'm new to ruby (from Perl). I notice there are several
    > > command-line options parsing modules. The two that stuck out were
    > > GetoptLong and OptionsParser. GetoptLong suffers from being "the
    > > same old Getopt". OptionsParser claims to be "more advanced and more
    > > ruby-like", but has extremely poor documentation.
    > >
    > > Are these the best two modules out there? Is there an emerging
    > > "standard" module? (In Perl, Getopt::Long is by far the most
    > > commonly-used module).

    >
    > I used to use GetopLong in the beginning but switched to OptionParser.
    > Agreee, the documentation could be better but if you look carefully at the
    > example given in RDoc you get pretty much everything you need. I'm not
    > sure about a standard parser but my impression was that OptionParser is
    > more widely used. But I may be wrong here.
    >
    > Kind regards
    >
    > robert


    Does OptionParser come with standard Ruby?

    SteveT

    Steve Litt
    http://www.troubleshooters.com
    Steve Litt, Dec 28, 2005
    #5
  6. Jim Freeze <> wrote:

    > If you have any questions, just post a question or send me
    > a private email. I plan to post a video on the usage this week. Maybe
    > a rails like video will generate more interest. :)


    Will there be stunt scenes with options and a high speed car chase?

    robert
    Robert Klemme, Dec 28, 2005
    #6
  7. Eric J. Roode

    Jim Freeze Guest

    ------=_Part_57353_8112205.1135789737433
    Content-Type: text/plain; charset=ISO-8859-1
    Content-Transfer-Encoding: quoted-printable
    Content-Disposition: inline

    On 12/28/05, Robert Klemme <> wrote:
    >
    >
    > Will there be stunt scenes with options and a high speed car chase?



    It will be action packed. There will be trains, rubies
    and high speed typing! ;)


    --
    Jim Freeze

    ------=_Part_57353_8112205.1135789737433--
    Jim Freeze, Dec 28, 2005
    #7
  8. mathew <> wrote in news:wjosf.9901$9e.8623
    @tornado.texas.rr.com:

    > Eric J. Roode wrote:
    >> GetoptLong suffers from being "the same old Getopt".

    >
    > Well, what do you expect from an options parser? It's pretty much a
    > solved problem, and using the standard getopt algorithms has the
    > advantage that users know what to expect.


    Well... that's not *bad*, but I guess I had expected something a bit more
    ruby-like. Whatever that means. :)


    --
    Eric
    `$=`;$_=\%!;($_)=/(.)/;$==++$|;($.,$/,$,,$\,$",$;,$^,$#,$~,$*,$:,@%)=(
    $!=~/(.)(.).(.)(.)(.)(.)..(.)(.)(.)..(.)......(.)/,$"),$=++;$.++;$.++;
    $_++;$_++;($_,$\,$,)=($~.$"."$;$/$%[$?]$_$\$,$:$%[$?]",$"&$~,$#,);$,++
    ;$,++;$^|=$";`$_$\$,$/$:$;$~$*$%[$?]$.$~$*${#}$%[$?]$;$\$"$^$~$*.>&$=`
    Eric J. Roode, Dec 28, 2005
    #8
  9. "Robert Klemme" <> wrote in
    news::

    > I used to use GetopLong in the beginning but switched to OptionParser.
    > Agreee, the documentation could be better but if you look carefully at
    > the example given in RDoc you get pretty much everything you need.
    > I'm not sure about a standard parser but my impression was that
    > OptionParser is more widely used. But I may be wrong here.


    I disagree about the example being all you need.

    Here's the first option in the example:

    # Mandatory argument.
    opts.on("-r", "--require LIBRARY",
    "Require the LIBRARY before executing your script") do |lib|
    options.library << lib
    end

    I am new to ruby, so I don't know what "options.library << lib" means. I
    thought that that introduced a here-doc string.

    The second example:

    # Optional argument; multi-line description.
    opts.on("-i", "--inplace [EXTENSION]",
    "Edit ARGV files in place",
    " (make backup if EXTENSION supplied)") do |ext|
    ...

    It took me a lot of staring at the code before it dawned on me that it
    was the *brackets* that made it an optional argument.

    The final example:

    # Another typical switch to print the version.
    opts.on_tail("--version", "Show version") do
    puts OptionParser::Version.join('.')
    exit
    end

    I can't figure out how the on_tail method differs from the on method or
    the on_head method. Reading the source isn't helping. The example
    sucks.

    The previous example has this comment:

    # No argument, shows at tail. This will print an options summary.

    "Shows at tail"??

    At the end of the parse() method (and why is it self.parse, not just
    parse?), there is this:

    opts.parse!(args)

    I can't tell what function that performs for the class.

    I can't tell how to make an option mandatory, how to configure it so that
    some options require certain others or conflict with certain others.

    It looks like a fine, powerful module. But its lack of documentation
    makes it pretty much useless for anyone who doesn't already know how to
    use it.

    I come from the Perl world. You simply do not release a module to Perl's
    CPAN unless it is thoroughly documented. The vast majority of CPAN
    modules have quite good documentation -- or at least, thorough
    documentation. I'm quite surprised to find that the situation is so
    different in the ruby world.

    --
    Eric
    `$=`;$_=\%!;($_)=/(.)/;$==++$|;($.,$/,$,,$\,$",$;,$^,$#,$~,$*,$:,@%)=(
    $!=~/(.)(.).(.)(.)(.)(.)..(.)(.)(.)..(.)......(.)/,$"),$=++;$.++;$.++;
    $_++;$_++;($_,$\,$,)=($~.$"."$;$/$%[$?]$_$\$,$:$%[$?]",$"&$~,$#,);$,++
    ;$,++;$^|=$";`$_$\$,$/$:$;$~$*$%[$?]$.$~$*${#}$%[$?]$;$\$"$^$~$*.>&$=`
    Eric J. Roode, Dec 28, 2005
    #9
  10. Eric J. Roode

    Jim Freeze Guest

    ------=_Part_61088_27178231.1135816236587
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    Hi Eric

    You may want to give CommandLine a try.
    From the examples you give, this is how I would write an app:

    require 'rubygems'
    require 'commandline'

    class MyApp < CommandLine::Application
    def initialize
    # Mandatory argument
    option :names =3D> %w(--require -r),
    :eek:pt_description =3D> "Require the LIBRARY "+
    "before executing your script",
    :arg_description =3D> "LIBRARY",
    :eek:pt_found =3D> get_arg,
    :eek:pt_not_found =3D> required

    option :names =3D> %w(--inplace -i),
    :arity =3D> [0,1],
    :eek:pt_description =3D> "Edit ARGV files in place",
    :arg_description =3D> "[EXTENSION]",
    :eek:pt_found =3D> get_arg,
    end

    def main
    #put your code here
    p opts
    end
    end#class MyApp

    I don't know what #on_tail does either.


    --
    Jim Freeze

    ------=_Part_61088_27178231.1135816236587--
    Jim Freeze, Dec 29, 2005
    #10
  11. Eric J. Roode wrote:
    > mathew <> wrote in news:wjosf.9901$9e.8623
    > @tornado.texas.rr.com:
    >
    > > Eric J. Roode wrote:
    > >> GetoptLong suffers from being "the same old Getopt".

    > >
    > > Well, what do you expect from an options parser? It's pretty much a
    > > solved problem, and using the standard getopt algorithms has the
    > > advantage that users know what to expect.

    >
    > Well... that's not *bad*, but I guess I had expected something a bit more
    > ruby-like. Whatever that means. :)


    That's a good expectation to have.

    You mention OptionParser has poor documentation. While it's not
    complete, I find the example at [1] is quite adequate.

    [1]
    http://ruby-doc.org/stdlib/libdoc/optparse/rdoc/classes/OptionParser.html

    Gavin
    Gavin Sinclair, Dec 29, 2005
    #11
  12. Eric J. Roode wrote:
    >
    > I disagree about the example being all you need.


    Please disregard my other reply in this thread. Your points are
    perfectly valid and I'll try to improve the documentation.

    > Here's the first option in the example:
    >
    > # Mandatory argument.
    > opts.on("-r", "--require LIBRARY",
    > "Require the LIBRARY before executing your script") do |lib|
    > options.library << lib
    > end
    >
    > I am new to ruby, so I don't know what "options.library << lib" means. I
    > thought that that introduced a here-doc string.


    The documentation's not at fault here: knowledge of Ruby is assumed :)

    > The second example:
    >
    > # Optional argument; multi-line description.
    > opts.on("-i", "--inplace [EXTENSION]",
    > "Edit ARGV files in place",
    > " (make backup if EXTENSION supplied)") do |ext|
    > ...
    >
    > It took me a lot of staring at the code before it dawned on me that it
    > was the *brackets* that made it an optional argument.


    That will be easy to point out in the docs. Thanks.

    > The final example:
    >
    > # Another typical switch to print the version.
    > opts.on_tail("--version", "Show version") do
    > puts OptionParser::Version.join('.')
    > exit
    > end
    >
    > I can't figure out how the on_tail method differs from the on method or
    > the on_head method. Reading the source isn't helping. The example
    > sucks.


    It means to show the "--version" option at the end (the "tail") of the
    options list.

    >
    > At the end of the parse() method (and why is it self.parse, not just
    > parse?), there is this:
    >
    > opts.parse!(args)
    >
    > I can't tell what function that performs for the class.


    Hopefully I can clear this up. The difference between parse and parse!
    is that parse! swallows ARGV.

    > I can't tell how to make an option mandatory, how to configure it so that
    > some options require certain others or conflict with certain others.


    A "mandatory option" is a contradiction :) You need to test for the
    presence of an option in your own code.

    > I come from the Perl world. You simply do not release a module to Perl's
    > CPAN unless it is thoroughly documented. The vast majority of CPAN
    > modules have quite good documentation -- or at least, thorough
    > documentation. I'm quite surprised to find that the situation is so
    > different in the ruby world.


    While not disagreeing in the least, I bet there are plenty of
    badly-documented Perl modules, but they're not the often-used ones, so
    they don't detract from the "Perl modules are well documented" meme.

    Ruby is certainly worse, though!

    Gavin
    Gavin Sinclair, Dec 29, 2005
    #12
  13. Gavin Sinclair wrote:

    <snip>

    > While not disagreeing in the least, I bet there are plenty of
    > badly-documented Perl modules, but they're not the often-used ones, so
    > they don't detract from the "Perl modules are well documented" meme.
    >
    > Ruby is certainly worse, though!
    >
    > Gavin


    How's that shell documentation coming along?

    Dan
    Daniel Berger, Dec 29, 2005
    #13
  14. Eric J. Roode <> wrote:
    > "Robert Klemme" <> wrote in
    > news::
    >
    >> I used to use GetopLong in the beginning but switched to
    >> OptionParser. Agreee, the documentation could be better but if you
    >> look carefully at the example given in RDoc you get pretty much
    >> everything you need. I'm not sure about a standard parser but my
    >> impression was that OptionParser is more widely used. But I may be
    >> wrong here.

    >
    > I disagree about the example being all you need.


    It seems to me that your posting pretty much confirms what I said: I didn't
    claim it's "all you need" but that it gets you pretty far, if you "look
    carefully". :) Admittedly it's not so easy for someone new to Ruby...

    Kind regards

    robert
    Robert Klemme, Dec 29, 2005
    #14
  15. Daniel Berger wrote:

    > How's that shell documentation coming along?


    Not too well, just yet!

    Gavin
    Gavin Sinclair, Dec 29, 2005
    #15
  16. > A "mandatory option" is a contradiction :) You need to test for the
    > presence of an option in your own code.


    This is a fair point, but for complex command lines we sometimes really
    need options that are not optional. For example, I'm working on a ruby
    xmltv-like scraper, that has a bunch of regular options, plus essential
    arguments like --config CONFIG_FILE and --scraper SCRAPER_FILE for
    specifying files that are necessary.

    I want to use options for these rather than arguments because they are
    both files and I prefer that the user specify the option --config or
    --scraper rather than having to get the order of them right on the
    command line.

    So you see, I need an "option" that is mandatory in addition to it
    having a mandatory argument.

    Sure I could do it in my own code - but given this is a common case I'm
    tempted to extend OptionParser to do it so that I can get at the option
    description when I report that its missing you see? This is why it
    should probably be a feature of OptionParser - to tie the error message
    to the switch that's missing. I don't think I can be bothered wading
    into that code myself, so I guess I'll do something a little hackier -
    test my options and repeat the option descriptions.

    But how about it Gavin?

    Also - even if you don't - you should probably clearly document the
    fact this isn't available. The frequent use of "MANDATORY" in the
    example led me and probably many others to think it was bug that my
    mandatory arguments weren't reported as missing. It took me a while to
    realize that the word "argument" was key here. It also took me a while
    to realize that the square brackets were important.

    --
    Posted via http://www.ruby-forum.com/.
    Rover Rhubarb, May 3, 2007
    #16
  17. On 5/3/07, Rover Rhubarb <> wrote:
    > > A "mandatory option" is a contradiction :) You need to test for the
    > > presence of an option in your own code.

    >
    > This is a fair point, but for complex command lines we sometimes really
    > need options that are not optional. For example, I'm working on a ruby
    > xmltv-like scraper, that has a bunch of regular options, plus essential
    > arguments like --config CONFIG_FILE and --scraper SCRAPER_FILE for
    > specifying files that are necessary.
    >
    > I want to use options for these rather than arguments because they are
    > both files and I prefer that the user specify the option --config or
    > --scraper rather than having to get the order of them right on the
    > command line.
    >
    > So you see, I need an "option" that is mandatory in addition to it
    > having a mandatory argument.
    >
    > Sure I could do it in my own code - but given this is a common case I'm
    > tempted to extend OptionParser to do it so that I can get at the option
    > description when I report that its missing you see? This is why it
    > should probably be a feature of OptionParser - to tie the error message
    > to the switch that's missing. I don't think I can be bothered wading
    > into that code myself, so I guess I'll do something a little hackier -
    > test my options and repeat the option descriptions.
    >
    > But how about it Gavin?
    >
    > Also - even if you don't - you should probably clearly document the
    > fact this isn't available. The frequent use of "MANDATORY" in the
    > example led me and probably many others to think it was bug that my
    > mandatory arguments weren't reported as missing. It took me a while to
    > realize that the word "argument" was key here. It also took me a while
    > to realize that the square brackets were important.


    I agree completely.

    The wording should be: mandatory option argument, not option.

    And yes, it makes sense to /also/ make some options mandatory.

    --
    Felipe Contreras
    Felipe Contreras, May 3, 2007
    #17
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