Using ruby's OptionParser to parse sub-commands

ruby optparse optionparser
rampion picture rampion · Apr 28, 2010 · Viewed 7.1k times · Source

I'd like to be able to use ruby's OptionParser to parse sub-commands of the form

COMMAND [GLOBAL FLAGS] [SUB-COMMAND [SUB-COMMAND FLAGS]]

like:

git branch -a
gem list foo

I know I could switch to a different option parser library (like Trollop), but I'm interested in learning how to do this from within OptionParser, since I'd like to learn the library better.

Any tips?

Answer

rampion picture rampion · Apr 29, 2010

Figured it out. I need to use OptionParser#order!. It will parse all the options from the start of ARGV until it finds a non-option (that isn't an option argument), removing everything it processes from ARGV, and then it will quit.

So I just need to do something like:

global = OptionParser.new do |opts|
  # ...
end
subcommands = { 
  'foo' => OptionParser.new do |opts|
     # ...
   end,
   # ...
   'baz' => OptionParser.new do |opts|
     # ...
   end
 }

 global.order!
 subcommands[ARGV.shift].order!

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