Question

I have a Ruby app which uses readline with command completion.

After the first string (the command) was typed, I would like to be able to complete its arguments. The arguments list should be based on the chosen command.

Does someone have a quick example?

These are the commands:

COMMANDS = [
  'collect', 'watch'
].sort

COLLECT = [
  'stuff', 'otherstuff'
].sort

comp = proc do |s| 
  COMMANDS.grep( /^#{Regexp.escape(s)}/ )        
end

Readline.completion_proc = comp

Each time I press TAB, the proc block is executed and a command from the COMMANDS array is matched.
After one of the commands was fully matched I would like to start searching for the argument only in the COLLECT array.

Answer 1

After thinking a while, the solution was very simple:

comp = proc do |s| 
  if Readline.line_buffer =~ /^.* /
    COLLECT.grep( /^#{Regexp.escape(s)}/ ) 
  else
    COMMANDS.grep( /^#{Regexp.escape(s)}/ ) 
  end
end

Now I just need to turn it into something more flexible/usable.