Commands should support arguments

[kyrylo]

Currently, there is no way to implement parsing of commands that accept arguments. Let's consider a basic Slop v3 command set:

commands = Slop::Commands.new do
  on 'install'
end

Let's try to parse some input:

commands.parse %w( install geronimo )
#=> ["geronimo"]

The problem with current code is that it doesn't support arguments for install subcommand. Of course, you can save the return value of Commands#parse and use it in your program, but let's have a look at the situation when our command set have more than one command:

commands = Slop::Commands.new do
  on :install
  on :list
end

commands.parse %w( install geronimo )
#=> ["geronimo"]

commands.parse %w( list geronimo )
#=> ["geronimo"]

Both calls return the same value. Given a stroppy user of our CLI tool, it's pretty obvious that we can't tell, which of the subcommands has been executed from program's point of view: install or list?

It seems like the only way to go is to use command options:

commands = Slop::Commands.new do
  on :install do
    on :n, :name
  end

  on :list do
    on :n, :name
  end
end

commands.parse %w( install --name geronimo )
#=> ["--name", "geronimo"]
commands[:install].present? :name
#=> true

commands.parse %w( list --name geronimo )
#=> ["--name", "geronimo"]
commands[:list].present? :name
#=> true

Quite frankly, this pretty verbose and simply sucks.

Possible solutions

Add :with_argument parameter hash to Commands#on

This parameter should be specific for each command.

commands = Slop::Commands.new do
  on :install, :with_argument => true
  on :list
end

commands.parse %w( install geronimo )
#=> ["install", "geronimo"]
commands.present? :install
#=> true
commands.present? :list
#=> false
commands[:list].argument
#=> "geronimo"

Treat one of subcommand options as a default option

commands = Slop::Commands.new do
  on :install do
    as_default(on(:n, :name))
    on :v, :verbose
  end

  on :list
end

commands.parse %w( install --name geronimo )
#=> ["--name", "geronimo"]
commands.parse %w( install geronimo )
#=> ["install", "geronimo"]
commands[:list].argument
#=> "geronimo"

[leejarvis]

Thanks for reporting this. I should have some time tomorrow to look into it a little more.

[leejarvis]

How about something like this:

require 'slop'

opts = Slop::Commands.new do
  on :install
end

opts.parse %w(install geronimo)

p opts.arguments #=> ["geronimo"]

[kyrylo]

Looks good, but still there is no way to tell, which command has been triggered:

opts = Slop::Commands.new do
  on :install
  on :list
end

opts.parse %w(install geronimo)

p opts.arguments #=> ["geronimo"]
# Is this an argument of `install` or maybe `list`?

[leejarvis]

I can't see why you would ever care which command was used. I see something like this:

if opts[:install]
  run_installer(opts.arguments)
end

And just pass around opts.arguments to any sub command you need

[kyrylo]

I don't know, maybe I don't understand something, but this if check doesn't work as you showed in your example. opts[:install] always returns a Slop instance, whatever happens.

opts = Slop::Commands.new do
  on :install
  on :list
end

opts.parse %w(install geronimo)

p opts[:install]
#=> #<Slop {:strict=>false, :help=>false, :banner=>nil, :ignore_case=>false, :autocreate=>false, :arguments=>false, :optional_arguments=>false, :multiple_switches=>true, :longest_flag=>0} []>

p opts[:list]
#=> #<Slop {:strict=>false, :help=>false, :banner=>nil, :ignore_case=>false, :autocreate=>false, :arguments=>false, :optional_arguments=>false, :multiple_switches=>true, :longest_flag=>0} []>

P.S.: Also, keep in mind the situation when we want to pass multiple arguments (like we can do it with options: --install geronimo,banzai,huzzah)

[leejarvis]

Yeah you're right. I think temporarily something like this will have to do:

opts = Slop::Commands.new do
  on :install
  on :list
end

opts.parse %w(install geronimo)

if opts.present?(:install)
  # do something with opts.arguments
end

Which I guess is just short for

if ARGV.first == 'install'
  # ...

That is, I think the command interface probably needs an overhaul but I'd rather plan and spend the time getting it right for Slop v4.

[leejarvis]

Closed by #76