Crystal port of Clik

clik.cr

  def cli(opts : Hash(String,Proc))
    cli(ARGV.dup, opts)
  end

  def cli(argv : Array(String), opts : Hash(String,Proc))
    args = [] of String

    # Split option aliases.
    h = {} of String => ->
    opts.each do |k,v|
      k.to_s.split(/\s+/).each { |o| h[o] = v }
    end
    opts = h

    # Convert single dash flags into multiple flags.
    a = [] of String
    argv.each do |v|
      if v[0,1] == "-" && v[1,1] != "-"
        a.concat(v[1..-1].chars.map{|c| "-#{c}"})
      else
        a << v
      end
    end
    argv = a

    while argv.any?
      item = argv.shift
      flag = opts[item]

      if flag
        # Work around lambda semantics in 1.8.7.
        arity = [flag.arity, 0].max

        # Raise if there are not enough parameters
        # available for the flag.
        if argv.size < arity
          raise ArgumentError.new
        end

        # Call the lambda with N items from argv,
        # where N is the lambda's arity.
        #flag.call(*argv.shift(arity).values)
        if arity == 0
          flag.call()
        elsif arity == 1
          flag.call(*argv.values_at(0))
        end
        
      else

        # Collect the items that don't correspond to
        # flags.
        args << item
      end
    end

    # TODO: should we replace the argv given with args?

    args
  end

test.cr

require "../src/clik"

# Simple example

opts = {} of Symbol => (String | Bool)
argv = ["-x"]

cli argv, {
  "-x" => ->{ opts[:x] = true } 
}

opts[:x].assert === true

# Another example

opts = {} of Symbol => (String | Bool)
argv = ["-w", "-f", "hello"]

cli argv, {
  "-w --whatever" => ->{ opts[:w] = true },
  "-f --file"     => ->(f){ opts[:f] = f },
  "-h --help"     => ->{ puts "help" }
}

opts[:w].assert == true
opts[:f].assert == "hello"

Error in ./test_click.cr:8: instantiating 'cli(Array(String), Hash(String, ( -> Bool)))'

cli argv, {
^~~

in /home/trans/Workspace/clik/src/clik.cr:52: wrong number of arguments for '( -> Void)#call' (1 for 0)

      flag.call(*argv.values_at(0))
           ^~~~