CLIs with subcommands that don't suck.

seali.rb

# NOTE: This is a WIP, please pardon our dust.
#
# Example:
#
# git --namespace=foobar clone https://github.com/nixpulvis/seali
# #<Git @args=[], @flags={namespace: "foobar"}, @sub=#<Clone @args=["https://github.com/nixpulvis/seali"], @flags=[], @sub=nil>>

class Seali
  class << self
    attr_accessor :subs
    attr_accessor :cmd_func
    attr_accessor :flg_funcs

    def cmd(&block)
      self.cmd_func = block
    end

    def flg(short, long = nil, argument = nil, &block)
      self.flg_funcs[name] = block
    end

    def sub(name, cli)
      self.subs[name.to_s] = cli
    end

    def inherited(subclass)
      subclass.cmd_func = Proc.new { p "???" }
      subclass.flg_funcs = {}
      subclass.subs = {}
    end
  end

  def initialize(args)
    @args = []
    @flags = {}
    parse(args[0], args[1..-1])
  end

  def parse(first, rest)
    return if first.nil?

    if self.class.subs[first]
      @sub = self.class.subs[first].new(rest)
      return
    end

    if first.start_with?('-')
      @flags[first] = nil  # TODO: Parse the value if there is one. All flags with values MUST use an `=`.
    else
      @args << first
    end

    parse(rest[0], rest[1..-1])
  end

  def run(&block)
    self.class.flg_funcs.each do |name, func|
      func.call
    end

    if @sub
      @sub.run
    else
      self.instance_eval(&self.class.cmd_func)
    end
  end
end