cnd.rb

cnd.rb

alias λ proc
alias _l proc

class Object
  def cnd(t:λ{},f:λ{})
    t[]
  end
end

class NilClass
  def cnd(t:λ{},f:λ{})
    f[]
  end
end

class FalseClass
  def cnd(t:λ{},f:λ{})
    f[]
  end
end

if $0 == __FILE__
  require 'minitest/autorun'

  Class.new(Minitest::Test) do
    def test_cnd
      1.nonzero?.cnd t: λ{ assert "it's nonzero" }, f: λ{ fail "it's zero" }
    end

    def test_omit
      1.nonzero?.cnd f: _l{ fail "it's zero" }
    end
  end
end