From: "T. Onoma" <transami@...>
Date: 2003-11-21T05:52:57+09:00
Subject: Partial Euphoric Type Checking

Greetings all Type Checkers!

I have implemented a version of euphoria's type system in Ruby.

  # the good stuff

  module Kernel
    def typechecking(x=nil)
      return $_tc if x == nil
      $_tc = x ? true : false
    end
  end

  class Module
    def type(tname, &check)
      define_method(tname) do |*v|
        if $_tc
          unless v.all? { |y| check.call(y) }
            raise TypeError
          end
        end
        return *v
      end
    end
  end

  # demonstrate how it feels

  class TypeTest
    type :big4 do |x|
      x > 4
    end
    def ameth(x)
      # -- type checking --
      big4 x  
      # -- rest of code --
      puts x
    end
  end

  typechecking true  # turn type checking on
  t = TypeTest.new
  t.ameth(5)  # => 5
  t.ameth(2)  # => TypeError

Now if you can just get matz to add a little sytax sugar for type and inline parameter methods:

  class TypeTest
    type big4(x)
      x > 4
    end
    def ameth(big4 x)
      puts x
    end
  end

would that quell the need?

-t0