From: Dave Thomas <Dave@...>
Date: 2000-11-17T12:51:37+09:00
Subject: [ruby-talk:6410] Re: Dynamic languages need formal typing of public interfaces

Charles Hixson <charleshixsn@earthlink.net> writes:

> Andrew Hunt wrote:
> 
> > ...
> > Now, if you could match signatures based on some sort of semantic
> > description, then you'd have something.
> 
> Can we even define the semantics of a routine (other than by the source code)?
> This sounds like a DWIM language issue.  We'd need some sort of higher level
> meta-language.

Sure, at least in some cases. For example:

  def sqrt(n)
    pre: n >= 0
    post: result*result =~ n && result >= 0   (=~ means approx equal)

    code...
  end

That way you know the semantics of the routine by its post condition.


Dave