From: Christoph <chr_news@...>
Date: 2002-09-27T01:35:16+09:00
Subject: Re: adding overload to ruby


"William Djaja Tjokroaminata" <billtj@z.glue.umd.edu> wrote in message
news:amv8tt$agp$1@grapevine.wam.umd.edu...
> Hi,
>
> I agree, but we have to be careful about the consequence of
> multi-dispatch.  In C++, this was accomplised using name mangling of the
> function; hopefully this needs not happen in Ruby.  But still, I think we
> need to deal with how to resolve ambiguities in multi-dispatch, which I
> think in C++, being a typed language, was complicated enough.

As far as I know there are essentially four possible ways to do
this

a). Some muddled C++ convention

b)  CLOS way - Use the lexicographic or similar order
     (for example a mixture of  path length + lexicographic order)
     on the multi-dispatch argument types  to determine the
     best (closest) match.  This is fairly unnatural imo.

c)  Determine if  a ``most specific '' specialization  on
     argument type (+ self type) exists. In case of ambiguities
     call  a method like ambiguous_method_call .
     (default action is to  raise an Exception) . This is Cecil's
     and Dylan's way I believe.

d)  (A combination of b & c).  Similar to c) but instead of
     raising an exception in the presence of ambiguities choose
     the  lexicographic largest (or largest in another
     good total order)  among  the ``most   specific type
      specializations.

e)  Maybe a combination of  c) & d)


Personally I  would probably go with d)


/Christoph