Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!usc!snorkelwacker!husc6!spdcc!ima!esegue!compilers-sender
From: pardo@cs.washington.edu (David Keppel)
Newsgroups: comp.compilers
Subject: Re: Defining polymorphism vs. overloading
Keywords: polymorphism
Message-ID: <12978@june.cs.washington.edu>
Date: 7 Sep 90 17:01:04 GMT
References: <8133@amelia.nas.nasa.gov>
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: pardo@cs.washington.edu (David Keppel)
Organization: University of Washington, Computer Science, Seattle
Lines: 31
Approved: compilers@esegue.segue.boston.ma.us

>[Ongoing discussion of polymorphism & overloading.]

Given two uses (`T' denotes type):

	func (T) -> T
	func (T, T) -> T

is `func' overloaded, polymorphic, or neither?  Note that the
parameter types do not change but that the typ signature of the whole
call does change.  Does the O/P/N status depend on whether the
specification is

	func (T: x) -> T  { ... }
	func (T: x, T: y) -> T  { ... }

or

	func (T: x, optional T: y) -> T  { ... }

?

Ada allows default parameters, while some LISPs allow both defaults
and genuinely optional parmaeters.  Does that make a difference?

	;-D on  ( And is Eiffel's `feature' a documented bug? )  Pardo
-- 
		    pardo@cs.washington.edu
    {rutgers,cornell,ucsd,ubc-cs,tektronix}!uw-beaver!june!pardo
-- 
Send compilers articles to compilers@esegue.segue.boston.ma.us
{ima | spdcc | world}!esegue.  Meta-mail to compilers-request@esegue.