Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!yale!mintaka!spdcc!ima!esegue!compilers-sender
From: corbett@lupa.Eng.Sun.COM (Robert Corbett)
Newsgroups: comp.compilers
Subject: Re: Enumerated data types
Keywords: C, Pascal, design, Algol68
Message-ID: <141512@sun.Eng.Sun.COM>
Date: 29 Aug 90 02:50:24 GMT
References: <1990Aug23.134826.2865@forwiss.uni-passau.de> <3621@goanna.cs.rmit.oz.au> <141425@sun.Eng.Sun.COM>
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: corbett@lupa.Eng.Sun.COM (Robert Corbett)
Organization: Sun Microsystems, Mt. View, Ca.
Lines: 29
Approved: compilers@esegue.segue.boston.ma.us


In article <141425@sun.Eng.Sun.COM> grover@brahmand.Eng.Sun.COM (Vinod Grover) writes:
>In article <3621@goanna.cs.rmit.oz.au> ok@goanna.cs.rmit.OZ.AU (Richard A. O'Keefe) writes:
>>Algol 68 was the first language I met that allowed overloading, but from
>>the published discussions of the Algol 68 committee overloading was already
>>a well known idea then.  Anyone know where it first showed up?  ...

>I believe that Christopher Strachey used the term "ad hoc polymorphism" to
>refer to a breed of overloading. I *think* that was before Algol 68. 

>Vinod Grover
--- 

Many languages that supported overloading were designed before ALGOL 68.
MAD supported user-defined operator overloading.  The operators were
defined by giving assembly code for their implementation.  Aad van
Wijgaarden's paper "a Generalization of ALGOL" described a language that
supported overloading through user-defined rewriting rules.  The form of
overloading provided in ALGOL 68 pales by comparison.

During the early development of ALGOL 68, the ALGOL committee planned to
produce two languages, ALGOL X and ALGOL Y.  ALGOL X was to be a small
change to ALGOL 60 to fix its few remaining bugs.  ALGOL Y was to be the
long-term solution.  ALGOL X originally did not support extensibility.
Eventually, the ALGOL committee decided to retrofit retrofit some of the
advanced features from ALGOL Y to ALGOL X.

					Yours truly,
					Bob Corbett
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