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From: johnl@esegue.segue.boston.ma.us (John R. Levine)
Newsgroups: comp.arch
Subject: Re: Algol, and language design
Message-ID: <1990Jul26.024449.1777@esegue.segue.boston.ma.us>
Date: 26 Jul 90 02:44:49 GMT
References: <25630@cs.yale.edu> <58091@lanl.gov>
Reply-To: johnl@esegue.segue.boston.ma.us (John R. Levine)
Followup-To: comp.arch,comp.compilers
Organization: Segue Software, Cambridge MA
Lines: 25

In article <58091@lanl.gov> jlg@lanl.gov (Jim Giles) writes:
>Well yes, ALGOL _has_ had an enormous _negative_ impact on language
>design (that still continues today).  Features like 'call-by-name' are
>now recognized as bad by nearly everyone.

Alan Perlis, who was on the Algol committee, once told me that when they
defined call-by-name, they thought they were defining call-by-reference
more elegantly.  When Jensen invented his now-notorious device and they
realized what they had created, they were as surprised as anyone.  Oops.

>In fact, only two features, that I can find, are original to ALGOL and
>have a continuing positive influence on language design: if-then-else
>and while().

How about nested scopes and recursion?  I find them handy from time to time.

I'd also be interested to hear what about compound statements (by which I
presume you mean BEGIN ... END blocks) is bad, and whether the Algol 68
approach in which every control structure has its own closing word, obviating
begin and end, is any better.

-- 
John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 864 9650
johnl@esegue.segue.boston.ma.us, {ima|lotus|spdcc}!esegue!johnl
Marlon Brando and Doris Day were born on the same day.