Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!decwrl!decvax!tektronix!tekcrl!tekgvs!toma
From: toma@tekgvs.GVS.TEK.COM (Tom Almy)
Newsgroups: comp.lang.misc
Subject: Re: Algol-style semicolons (was Re: What makes a language successful)
Keywords: semicolons, statements, end
Message-ID: <4396@tekgvs.GVS.TEK.COM>
Date: 19 Dec 88 18:16:01 GMT
References: <1126@etive.ed.ac.uk> <208100002@s.cs.uiuc.edu> <868@mcrware.UUCP>
Reply-To: toma@tekgvs.GVS.TEK.COM (Tom Almy)
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 23


The question in my mind is *not* "Is a semicolon a statement separator
or statment delimiter?" but *is* "Why do we need semicolons at all?".

Many years ago (about 20) I took a compiler writing class where we had
to write a compiler for an "Algol" like language.  A few weeks into the
project my partner and I noticed that the only thing our recursive descent
parser did with semicolons was to issue an error message if they were
absent!  So we altered the language spec to eliminate semicolons altogether!

In the same time frame, I was using BCPL (the predicessor of C).  BCPL would
assume a semicolon at the end of each line which could be successfully parsed
as a statment.  This eliminated virtually all the semicolons in every BCPL
program I wrote, yet the rule cost virtually nothing in parsing overhead.

I would contend that most, if not all, Algol-derived languages would work
just fine without semicolons!  The only problem being the way some languages
define  control structures require the existance of the semicolon as a null
statement.

Tom Almy
toma@tekgvs.tek.com
Standard Disclaimers Apply