Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!otter!esh
From: esh@otter.hple.hp.com (Sean Hayes)
Newsgroups: comp.lang.misc
Subject: Re: Block Closure (was Re: FOR loops)
Message-ID: <2400015@otter.hple.hp.com>
Date: 21 Apr 88 14:59:11 GMT
References: <918@rlgvax.UUCP>
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Lines: 19


>The problem with the idea mentioned in other postings about using indentation
>to represent the control structure is that it does not have a clean formalism
>to describe the parser.  Many languages that are in use can be described with
>LR derived parsing specifications and thus the syntax of the language can
>be dealt with formally.   I don't think that using whitespace as part of the 
>syntax of the language will be easy to parse.   Problems include: handling
>of multi line expressions and defining default tab stops.

Although it is exteremely convenient to be able to specify a language formally,
Surely context free grammars aren't the last word in formal description methods.

I think tools like yacc and lex may have done a great deal to inhibit 
language development.  They certainly shouldn't (in my lowly opinion)
be used as an excuse to remove language features on the 'hard to parse' argument.
On the other hand, whats hard for a parser is often hard for a programmer too.

 _________________________________________________________________________
 |Sean Hayes,          Hewlett Packard Laboratories,      Bristol,  England|
 |net: esh@hplb.uucp   esh%shayes@hplabs.HP.COM       ..!mcvax!ukc!hplb!esh|