Re: LL(1) vs LALR(1) parsers

"steve (s.s.) simmons" <simmons@bnr.ca>
Wed, 15 Nov 1995 13:39:07 GMT

          From comp.compilers

Related articles
LL(1) vs LALR(1) parsers oaolsen@login.eunet.no (Odd Arild Olsen) (1995-11-04)
Re: LL(1) vs LALR(1) parsers krish@cs.purdue.edu (Saileshwar Krishnamurthy) (1995-11-09)
Re: LL(1) vs LALR(1) parsers sc@iaxp01.inf.uni-jena.de (Sebastian Schmidt) (1995-11-10)
Re: LL(1) vs LALR(1) parsers the_tick@access5.digex.net (1995-11-10)
Re: LL(1) vs LALR(1) parsers parrt@lonewolf.parr-research.com (1995-11-14)
Re: LL(1) vs LALR(1) parsers simmons@bnr.ca (steve (s.s.) simmons) (1995-11-15)
Re: LL(1) vs LALR(1) parsers parrt@parr-research.com (Terence John Parr) (1995-11-20)
Re: LL(1) vs LALR(1) parsers bill@amber.ssd.hcsc.com (1995-11-22)
Re: LL(1) vs LALR(1) parsers elliottc@logica.com (1995-11-24)
Re: LL(1) vs LALR(1) parsers jgj@ssd.hcsc.com (1995-11-28)
Re: LL(1) vs LALR(1) parsers will@ccs.neu.edu (1995-11-28)
Re: LL(1) vs LALR(1) parsers ddean@dynastar.cs.princeton.edu (1995-11-28)
[16 later articles]
| List of all articles for this month |

Newsgroups: comp.compilers
From: "steve (s.s.) simmons" <simmons@bnr.ca>
Keywords: parse, LALR, LL(1)
Organization: Bell-Northern Research Ltd.
References: 95-11-051
Date: Wed, 15 Nov 1995 13:39:07 GMT

> Why do compiler design text book authors only describe recursive parsers
> as a step stone on their way to bottom up parsers? I know that LALR allows
> for more complex grammars, but many languages can be described by LL(1)
> grammars. If LL(1) can yield faster, smaller and more understandable
> parsers with better error handling for many languages, why isn't this
> method more elaborated? (Holub, as an example, presents full grammar and
> compiler listings for a bottom-up C-compiler, not for top-down).


Intellectual bigotry!!!!!


That is, the automated parsers use a great deal of automata theory
which helps build on the computer science foundation. Recursive descent
parsers are a small matter of programming (SMOP). I do notice among
peers in industry that people are no longer snubbing the idea of writing
a recursive parser when it is appropiate.


Remember you don't take a compiler course to learn how to build a
compiler, surprise... Most people never write a compiler. You take
it for the following reasons:


- Improving your comp. sci. background to understand
automata theory with a very good application.
- Understanding what a compiler may do (or not do) for
your code.
- Learning about big system software, data structures, etc.


Thank you.


Steve Simmons
[I agree that few CS students will write a conventional compiler, but we all
end up having to decode some sort of input language in an application. -John]


--


Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.