[Opencxx-users] Re: [opencxx] why no compiler-compiler to gen occ?

[Grzegorz J. <ja...@he...>]

On Sat, 26 Apr 2003, Shigeru Chiba wrote:

>
> Hi Larry,
>
>     Date: Fri, 25 Apr 2003 12:23:53 -0600
>     From: Larry Evans <jca...@pr...>
>     To: op...@cs...
>     Subject: why no compiler-compiler to gen occ?
>
>     > After downloading 2.6.1 and looking at the source files, I noticed
>     > there's no use of any kind of compiler-compiler such as antlr or
>     > yacc.  The source code in parse.h looks like it could be generated
>     > by antlr (since it's recursive decent); hence, I'm wondering why
>     > antlr or something like it wasn't used.

In "Design&Evolution" Stroustrup admits that using YACC for Cfront
implementation was a mistake and gave him lots of headaches.

Regards
Grzegorz


>
> The reason is simple.  Yacc, LALR(1), cannot parse C++ programs
> without awkward tricks of the lexical analyzer.  ANTLR was not very
> popular when OpenC++ was written in around 1995 (at least, I didn't
> know it.)  The final reason is that writing an LL(k) with-back-tracking
> parser by hand is easy.  At that time, I thought I should not have
> wasted time for finding some nice compiler-compiler but started
> writing a parser by hand.
>
> If I rewrite OpenC++ today, hmm.. I might use ANTLR.  I don't know.
>
> Chiba
>
>

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