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

[Shigeru C. <ch...@is...>]

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.

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