🚀 go-pugleaf

In article <8749@charon.cwi.nl> aeb@cwi.nl (Andries Brouwer) writes,
regarding problems turning YACC loose on natural languages:

>>(1) There are phenomena in natural language (including Swedish, I
>>believe) which are provably not context free.  Since the syntax used
>>in YACC is less than context-free (LALR(1), I believe), one of the
>>difficulties would be to change the syntax people used with the
>>translator.

>I do not think this is really a problem.

I see what you mean, i.e. that non context-free phenomena in natural
languages are few and far between.  But we're straying from the point.
The point is that you can't use YACC to handle natural languages.
YACC uses a LALR(1) table generation algorithm, and rejects all but
a relatively small subset of context free grammars.  In particular,
the parser cannot handle ambiguity in the tables.  You can remedy this
problem by using a parallel parser (a la Masaru Tomita), but only for
grammars with a fairly low level of ambiguity.  For high-ambiguity
situations, you're not doing any better than a chart parser.  So even
if you could extend YACC you would not be getting yourself very far
(unless you wanted to restrict yourself to a relatively small subset
of some natural language).

-- 

   -Richard L. Goerwitz              goer%midway@uchicago.bitnet
   goer@midway.uchicago.edu          rutgers!oddjob!ellis!goer