Re: syntactic completion

[Vincent Zweije]

On Sat, Jul 31, 2004 at 08:33:23PM +0200, Hans Aberg wrote:

||  So you merely wanted to point out that the
||  $default-compaction technique as such is not a part of
||  LALR(1)-compaction. (I did not look too carefully at this
||  particular point; just assumed it was a part of LALR(1).)

Yes.

||  We agree though, both (as you say below), that the LR(1)
||  states are the ones with the correct 1-lookahead sets for a
||  completion, and only compaction techniques that are able to
||  restore that set will give formally correct results. One
||  may get an acceptable results also with other algorithms,
||  such as LALR(1) -- but be prepared if the enduser complains
||  that certain error tokens appear in the completion lists!
||
||  In general, though, there seems to be a growing need for
||  more exact error recovery, which suggests Bison would
||  benefit to in the future support LR(1). This completions
||  request is just one in that batch.

Given that LALR grammars will do the job for most of the parsing
tasks and that it produces smaller tables, its use is not going
to go away.

However with the coming of larger hardware, LR parsing becomes
feasible, and it has certain advantages over LALR, such as more
exact error reporting and, it turns out now, completion.

What I mean to say is, yes, LR has its useful sides too, but the
compactness of LALR will still make it the preferred technique
for the majority of parsing applications.  Just don't try to
make bison an LR-only parser.  (As if I thought you would.)

Ciao.                                                   Vincent.
--
Answer: no.
Question: should I reply before the quote?