Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' has no declared type

glen herrmannsfeldt <gah@ugcs.caltech.edu>
Mon, 7 Nov 2011 05:08:00 +0000 (UTC)

          From comp.compilers

Related articles
bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' has alessandro.basili@cern.ch (Alessandro Basili) (2011-10-31)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' haberg-news@telia.com (Hans Aberg) (2011-10-31)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' alessandro.basili@cern.ch (Alessandro Basili) (2011-11-02)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' gneuner2@comcast.net (George Neuner) (2011-11-02)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' gneuner2@comcast.net (George Neuner) (2011-11-04)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' alessandro.basili@cern.ch (Alessandro Basili) (2011-11-06)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' gah@ugcs.caltech.edu (glen herrmannsfeldt) (2011-11-07)
Re: bison c-parse.y:1115.19-20: $$ for the midrule at $4 of `structsp' gneuner2@comcast.net (George Neuner) (2011-11-07)
| List of all articles for this month |

From: glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups: comp.compilers
Date: Mon, 7 Nov 2011 05:08:00 +0000 (UTC)
Organization: Aioe.org NNTP Server
References: 11-10-020 11-11-013 11-11-022 11-11-026
Keywords: bison, parse
Posted-Date: 07 Nov 2011 12:29:20 EST

Alessandro Basili <alessandro.basili@cern.ch> wrote:
(snip)
> That's another key point it worries me a lot. My goal is not to fix the
> compiler, but start using it to build my program for the aforementioned
> architecture. I would assume the shift/reduce conflicts is resulting
> from an incorrect description of the language, but if I can be able to
> understand what kind of construct of the language will trigger the
> conflict I can probably avoid to use it in my program.


Shift/reduce conflicts are not unusual, and not necessarily bad.


They often come from ambiguities in the language being parsed,
nested if-then-else being a favorite example. In many languages
with if-then-else, the else is defined to go with the nearest if,
but the syntax description doesn't know that. Specifying that
resolves the shift/reduce conflict.


Still, it might be worth trying to understand where the
conflicts come from to be sure that it is part of the
language definition.


As I understand it, though, reduce/reduce conflicts are not so
usual, and should be considered errors.


-- glen


Post a followup to this message

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