Hi,
On Tue, 1 Jul 2014, Simon Marlow wrote:
The s/r conflicts can also be a problem, depending on what you're trying to
parse. It's generally a good idea to get rid of them if you can, but at the
least you should understand why they exist (use happy --info) and document
them in Parser.y.pp.
OK I've uploaded the code to wip/T9023 and the happy --info report to
http://unsafePerform.IO/files/Parser.y.happy-info.gz
Loads of shift/reduce conflicts come from state 214. Looking at them, I
would have thought that the solution would be to parse pattern synonym
definitions like we parse data constructors as types: by parsing it as a
single pattern and then splitting it. A quick shortcut to this should be
to just disable the parsing rule for infix pattern synonyms; so I tried
that.
As expected, this cuts down on the number of shift/reduce conflicts in
that state considerably. The rest then seems to be coming from state 570:
patsyn_context -> forall . (rule 157)
patsyn_context -> forall . context '=>' (rule 158)
Unfortunately, I don't have a quick workaround for that one yet.
Thanks,
Gergo
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