Hello Adam, At a guess, ~ is ambiguous with the type equality syntax a ~ b. You'll probably have to add a new production for types (similar to atype) which are at the top level of a data constructor definition. I recently wrote some documentation on how to interpret Happy info files. There hasn't been a release yet but the docs are here: https://github.com/ezyang/happy/commit/daf84f5aa6f6453a118944f77393537f323d1... Cheers, Edward Excerpts from Adam Sandberg Eriksson's message of 2015-06-04 12:52:02 -0700:
Hello *,
I'm working on the -XStrict language extension[1] for this years Google summer of code. I've started with the smaller -XStrictData (as documented at the wiki) and have the internals mostly figured out.
However after adding relevant rules for '~' in the parser[2] I get an explosion of shift/reduce conflicts as well as 4 extra reduce/reduce conflicts, see [3] for the happy info (the states with 36 shift/reduce conflicts seem to be the problematic ones), I also fail to parse the test file [4] with the error
DsStrictData.hs:15:1: error: parse error (possibly incorrect indentation or mismatched brackets)
Can anyone offer some guidance on what the appropriate changes to the parser are to make these "lazyness" marks work?
Thanks, Adam
[1]: https://ghc.haskell.org/trac/ghc/wiki/StrictPragma [2]: https://github.com/adamse/ghc/blob/strict-pragma/compiler/parser/Parser.y#L1... [3]: https://gist.githubusercontent.com/adamse/8d6c54b6ae660fca8b97/raw/detailed-... [4]: https://github.com/adamse/ghc/blob/strict-pragma/testsuite/tests/deSugar/sho...