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| author | simonpj@microsoft.com <unknown> | 2009-07-02 09:46:57 +0000 |
|---|---|---|
| committer | simonpj@microsoft.com <unknown> | 2009-07-02 09:46:57 +0000 |
| commit | 432b9c9322181a3644083e3c19b7e240d90659e7 (patch) | |
| tree | affb919c8731145d0353f2ec828f11304ff40ca0 /compiler/deSugar | |
| parent | 25cead299c5857b9142a82c917080a654be44b83 (diff) | |
| download | haskell-432b9c9322181a3644083e3c19b7e240d90659e7.tar.gz | |
New syntax for GADT-style record declarations, and associated refactoring
The main purpose of this patch is to fix Trac #3306, by fleshing out the
syntax for GADT-style record declraations so that you have a context in
the type. The new form is
data T a where
MkT :: forall a. Eq a => { x,y :: !a } -> T a
See discussion on the Trac ticket.
The old form is still allowed, but give a deprecation warning.
When we remove the old form we'll also get rid of the one reduce/reduce
error in the grammar. Hurrah!
While I was at it, I failed as usual to resist the temptation to do lots of
refactoring. The parsing of data/type declarations is now much simpler and
more uniform. Less code, less chance of errors, and more functionality.
Took longer than I planned, though.
ConDecl has record syntax, but it was not being used consistently, so I
pushed that through the compiler.
Diffstat (limited to 'compiler/deSugar')
| -rw-r--r-- | compiler/deSugar/DsMeta.hs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/compiler/deSugar/DsMeta.hs b/compiler/deSugar/DsMeta.hs index 2de2cae080..3518aaf87f 100644 --- a/compiler/deSugar/DsMeta.hs +++ b/compiler/deSugar/DsMeta.hs @@ -372,14 +372,14 @@ ds_msg = ptext (sLit "Cannot desugar this Template Haskell declaration:") ------------------------------------------------------- repC :: LConDecl Name -> DsM (Core TH.ConQ) -repC (L _ (ConDecl con _ [] (L _ []) details ResTyH98 _)) +repC (L _ (ConDecl { con_name = con, con_qvars = [], con_cxt = L _ [] + , con_details = details, con_res = ResTyH98 })) = do { con1 <- lookupLOcc con -- See note [Binders and occurrences] ; repConstr con1 details } -repC (L loc (ConDecl con expl tvs (L cloc ctxt) details ResTyH98 doc)) +repC (L loc con_decl@(ConDecl { con_qvars = tvs, con_cxt = L cloc ctxt, con_res = ResTyH98 })) = addTyVarBinds tvs $ \bndrs -> - do { c' <- repC (L loc (ConDecl con expl [] (L cloc []) details - ResTyH98 doc)) + do { c' <- repC (L loc (con_decl { con_qvars = [], con_cxt = L cloc [] })) ; ctxt' <- repContext ctxt ; bndrs' <- coreList tyVarBndrTyConName bndrs ; rep2 forallCName [unC bndrs', unC ctxt', unC c'] |