Implement InstanceSigs

README.md

@@ -71,6 +71,7 @@ Differences:
    * ImportShadowing
    * ImportQualifiedPost
    * IncoherentInstances
+   * InstanceSigs
    * KindSignatures
    * LambdaCase
    * MonoLocalBinds

src/MicroHs/Parse.hs

@@ -817,7 +817,7 @@ pClsBind =
 pInstBind :: P EBind
 pInstBind =
       uncurry Fcn <$> pEqns
--- no InstanceSig yet  <|< Sign        <$> (pLIdentSym <* dcolon) <*> pType
+  <|< Sign        <$> ((esepBy1 pLIdentSym (pSpec ',')) <* dcolon) <*> pType
 
 -------------
 

src/MicroHs/TypeCheck.hs

@@ -1309,13 +1309,16 @@ expandInst dinst@(Instance act ib) = do
       InstanceBody bs -> do
         -- XXX this ignores type signatures and other bindings
         -- XXX should tack on signatures with ESign
-        let clsMdl = qualOf qiCls                   -- get class's module name
-            ies = [(i, ELam loc qs) | Fcn i qs <- bs]
+        let signs = [ (i, t) | Sign is t <- bs, i <- is ]
+            addSign i e = maybe e (ESign e) $ lookup i signs
+            clsMdl = qualOf qiCls                   -- get class's module name
+            ies = [(i, addSign i $ ELam loc qs) | Fcn i qs <- bs]
             meth i = fromMaybe (ELam loc $ simpleEqn $ EVar $ setSLocIdent loc $ mkDefaultMethodId $ qualIdent clsMdl i) $ lookup i ies
             meths = map meth mis
             sups = map (const (EVar $ mkIdentSLoc loc dictPrefixDollar)) supers
             args = sups ++ meths
             instBind (Fcn i _) = i `elem` mis
+            instBind (Sign is _) = all (`elem` mis) is
             instBind _ = False
         case filter (not . instBind) bs of
           [] -> return ()