RichTokenStream support

[ghc-hetmet.git] / compiler / parser / Parser.y.pp

diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index 86ce98c..b51edf2 100644 (file)
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -495,13 +495,17 @@ importdecls :: { [LImportDecl RdrName] }
        | {- empty -}                           { [] }
 
 importdecl :: { LImportDecl RdrName }
-       : 'import' maybe_src optqualified modid maybeas maybeimpspec 
-               { L (comb4 $1 $4 $5 $6) (ImportDecl $4 $2 $3 (unLoc $5) (unLoc $6)) }
+       : 'import' maybe_src optqualified maybe_pkg modid maybeas maybeimpspec 
+               { L (comb4 $1 $5 $6 $7) (ImportDecl $5 $4 $2 $3 (unLoc $6) (unLoc $7)) }
 
 maybe_src :: { IsBootInterface }
        : '{-# SOURCE' '#-}'                    { True }
        | {- empty -}                           { False }
 
+maybe_pkg :: { Maybe FastString }
+        : STRING                                { Just (getSTRING $1) }
+        | {- empty -}                           { Nothing }
+
 optqualified :: { Bool }
        : 'qualified'                           { True  }
        | {- empty -}                           { False }
@@ -1429,16 +1433,27 @@ cvtopdecls0 :: { [LHsDecl RdrName] }
        : {- empty -}           { [] }
        | cvtopdecls            { $1 }
 
--- tuple expressions: things that can appear unparenthesized as long as they're
+-- "texp" is short for tuple expressions: 
+-- things that can appear unparenthesized as long as they're
 -- inside parens or delimitted by commas
 texp :: { LHsExpr RdrName }
        : exp                           { $1 }
-       -- Technically, this should only be used for bang patterns,
-       -- but we can be a little more liberal here and avoid parens
-       -- inside tuples
-       | infixexp qop  { LL $ SectionL $1 $2 }
+
+       -- Note [Parsing sections]
+       -- ~~~~~~~~~~~~~~~~~~~~~~~
+       -- We include left and right sections here, which isn't
+       -- technically right according to Haskell 98.  For example
+       --      (3 +, True) isn't legal
+       -- However, we want to parse bang patterns like
+       --      (!x, !y)
+       -- and it's convenient to do so here as a section
+        -- Then when converting expr to pattern we unravel it again
+       -- Meanwhile, the renamer checks that real sections appear
+       -- inside parens.
+        | infixexp qop         { LL $ SectionL $1 $2 }
        | qopm infixexp       { LL $ SectionR $1 $2 }
-       -- view patterns get parenthesized above
+
+       -- View patterns get parenthesized above
        | exp '->' exp   { LL $ EViewPat $1 $3 }
 
 texps :: { [LHsExpr RdrName] }