Change syntax for qualified names in External Core

Two changes that make the ext-core code uglier but the parser easier:

- Prefix qualified names with "^" so that we can more easily
distinguish a qualified name:
   ^a:Foo.Bar.quux 
from an unqualified name:
   a

- z-encode package names ("ghc-prim" was the culprit.)

2 files changed, 11 insertions, 4 deletions

diff --git a/compiler/coreSyn/MkExternalCore.lhs b/compiler/coreSyn/MkExternalCore.lhs
index 1dc3b7e929..244144c22d 100644
--- a/compiler/coreSyn/MkExternalCore.lhs
+++ b/compiler/coreSyn/MkExternalCore.lhs
@@ -25,6 +25,7 @@ import Name
 import NameSet
 import UniqSet
 import Outputable
+import Encoding
 import ForeignCall
 import DynFlags
 import StaticFlags
@@ -219,13 +220,16 @@ make_var_id = make_id True
 -- *do* want to keep the package name (we don't want baseZCGHCziBase,
 -- because that would just be ugly.)
 -- SIGH.
+-- We encode the package name as well.
 make_mid :: Module -> C.Id
 -- Super ugly code, but I can't find anything else that does quite what I
 -- want (encodes the hierarchical module name without encoding the colon
 -- that separates the package name from it.)
-make_mid m = (packageIdString (modulePackageId m)) ++
-             ":" ++
-             showSDoc (pprCode CStyle (pprModuleName (moduleName m)))
+make_mid m = showSDoc $
+              (text $ zEncodeString $ packageIdString $ modulePackageId m)
+              <> text ":"
+              <> (pprEncoded $ pprModuleName $ moduleName m)
+     where pprEncoded = pprCode CStyle
                
 make_qid :: Bool -> Name -> C.Qual C.Id
 make_qid is_var n = (mname,make_id is_var n)
diff --git a/compiler/coreSyn/PprExternalCore.lhs b/compiler/coreSyn/PprExternalCore.lhs
index 22449df323..c58144c29c 100644
--- a/compiler/coreSyn/PprExternalCore.lhs
+++ b/compiler/coreSyn/PprExternalCore.lhs
@@ -80,7 +80,10 @@ pname id = text (zEncodeString id)
 
 pqname :: Qual Id -> Doc
 pqname ("",id) = pname id
-pqname (m,id)  = text m <> char '.' <> pname id
+-- We print out a special character before a qualified name so as to
+-- disambiguate unqualified names like "m" from qualified names like
+-- "m:Foo.Bar.y". This makes the ext-core parser easier.
+pqname (m,id)  = char '^' <> text m <> char '.' <> pname id
 
 ptbind, pattbind :: Tbind -> Doc
 ptbind (t,Klifted) = pname t