a major refactoring in the C and the Haskell runtimes. Note incompatible change in the PGF format!!!

The following are the outcomes:

   - Predef.nonExist is fully supported by both the Haskell and the C runtimes

   - Predef.BIND is now an internal compiler defined token. For now
     it behaves just as usual for the Haskell runtime, i.e. it generates &+.
     However, the special treatment will let us to handle it properly in 
     the C runtime.

   - This required a major change in the PGF format since both 
     nonExist and BIND may appear inside 'pre' and this was not supported
     before.

1 files changed, 5 insertions, 3 deletions

diff --git a/src/runtime/haskell/PGF/Printer.hs b/src/runtime/haskell/PGF/Printer.hs
index c0529b116..9385e81c4 100644
--- a/src/runtime/haskell/PGF/Printer.hs
+++ b/src/runtime/haskell/PGF/Printer.hs
@@ -89,10 +89,12 @@ ppPrintName (id,name) =
 ppSymbol (SymCat d r) = char '<' <> int d <> comma <> int r <> char '>'
 ppSymbol (SymLit d r) = char '{' <> int d <> comma <> int r <> char '}'
 ppSymbol (SymVar d r) = char '<' <> int d <> comma <> char '$' <> int r <> char '>'
-ppSymbol (SymKS ts)   = ppStrs ts
-ppSymbol (SymKP ts alts) = text "pre" <+> braces (hsep (punctuate semi (ppStrs ts : map ppAlt alts)))
+ppSymbol (SymKS t)    = doubleQuotes (text t)
+ppSymbol SymNE        = text "nonExist"
+ppSymbol SymBIND      = text "BIND"
+ppSymbol (SymKP syms alts) = text "pre" <+> braces (hsep (punctuate semi (hsep (map ppSymbol syms) : map ppAlt alts)))
 
-ppAlt (Alt ts ps) = ppStrs ts <+> char '/' <+> hsep (map (doubleQuotes . text) ps)
+ppAlt (syms,ps) = hsep (map ppSymbol syms) <+> char '/' <+> hsep (map (doubleQuotes . text) ps)
 
 ppStrs ss = doubleQuotes (hsep (map text ss))