bug fixes in parsing etc; improved ImperC

2 files changed, 32 insertions, 22 deletions

diff --git a/examples/gfcc/ImperC.gf b/examples/gfcc/ImperC.gf
index a97688529..fd59e16d5 100644
--- a/examples/gfcc/ImperC.gf
+++ b/examples/gfcc/ImperC.gf
@@ -26,10 +26,10 @@ concrete ImperC of Imper = open ResImper in {
       } ;
 
     Decl  typ cont = continues (typ.s ++ cont.$0) cont ;
-    Assign _ x exp = continues (x.s ++ "=" ++ ex exp) ;
-    Return _ exp   = statement ("return" ++ ex exp) ;
-    While exp loop = continue  ("while" ++ paren (ex exp) ++ loop.s) ;
-    IfElse exp t f = continue  ("if" ++ paren (ex exp) ++ t.s ++ "else" ++ f.s) ;
+    Assign _ x exp = continues (x.s ++ "=" ++ exp.s) ;
+    Return _ exp   = statement ("return" ++ exp.s) ;
+    While exp loop = continue  ("while" ++ paren exp.s ++ loop.s) ;
+    IfElse exp t f = continue  ("if" ++ paren exp.s ++ t.s ++ "else" ++ f.s) ;
     Block stm      = continue  ("{" ++ stm.s ++ "}") ;
     End            = ss [] ;
  
@@ -50,6 +50,6 @@ concrete ImperC of Imper = open ResImper in {
     ConsTyp = cc2 ;
 
     NilExp = ss [] ;
-    OneExp _ e = ss (ex e) ;
-    ConsExp _ _ e es = ss (ex e ++ "," ++ es.s) ;
+    OneExp _ e = e ;
+    ConsExp _ _ e es = ss (e.s ++ "," ++ es.s) ;
 }
diff --git a/examples/gfcc/ResImper.gf b/examples/gfcc/ResImper.gf
index beea5f549..c392f078e 100644
--- a/examples/gfcc/ResImper.gf
+++ b/examples/gfcc/ResImper.gf
@@ -2,27 +2,37 @@ resource ResImper = open Predef in {
 
   -- precedence
 
+  param PAssoc = PN | PL | PR ;
+
   oper 
-    Prec     : PType = Predef.Ints 4 ;
-    PrecExp  : Type = {s : Prec => Str} ;
-    ex       : PrecExp -> Str = \exp -> exp.s ! 0 ;
-    constant : Str -> PrecExp = \c -> {s = \\_ => c} ;
-    infixN : Prec -> Str -> PrecExp -> PrecExp -> PrecExp = \p,f,x,y ->
-      {s = mkPrec (x.s ! (nextPrec ! p) ++ f ++ y.s ! (nextPrec ! p)) ! p} ;
-    infixL : Prec -> Str -> PrecExp -> PrecExp -> PrecExp = \p,f,x,y ->
-      {s = mkPrec (x.s ! p ++ f ++ y.s ! (nextPrec ! p)) ! p} ;
-
-    nextPrec : Prec => Prec = table {
+    Prec    : PType = Predef.Ints 4 ;
+    PrecExp : Type = {s : Str ; p : Prec ; a : PAssoc} ;
+
+    mkPrec : Prec -> PAssoc -> Str -> PrecExp = \p,a,f -> 
+      {s = f ; p = p ; a = a} ;
+
+    usePrec : PrecExp -> Prec -> Str = \x,p ->
+      case <<x.p,p> : Prec * Prec> of {
+        <3,4> | <2,3> | <2,4> => paren x.s ;
+        <1,1> | <1,0> | <0,0> => x.s ;
+        <1,_> | <0,_>         => paren x.s ;
+        _ => x.s
+        } ;
+
+    constant : Str -> PrecExp = mkPrec 4 PN ;
+
+    infixN : Prec -> Str -> (_,_ : PrecExp) -> PrecExp = \p,f,x,y ->
+      mkPrec p PN (usePrec x (nextPrec p) ++ f ++ usePrec y (nextPrec p)) ;
+    infixL : Prec -> Str -> (_,_ : PrecExp) -> PrecExp = \p,f,x,y ->
+      mkPrec p PL (usePrec x p ++ f ++ usePrec y (nextPrec p)) ;
+    infixR : Prec -> Str -> (_,_ : PrecExp) -> PrecExp = \p,f,x,y ->
+      mkPrec p PR (usePrec x (nextPrec p) ++ f ++ usePrec y p) ;
+
+    nextPrec : Prec -> Prec = \p -> case <p : Prec> of {
       4 => 4 ; 
       n => Predef.plus n 1
       } ;
 
-    mkPrec : Str -> Prec => Prec => Str = \str -> 
-      \\p,q => case Predef.lessInt p q of {
-        Predef.PTrue => paren str ;
-        _ => str
-        } ;
-
   -- string operations
 
     SS  : Type = {s : Str} ;