Change some characters for printing (using UTF8)

demos/system-F-type/Print.ml

@@ -5,16 +5,19 @@ open F
 let arrow =
   string "->"
 
+let backslash =
+  string "λ"
+
 let doublebackslash =
-  string "\\\\"
+  string "Λ"
 
 let forall =
-  string "forall"
+  string "∀"
 
 let rec typ0 ty =
   match ty with
   | TyVar x ->
-      string x
+     string x
   | TyArrow _
   | TyProduct _
   | TyForall _ ->
@@ -66,7 +69,7 @@ and term1 t =
 and term2 t =
   match t with
   | TePair (t1, t2) ->
-      group (term1 t1 ^^ comma ^/^ term2 t2)
+      group (lparen ^^ term1 t1 ^^ comma ^/^ term2 t2 ^^ rparen)
   | _ ->
       term1 t
 
@@ -74,8 +77,8 @@ and term3 t =
   match t with
   | TeAbs (x, ty, t) ->
       block
-        (backslash ^^ string x ^^ spacecolon)
-        (break 1 ^^ typ ty)
+        (backslash ^^ string "(" ^^ string x ^^ spacecolon)
+        (break 1 ^^ typ ty ^^ string ")")
         (break 1 ^^ dot)
       ^/^
       term3 t