Change the syntax of Cons.

src/parser.mly

@@ -107,7 +107,7 @@ let expr :=
   | RETURN; lbl = expr_label; e = lhs; {
 		Return ((lbl,$startpos),e)
 	  }
-  | MATCH; lbl = expr_label; e1 = lhs; WITH; NIL; ARROW; e2 = expr; BAR; CONS; h = ID; r = ID; ARROW; e3 = expr; {
+  | MATCH; lbl = expr_label; e1 = lhs; WITH; NIL; ARROW; e2 = expr; BAR; CONS; LPAREN; h = ID; COMMA; r = ID; RPAREN; ARROW; e3 = expr; {
     Match ((lbl,$startpos),e1,e2,h,r,e3)
     }
 
@@ -143,7 +143,7 @@ let op :=
   | LPAREN; l = tuple_contents; RPAREN; <`Tuple>
   | ~ = array_expr; <`Read>
   | ~ = op; DOT; LENGTH; <`LengthOf>
-  | CONS; h = lhs; r = op; <`Cons>
+  | CONS; LPAREN; h = lhs; COMMA; r = op; RPAREN; <`Cons>
   | NIL; { `Nil }
 
 let tuple_rest :=

src/test/list/easy/alias-cons2.imp

@@ -1,17 +1,17 @@
 insert_second(l, x) {
   match l with
     Nil -> ()
-  | Cons h r -> {
+  | Cons (h, r) -> {
     let r2 = mkref *r in {
-      r := Cons x r2;
+      r := Cons (x, r2);
       alias(l.Cons.2 = r)
     }
   }
 }
 
 {
   let n = mkref Nil in
-  let l = Cons 0 n in {
+  let l = Cons (0, n) in {
     insert_second(l, 1);
     insert_second(l, 2);
   }

src/test/list/easy/cons.imp

@@ -1,6 +1,6 @@
 {
     let x = mkref Nil in
-    let y = mkref (Cons 1 x) in
-    let z = mkref (Cons 2 y) in
+    let y = mkref (Cons (1, x)) in
+    let z = mkref (Cons (2, y)) in
     ()
 }

src/test/list/easy/match-easy.imp

@@ -1,8 +1,8 @@
 {
     let x = mkref Nil in
-    let y = mkref (Cons 1 x) in
-    let z = Cons 2 y in
+    let y = mkref (Cons (1, x)) in
+    let z = Cons (2, y) in
     match z with
       Nil -> ()
-    | Cons h r -> ()
+    | Cons (h, r) -> ()
 }

src/test/list/easy/match.imp

@@ -1,7 +1,7 @@
 sum(l, s) {
     match l with
       Nil -> s
-    | Cons h r -> {
+    | Cons (h, r) -> {
         let s2 = s + h in
         let r2 = *r in {
             alias(l.Cons.2 = r);
@@ -12,9 +12,9 @@ sum(l, s) {
 
 {
     let x = mkref Nil in
-    let y = mkref (Cons 1 x) in
-    let z = mkref (Cons 2 y) in
-    let l = Cons 3 z in
+    let y = mkref (Cons (1, x)) in
+    let z = mkref (Cons (2, y)) in
+    let l = Cons (3, z) in
     let s = sum(l, 0) in
     assert(s = 6)
 }

src/test/list/hd.imp

@@ -3,20 +3,20 @@ mklist(n) {
         let h = _ in
         let m = n + -1 in
         let t = mkref mklist(m) in
-        Cons h t
+        Cons (h, t)
     }
 }
 
 hd(l) {
     match l with
       Nil -> fail
-    | Cons h t -> return h
+    | Cons (h, t) -> return h
 }
 
 {
     let n = ( _ : ~ > 0) in
     let l = mklist(n) in
     match l with
       Nil -> fail
-    | Cons h t -> assert(hd(l) = h)
+    | Cons (h, t) -> assert(hd(l) = h)
 }

src/test/list/length.imp

@@ -3,14 +3,14 @@ mklist(n) {
         let h = _ in
         let m = n + -1 in
         let t = mkref mklist(m) in
-        Cons h t
+        Cons (h, t)
     }
 }
 
 len(l) {
     match l with
       Nil -> return 0
-    | Cons h t -> {
+    | Cons (h, t) -> {
         let t_deref = *t in
         let n = 1 + len(t_deref) in {
             alias(t_deref = *t);

src/test/list/nth.imp

@@ -3,14 +3,14 @@ mklist(n) {
         let h = _ in
         let m = n + -1 in
         let t = mkref mklist(m) in
-        Cons h t
+        Cons (h, t)
     }
 }
 
 nth(l, n) {
     match l with
       Nil -> fail
-    | Cons h t -> {
+    | Cons (h, t) -> {
         let m = n + -1 in
         if n = 1 then h else nth(*t, m)
     }

src/test/list/tl.imp

@@ -3,7 +3,7 @@ mklist(n) {
         let h = _ in
         let m = n + -1 in
         let t = mkref mklist(m) in
-        Cons h t
+        Cons (h, t)
     }
 }
 
@@ -12,12 +12,12 @@ assert_eq(l1, l2) {
       Nil -> {
         match l2 with
           Nil -> ()
-        | Cons h2 t2 -> fail
+        | Cons (h2, t2) -> fail
       }
-    | Cons h1 t1 -> {
+    | Cons (h1, t1) -> {
         match l2 with
           Nil -> fail
-        | Cons h2 t2 -> {
+        | Cons (h2, t2) -> {
             assert(h1 = h2);
             let t1_deref = *t1 in
             let t2_deref = *t2 in {
@@ -34,13 +34,13 @@ assert_eq(l1, l2) {
 tl(l) {
     match l with
       Nil -> fail
-    | Cons h t -> return *t
+    | Cons (h, t) -> return *t
 }
 
 {
     let n = ( _ : ~ > 0) in
     let l = mklist(n) in
     match l with
       Nil -> fail
-    | Cons h t -> assert_eq(tl(l), *t)
+    | Cons (h, t) -> assert_eq(tl(l), *t)
 }