use intermediary tuple access to get key and value for maps. add tests.

src/passes/2-simplify/pascaligo.ml

@@ -138,16 +138,6 @@ module Errors = struct
     ] in
     error ~data title message
 
-  let unsupported_for_collect_map for_col =
-    let title () = "for loop over map" in
-    let message () =
-      Format.asprintf "for loops over map are not supported yet" in
-    let data = [
-      ("loop_loc",
-       fun () -> Format.asprintf "%a" Location.pp_lift @@ for_col.Region.region)
-    ] in
-    error ~data title message
-
   (* Logging *)
 
   let simplifying_instruction t =
@@ -1071,7 +1061,6 @@ and simpl_for_int : Raw.for_int -> (_ -> expression result) result = fun fi ->
 
 **)
 and simpl_for_collect : Raw.for_collect -> (_ -> expression result) result = fun fc ->
-  match fc.collection with | Map _ -> fail @@ unsupported_for_collect_map fc.block | _ ->
   (* STEP 1 *)
   let%bind for_body = simpl_block fc.block.value in
   let%bind for_body = for_body None in
@@ -1136,10 +1125,16 @@ and simpl_for_collect : Raw.for_collect -> (_ -> expression result) result = fun
     let ( arg_access: Types.access_path -> expression ) = e_accessor (e_variable "arguments") in
     ( match fc.collection with 
       | Map _ ->
-        let acc          = arg_access [Access_tuple 0 ; Access_tuple 0] in
+        (* let acc          = arg_access [Access_tuple 0 ; Access_tuple 0] in
         let collec_elt_v = arg_access [Access_tuple 1 ; Access_tuple 0] in
-        let collec_elt_k = arg_access [Access_tuple 1 ; Access_tuple 1] in
+        let collec_elt_k = arg_access [Access_tuple 1 ; Access_tuple 1] in *)
+        (* The above should work, but not yet (see LIGO-131) *)
+        let temp_kv      = arg_access [Access_tuple 1] in
+        let acc          = arg_access [Access_tuple 0] in
+        let collec_elt_v = e_accessor (e_variable "#COMPILER#temp_kv") [Access_tuple 0] in
+        let collec_elt_k = e_accessor (e_variable "#COMPILER#temp_kv") [Access_tuple 1] in
         e_let_in ("#COMPILER#acc", None) acc @@
+        e_let_in ("#COMPILER#temp_kv", None) temp_kv @@
         e_let_in ("#COMPILER#collec_elt_k", None) collec_elt_v @@
         e_let_in ("#COMPILER#collec_elt_v", None) collec_elt_k (for_body)
       | _ ->

src/test/contracts/loop.ligo

@@ -116,16 +116,25 @@ function for_collection_empty (var nee : unit) : int is block {
   end
 } with acc
 
-// function for_collection_map (var nee : unit) : (int * string) is block {
-//   var acc : int := 0 ;
-//   var st : string := "" ;
-//   var mymap : map(string,int) := map "one" -> 1 ; "two" -> 2 ; "three" -> 3 end ;
-//   for k -> v : (string * int) in map mymap
-//   begin
-//     acc := acc + v ;
-//     st := k^st ;
-//   end
-// } with (acc, st)
+function for_collection_map_kv (var nee : unit) : (int * string) is block {
+  var acc : int := 0 ;
+  var st : string := "" ;
+  var mymap : map(string,int) := map "1" -> 1 ; "2" -> 2 ; "3" -> 3 end ;
+  for k -> v : (string * int) in map mymap
+  begin
+    acc := acc + v ;
+    st := st^k ;
+  end
+} with (acc, st)
+
+function for_collection_map_k (var nee : unit) : string is block {
+  var st : string := "" ;
+  var mymap : map(string,int) := map "1" -> 1 ; "2" -> 2 ; "3" -> 3 end ;
+  for k : string in map mymap
+  begin
+    st := st^k ;
+  end
+} with st
 
 function dummy (const n : nat) : nat is block {
   while (False) block { skip }

src/test/integration_tests.ml

@@ -667,6 +667,12 @@ let loop () : unit result =
   let%bind () = 
     let expected = e_pair (e_int 6) (e_string "totototo") in
     expect_eq program "for_collection_set" input expected in
+  let%bind () = 
+    let expected = e_pair (e_int 6) (e_string "123") in
+    expect_eq program "for_collection_map_kv" input expected in
+  let%bind () = 
+    let expected = (e_string "123") in
+    expect_eq program "for_collection_map_k" input expected in
   let%bind () = 
     let expected = (e_int 0) in
     expect_eq program "for_collection_empty" input expected in