Fixes Model.to_json output

lib/model.ml

@@ -51,12 +51,16 @@ let to_string (model : t) : string =
   Format.asprintf "%a" (pp ~no_values:false) model
 
 let to_json (model : t) : Yojson.t =
-  let model :> Yojson.t list =
-    Hashtbl.fold
-      (fun s v acc ->
-        let s = Symbol.to_json s in
-        let v = `Assoc [ ("value", Value.to_json v) ] in
-        Yojson.Basic.Util.combine s v :: acc )
-      model []
+  let combine = Yojson.Basic.Util.combine in
+  let add_assignment sym value assignments =
+    let assignment =
+      match Symbol.to_json sym with
+      | `Assoc [ (name, props) ] ->
+        let value = `Assoc [ ("value", Value.to_json value) ] in
+        `Assoc [ (name, combine props value) ]
+      | _ -> failwith "Model: Symbol.to_json returned something impossible"
+    in
+    combine assignments assignment
   in
-  `Assoc [ ("model", `List model) ]
+  let model :> Yojson.t = Hashtbl.fold add_assignment model (`Assoc []) in
+  `Assoc [ ("model", model) ]

lib/symbol.ml

@@ -42,7 +42,6 @@ let rename (symbol : t) (name : string) : t = { symbol with name }
 let to_string ({ name; _ } : t) : string = name
 
 let to_json ({ name; ty } : t) : Yojson.Basic.t =
-  `Assoc
-    [ ("name", `String name); ("ty", `String (Format.asprintf "%a" Ty.pp ty)) ]
+  `Assoc [ (name, `Assoc [ ("ty", `String (Format.asprintf "%a" Ty.pp ty)) ]) ]
 
 let type_of ({ ty; _ } : t) : Ty.t = ty

test/unit/test_model.expected

@@ -1,8 +1,8 @@
 {
-  "model": [
-    { "name": "u", "ty": "str", "value": "abc" },
-    { "name": "z", "ty": "bool", "value": true },
-    { "name": "x", "ty": "int", "value": 1 },
-    { "name": "y", "ty": "real", "value": 2.0 }
-  ]
+  "model": {
+    "y": { "ty": "real", "value": 2.0 },
+    "x": { "ty": "int", "value": 1 },
+    "z": { "ty": "bool", "value": true },
+    "u": { "ty": "str", "value": "abc" }
+  }
 }