lib/json: infer type of simple JSON array at deserialization

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/json/serialization.nit b/lib/json/serialization.nit
index be9ee8c..19bea9e 100644 (file)
--- a/lib/json/serialization.nit
+++ b/lib/json/serialization.nit
@@ -301,10 +301,56 @@ class JsonDeserializer
                        return object
                end
 
+               # Simple JSON array without serialization metadata
                if object isa Array[nullable Object] then
-                       # special case, isa Array[nullable Serializable]
-                       var array = new Array[nullable Serializable]
-                       for e in object do array.add e.as(nullable Serializable)
+                       var array = new Array[nullable Object]
+                       var types = new HashSet[String]
+                       var has_nullable = false
+                       for e in object do
+                               var res = convert_object(e)
+                               array.add res
+
+                               if res != null then
+                                       types.add res.class_name
+                               else has_nullable = true
+                       end
+
+                       if types.length == 1 then
+                               var array_type = types.first
+
+                               var typed_array
+                               if array_type == "FlatString" then
+                                       if has_nullable then
+                                               typed_array = new Array[nullable FlatString]
+                                       else typed_array = new Array[FlatString]
+                               else if array_type == "Int" then
+                                       if has_nullable then
+                                               typed_array = new Array[nullable Int]
+                                       else typed_array = new Array[Int]
+                               else if array_type == "Float" then
+                                       if has_nullable then
+                                               typed_array = new Array[nullable Float]
+                                       else typed_array = new Array[Float]
+                               else
+                                       # TODO support all array types when we separate the constructor
+                                       # `from_deserializer` from the filling of the items.
+
+                                       if not has_nullable then
+                                               typed_array = new Array[Object]
+                                       else
+                                               # Unsupported array type, return as `Array[nullable Object]`
+                                               return array
+                                       end
+                               end
+
+                               assert typed_array isa Array[nullable Object]
+
+                               # Copy item to the new array
+                               for e in array do typed_array.add e
+                               return typed_array
+                       end
+
+                       # Uninferable type, return as `Array[nullable Object]`
                        return array
                end