Implement JSON array concatenation

Issue: eng/gpr/gpr-issues#739

Author: Jicquel

core/src/gnatcoll-json.adb

@@ -953,6 +953,13 @@ package body GNATCOLL.JSON is
       Arr.Vals.Append (Val);
    end Append;
 
+   procedure Append (Arr : in out JSON_Array; Val : JSON_Array) is
+   begin
+      for Value of Val.Vals loop
+         Arr.Vals.Append (Value);
+      end loop;
+   end Append;
+
    -------------
    -- Prepend --
    -------------
@@ -962,6 +969,13 @@ package body GNATCOLL.JSON is
       Arr.Vals.Prepend (Val);
    end Prepend;
 
+   procedure Prepend (Arr : in out JSON_Array; Val : JSON_Array) is
+   begin
+      for Value of reverse Val.Vals loop
+         Arr.Vals.Prepend (Value);
+      end loop;
+   end Prepend;
+
    ---------
    -- "&" --
    ---------

core/src/gnatcoll-json.ads

@@ -219,9 +219,15 @@ package GNATCOLL.JSON is
    procedure Append (Arr : in out JSON_Array; Val : JSON_Value);
    --  Append Val as a new element at the end of the Arr array
 
+   procedure Append (Arr : in out JSON_Array; Val : JSON_Array);
+   --  Append all values of Val at the end of the Arr array
+
    procedure Prepend (Arr : in out JSON_Array; Val : JSON_Value);
    --  Insert Val as the first element of the Arr array
 
+   procedure Prepend (Arr : in out JSON_Array; Val : JSON_Array);
+   --  Insert all values of Val at the beginning of the Arr array
+
    procedure Clear (Arr : in out JSON_Array);
    --  Remove all elements in Arr
 

testsuite/core/tests/json/api/test.adb

@@ -82,7 +82,11 @@ function Test return Integer is
 
    Int_0       : JSON_Value := Create (Integer'(0));
    Int_1       : constant JSON_Value := Create (Integer'(1));
+   Int_2       : constant JSON_Value := Create (Integer'(2));
+   Int_3       : constant JSON_Value := Create (Integer'(3));
+
    Hello_World : constant JSON_Value := Create ("Hello world!");
+   Hi_World    : constant JSON_Value := Create ("Hi world!");
 
    Float_0 : constant JSON_Value := Create (Float'(0.0));
    Float_1 : constant JSON_Value := Create (Float'(1.0));
@@ -99,6 +103,7 @@ begin
 
    declare
       Arr   : JSON_Array := Int_0 & Int_1 & Hello_World;
+      Arr2  : constant JSON_Array := Int_2 & Int_3 & Hi_World;
       Empty : constant JSON_Array := Empty_Array;
    begin
       --  Inspect an empty array
@@ -143,6 +148,26 @@ begin
       Clear (Arr);
       A.Assert (Length (Arr) = 0);
 
+      Arr := Hello_World & Int_0 & Int_1;
+      Append (Arr, Arr2);
+      A.Assert (Length (Arr) = 6);
+      A.Assert (Get (Arr, 1) = Hello_World);
+      A.Assert (Get (Arr, 2) = Int_0);
+      A.Assert (Get (Arr, 3) = Int_1);
+      A.Assert (Get (Arr, 4) = Int_2);
+      A.Assert (Get (Arr, 5) = Int_3);
+      A.Assert (Get (Arr, 6) = Hi_World);
+
+      Arr := Hello_World & Int_0 & Int_1;
+      Prepend (Arr, Arr2);
+      A.Assert (Length (Arr) = 6);
+      A.Assert (Get (Arr, 1) = Int_2);
+      A.Assert (Get (Arr, 2) = Int_3);
+      A.Assert (Get (Arr, 3) = Hi_World);
+      A.Assert (Get (Arr, 4) = Hello_World);
+      A.Assert (Get (Arr, 5) = Int_0);
+      A.Assert (Get (Arr, 6) = Int_1);
+
       Arr := Hello_World & Int_0 & Int_1 & Int_0;
       Sort (Arr, Less'Access);
       Check_Image (Create (Arr), "[0,0,1,""Hello world!""]");