List; add indexOf(value)

doc/site/modules/core/list.markdown

@@ -32,6 +32,16 @@ Removes all elements from the list.
 
 The number of elements in the list.
 
+### **indexOf(value)**
+
+Returns the index of `value` in the list, if found. If not found, returns -1.
+
+<pre class="snippet">
+var list = [0, 1, 2, 3, 4]
+System.print(list.indexOf(3)) //> 3
+System.print(list.indexOf(20)) //> -1
+</pre>
+
 ### **insert**(index, item)
 
 Inserts the `item` at `index` in the list.

src/vm/wren_core.c

@@ -394,6 +394,12 @@ DEF_PRIMITIVE(list_removeAt)
   RETURN_VAL(wrenListRemoveAt(vm, list, index));
 }
 
+DEF_PRIMITIVE(list_indexOf)
+{
+  ObjList* list = AS_LIST(args[0]);
+  RETURN_NUM(wrenListIndexOf(vm, list, args[1]));
+}
+
 DEF_PRIMITIVE(list_subscript)
 {
   ObjList* list = AS_LIST(args[0]);
@@ -1360,6 +1366,7 @@ void wrenInitializeCore(WrenVM* vm)
   PRIMITIVE(vm->listClass, "iterate(_)", list_iterate);
   PRIMITIVE(vm->listClass, "iteratorValue(_)", list_iteratorValue);
   PRIMITIVE(vm->listClass, "removeAt(_)", list_removeAt);
+  PRIMITIVE(vm->listClass, "indexOf(_)", list_indexOf);
 
   vm->mapClass = AS_CLASS(wrenFindVariable(vm, coreModule, "Map"));
   PRIMITIVE(vm->mapClass->obj.classObj, "new()", map_new);

src/vm/wren_value.c

@@ -319,6 +319,19 @@ void wrenListInsert(WrenVM* vm, ObjList* list, Value value, uint32_t index)
   list->elements.data[index] = value;
 }
 
+int wrenListIndexOf(WrenVM* vm, ObjList* list, Value value)
+{
+  int count = list->elements.count;
+  for (int i = 0; i < count; i++)
+  {
+    Value item = list->elements.data[i];
+    if(wrenValuesEqual(item, value)) {
+      return i;
+    }
+  }
+  return -1;
+}
+
 Value wrenListRemoveAt(WrenVM* vm, ObjList* list, uint32_t index)
 {
   Value removed = list->elements.data[index];

src/vm/wren_value.h

@@ -680,6 +680,9 @@ void wrenListInsert(WrenVM* vm, ObjList* list, Value value, uint32_t index);
 // Removes and returns the item at [index] from [list].
 Value wrenListRemoveAt(WrenVM* vm, ObjList* list, uint32_t index);
 
+// Searches for [value] in [list], returns the index or -1 if not found.
+int wrenListIndexOf(WrenVM* vm, ObjList* list, Value value);
+
 // Creates a new empty map.
 ObjMap* wrenNewMap(WrenVM* vm);
 

test/core/list/index_of.wren

@@ -0,0 +1,8 @@
+
+var list = [0, 1, 2, 3, 4]
+System.print(list.indexOf(4))   // expect: 4
+System.print(list.indexOf(2))   // expect: 2
+System.print(list.indexOf(3))   // expect: 3
+System.print(list.indexOf(0))   // expect: 0
+System.print(list.indexOf(100)) // expect: -1
+System.print(list.indexOf(-1))  // expect: -1