Added 'instanceof' binary operation to the API (#2751)

Added 'JERRY_BIN_OP_INSTANCEOF' to 'jerry_binary_operation_t' and
'jerry_binary_operation'. Added unit tests for this new operation
and updated the documentations.

JerryScript-DCO-1.0-Signed-off-by: László Langó llango.u-szeged@partner.samsung.com

docs/02.API-REFERENCE.md

@@ -286,6 +286,7 @@ Enum that contains the supported binary operation types
  - JERRY_BIN_OP_LESS_EQUAL - less or equal relation (<=)
  - JERRY_BIN_OP_GREATER - greater relation (>)
  - JERRY_BIN_OP_GREATER_EQUAL - greater or equal relation (>=)
+ - JERRY_BIN_OP_INSTANCEOF - instanceof operation
 
 
 ## jerry_property_descriptor_t
@@ -1092,6 +1093,7 @@ jerry_get_global_object (void);
 - [jerry_release_value](#jerry_release_value)
 - [jerry_define_own_property](#jerry_define_own_property)
 
+
 # Checker functions
 
 Functions to check the type of an API value ([jerry_value_t](#jerry_value_t)).
@@ -1741,7 +1743,7 @@ jerry_binary_operation (jerry_binary_operation_t op,
   - error, if argument has an error flag or operation is unsuccessful or unsupported
   - true/false, the result of the binary operation on the given operands otherwise
 
-**Example**
+**Example - JERRY_BIN_OP_EQUAL**
 
 ```c
 {
@@ -1772,6 +1774,59 @@ jerry_binary_operation (jerry_binary_operation_t op,
 }
 ```
 
+**Example - JERRY_BIN_OP_INSTANCEOF**
+
+[doctest]: # ()
+
+```c
+#include "jerryscript.h"
+
+static jerry_value_t
+my_constructor (const jerry_value_t func_val,
+                const jerry_value_t this_val,
+                const jerry_value_t argv[],
+                const jerry_length_t argc)
+{
+  return jerry_create_undefined ();
+}
+
+int
+main (void)
+{
+  jerry_init (JERRY_INIT_EMPTY);
+
+  jerry_value_t base_obj = jerry_create_object ();
+  jerry_value_t constructor = jerry_create_external_function (my_constructor);
+
+  /* External functions does not have a prototype by default, so we need to create one */
+  jerry_value_t prototype_str = jerry_create_string ((const jerry_char_t *) ("prototype"));
+  jerry_release_value (jerry_set_property (constructor, prototype_str, base_obj));
+  jerry_release_value (prototype_str);
+
+  /* Construct the instance. */
+  jerry_value_t instance_val = jerry_construct_object (constructor, NULL, 0);
+
+  /* Call the API function of 'instanceof'. */
+  jerry_value_t is_instance = jerry_binary_operation (JERRY_BIN_OP_INSTANCEOF,
+                                                      instance_val,
+                                                      constructor);
+  if (!jerry_value_is_error (is_instance)
+      && jerry_get_boolean_value (is_instance) == true)
+  {
+    /* ... */
+  }
+
+  /* Free all of the jerry values and cleanup the engine. */
+  jerry_release_value (base_obj);
+  jerry_release_value (constructor);
+  jerry_release_value (instance_val);
+  jerry_release_value (is_instance);
+
+  jerry_cleanup ();
+  return 0;
+}
+```
+
 **See also**
 - [jerry_binary_operation_t](#jerry_binary_operation_t)