1 files changed, 22 insertions, 0 deletions
diff --git a/clox/src/vm.c b/clox/src/vm.c
index 0d8d638..bf7078c 100644
--- a/clox/src/vm.c
+++ b/clox/src/vm.c
@@ -1,6 +1,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
+#include <time.h>
 
 #include "common.h"
 #include "compiler.h"
@@ -11,6 +12,10 @@
 
 VM vm;
 
+static Value clockNative(int argCount, Value *args) {
+  return NUMBER_VAL((double)clock() / CLOCKS_PER_SEC);
+}
+
 static void resetStack() {
   vm.stackTop = vm.stack;
   vm.frameCount = 0;
@@ -38,12 +43,22 @@ static void runtimeError(const char *format, ...) {
   resetStack();
 }
 
+static void defineNative(const char *name, NativeFn function) {
+  push(OBJ_VAL(copyString(name, (int)strlen(name))));
+  push(OBJ_VAL(newNative(function)));
+  tableSet(&vm.globals, AS_STRING(vm.stack[0]), vm.stack[1]);
+  pop();
+  pop();
+}
+
 void initVM() {
   resetStack();
   vm.objects = NULL;
 
   initTable(&vm.globals);
   initTable(&vm.strings);
+
+  defineNative("clock", clockNative);
 }
 
 void freeVM() {
@@ -88,6 +103,13 @@ static bool callValue(Value callee, int argCount) {
     switch (OBJ_TYPE(callee)) {
     case OBJ_FUNCTION:
       return call(AS_FUNCTION(callee), argCount);
+    case OBJ_NATIVE: {
+      NativeFn native = AS_NATIVE(callee);
+      Value result = native(argCount, vm.stackTop - argCount);
+      vm.stackTop -= argCount + 1;
+      push(result);
+      return true;
+    }
     default:
       break;
     }