Added EXIT opcode to make it possible to return exit codes to the shell. (0.21.4)

src/vm/core/exit.c

@@ -0,0 +1,41 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/**
+* @file exit.c
+ * @brief Implements the OP_EXIT opcode to terminate the script with an exit code.
+ *
+ * Behavior:
+ * - Pops a value from the stack (if available) and converts it to an integer exit code.
+ * - Sets vm->exit_code.
+ * - Stops the VM execution immediately (returns from vm_run).
+ */
+
+case OP_EXIT: {
+    int code = 0;
+    if (vm->sp >= 0) {
+        Value v = pop_value(vm);
+        if (v.type == VAL_INT) {
+            code = (int)v.i;
+        } else if (v.type == VAL_STRING) {
+            /* best-effort parse number from string */
+            code = (int)strtoll(v.s, NULL, 10);
+        } else if (v.type == VAL_NIL) {
+            code = 0;
+        } else {
+            /* unsupported type for exit; default to 0 */
+            code = 0;
+        }
+        free_value(v);
+    }
+    vm->exit_code = code;
+    return;
+}