Added typeof opcode to verify variable types.

examples/typeof.fun

@@ -0,0 +1,50 @@
+#!/usr/bin/env fun
+
+/*
+ * 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 ISC license.
+ * https://opensource.org/license/isc-license-txt
+ */
+
+print("=== Typeof test start ===")
+ 
+ // Array
+a = [1, 2, 3]
+print(typeof(a))
+ 
+fun f()
+  print("A function!")
+
+// Function
+print(typeof(f))
+f()
+
+// Map
+m = { "x": 1, "y": 2, "move": move }
+print(typeof(m))
+
+// Nil
+nil x = nil
+print(typeof(x))
+
+// Number
+number n = 10
+print(typeof(n)) 
+
+string s = "Have fun!"
+print(typeof(s)) 
+
+print("=== Typeof test end ===")
+
+/* Expected output:
+Array
+Function
+A function!
+Map
+Nil
+Number
+String
+*/

src/bytecode.h

@@ -72,6 +72,7 @@ typedef enum {
     // conversions
     OP_TO_NUMBER,     // pops any; pushes int (parse strings)
     OP_TO_STRING,     // pops any; pushes string
+    OP_TYPEOF,        // pops any; pushes string name of type
 
     // string ops
     OP_SPLIT,         // pops sep, string; pushes array of strings

src/parser.c

@@ -448,6 +448,14 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
                 free(name);
                 return 1;
             }
+            if (strcmp(name, "typeof") == 0) {
+                (*pos)++; /* '(' */
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "typeof expects 1 argument"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after typeof arg"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_TYPEOF, 0);
+                free(name);
+                return 1;
+            }
             if (strcmp(name, "keys") == 0) {
                 (*pos)++; /* '(' */
                 if (!emit_expression(bc, src, len, pos) || !consume_char(src, len, pos, ')')) { parser_fail(*pos, "keys expects 1 arg"); free(name); return 0; }

src/vm.c

@@ -273,6 +273,7 @@ void vm_run(VM *vm, Bytecode *entry) {
             #include "vm/print.c"
             #include "vm/to_number.c"
             #include "vm/to_string.c"
+            #include "vm/typeof.c"
 
             default:
                 if (!opcode_is_valid(inst.op)) {

src/vm.h

@@ -35,7 +35,7 @@ static const char *opcode_names[] = {
     "MOD","AND","OR","NOT","DUP","SWAP",
     "MAKE_ARRAY","INDEX_GET","INDEX_SET",
     "LEN","ARR_PUSH","ARR_POP","ARR_SET","ARR_INSERT","ARR_REMOVE","SLICE",
-    "TO_NUMBER","TO_STRING",
+    "TO_NUMBER","TO_STRING","TYPEOF",
     "SPLIT","JOIN","SUBSTR","FIND",
     "CONTAINS","INDEX_OF","CLEAR",
     "ENUMERATE","ZIP",

src/vm/typeof.c

@@ -0,0 +1,17 @@
+case OP_TYPEOF: {
+    Value v = pop_value(vm);
+    const char *tname = "Unknown";
+    switch (v.type) {
+        case VAL_INT:      tname = "Number";   break;
+        case VAL_STRING:   tname = "String";   break;
+        case VAL_FUNCTION: tname = "Function"; break;
+        case VAL_ARRAY:    tname = "Array";    break;
+        case VAL_MAP:      tname = "Map";      break;
+        case VAL_NIL:      tname = "Nil";      break;
+        default:           tname = "Unknown";  break;
+    }
+    /* push a new string value; make_string duplicates the C string */
+    push_value(vm, make_string(tname));
+    free_value(v);
+    break;
+}