Added new opcode OP_ENV to provide an env() function to get environment variables from your OS.

examples/os_env.fun

@@ -0,0 +1,18 @@
+#!/usr/bin/env fun
+
+// Environment variables via env(name):
+// - Returns the value as a string.
+// - If the variable is not set, returns an empty string.
+
+print("HOME=" + env("HOME"))
+print("SHELL=" + env("SHELL"))
+print("FUN_NOT_SET=" + env("FUN_NOT_SET"))
+
+// You can use it in scripts, e.g.:
+fun greet()
+  user = env("USER")
+  if user == ""
+    print("Hello, mysterious friend!")
+  else
+    print("Hello, " + user + "!")
+greet()

src/bytecode.h

@@ -110,7 +110,10 @@ typedef enum {
 
     // file I/O
     OP_READ_FILE,     // pops path string; pushes content string (or "")
-    OP_WRITE_FILE     // pops data string, path string; pushes 1/0
+    OP_WRITE_FILE,    // pops data string, path string; pushes 1/0
+
+    // OS
+    OP_ENV            // pops name string; pushes value string (or "")
 } OpCode;
 
 typedef struct {

src/parser.c

@@ -663,6 +663,14 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
                 free(name);
                 return 1;
             }
+            if (strcmp(name, "env") == 0) {
+                (*pos)++; /* '(' */
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "env expects 1 argument"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after env arg"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_ENV, 0);
+                free(name);
+                return 1;
+            }
             /* string ops */
             if (strcmp(name, "split") == 0) {
                 (*pos)++; /* '(' */

src/vm.c

@@ -266,6 +266,7 @@ void vm_run(VM *vm, Bytecode *entry) {
             
             #include "vm/io/read_file.c"
             #include "vm/io/write_file.c"
+            #include "vm/os/env.c"
             
             #include "vm/logic/and.c"
             #include "vm/logic/eq.c"

src/vm.h

@@ -33,7 +33,7 @@ static const char *opcode_names[] = {
     "ENUMERATE","ZIP",
     "MIN","MAX","CLAMP","ABS","POW","RANDOM_SEED","RANDOM_INT",
     "MAKE_MAP","KEYS","VALUES","HAS_KEY",
-    "READ_FILE","WRITE_FILE"
+    "READ_FILE","WRITE_FILE","ENV"
 };
 
 typedef struct {
@@ -76,7 +76,7 @@ void vm_dump_globals(VM *vm);
 void vm_run(VM *vm, Bytecode *entry);
 
 static inline int opcode_is_valid(int op) {
-    return op >= OP_NOP && op <= OP_WRITE_FILE;  // all current opcodes
+    return op >= OP_NOP && op <= OP_ENV;  // all current opcodes
 }
 
 #endif

src/vm/os/env.c

@@ -0,0 +1,14 @@
+case OP_ENV: {
+    Value key = pop_value(vm);
+    if (key.type != VAL_STRING) {
+        fprintf(stderr, "Runtime type error: ENV expects string name\n");
+        free_value(key);
+        exit(1);
+    }
+    const char *name = key.s ? key.s : "";
+    const char *val = getenv(name);
+    /* Return empty string if not set (consistent with read_file fallback style) */
+    push_value(vm, make_string(val ? val : ""));
+    free_value(key);
+    break;
+}