Added input_hidden() to ask for passwords in the CLI without echoing the chars. (0.37.37)

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.10)
-project(fun VERSION 0.37.36 LANGUAGES C)
+project(fun VERSION 0.37.37 LANGUAGES C)
 
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED ON)

examples/input_hidden_example.fun

@@ -0,0 +1,29 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://fun-lang.xyz/
+ *
+ * Example: Demonstrate hidden input (no echo) for passwords.
+ *
+ * Added: 2026-01-02
+ */
+
+#include <io/console.fun>
+
+print("=== input_hidden() example ===")
+
+c = Console()
+
+username = c.ask("Username")
+password = c.ask_hidden("Password")
+
+// Do not print the password; just show the username
+print(join(["Hello, ", username, "!"], ""))
+
+/* Expected output:
+Username: hanez
+Password:
+=== input_hidden() example ===
+Hello, hanez!
+*/

examples/input_hidden_pam_auth.fun

@@ -0,0 +1,45 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://fun-lang.xyz/
+ *
+ * Example: Demonstrate hidden input (no echo) for passwords using
+ * /usr/bin/chkpwd from https://git.xw3.org/hanez/chkusr for PAM authetication.
+ *
+ * Added: 2026-01-02
+ */
+
+#include <io/console.fun>
+
+print("=== input_hidden() example with PAM authentication ===")
+
+c = Console()
+
+username = c.ask("Username")
+password = c.ask_hidden("Password")
+
+// Do not print the password; just show the username
+print(join(["Hello, ", username, "!"], ""))
+
+res = proc_run("chkpwd -u " + username + " -p " + password)
+content = res["out"]
+if (res["code"] == 0)
+  print("Login success!")
+else
+  print("Login failed!")
+
+/* Possible output:
+Username: hanez
+Password:
+=== input_hidden() example with PAM authentication ===
+Hello, hanez!
+Login success!
+
+Or:
+Username: hanez
+Password: 
+=== input_hidden() example with PAM authentication ===
+Hello, hanez!
+Login failed!
+*/

lib/io/console.fun

@@ -17,6 +17,15 @@ class Console()
     else
       return input(join([q, ": "], ""))
 
+  // Ask for a secret string (e.g., password) without echoing input
+  // Returns the entered string. A trailing newline is not echoed back.
+  fun ask_hidden(this, question)
+    q = to_string(question)
+    if (len(q) == 0)
+      return input_hidden("")
+    else
+      return input_hidden(join([q, ": "], ""))
+
   // Ask a yes/no question; returns 1 for yes, 0 for no
   // Accepts: y, yes, n, no (case-insensitive). Keeps asking until valid.
   fun ask_yes_no(this, question)

src/parser.c

@@ -709,6 +709,20 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
                 free(name);
                 return 1;
             }
+            if (strcmp(name, "input_hidden") == 0) {
+                (*pos)++; /* '(' */
+                int hasPrompt = 0;
+                skip_spaces(src, len, pos);
+                if (*pos < len && src[*pos] != ')') {
+                    if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "input_hidden expects 0 or 1 argument"); free(name); return 0; }
+                    hasPrompt = 1;
+                }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after input_hidden arg(s)"); free(name); return 0; }
+                /* operand bit0 = hasPrompt, bit1 = hidden */
+                bytecode_add_instruction(bc, OP_INPUT_LINE, (hasPrompt ? 1 : 0) | 2);
+                free(name);
+                return 1;
+            }
             if (strcmp(name, "proc_run") == 0) {
                 (*pos)++; /* '(' */
                 if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "proc_run expects 1 argument (command string)"); free(name); return 0; }

src/vm.c

@@ -29,9 +29,15 @@
 #include <netdb.h>
 #include <sys/un.h>
 #include <unistd.h>
+/* For hidden input (password) handling in OP_INPUT_LINE */
+#include <termios.h>
 //#include <arpa/inet.h>
 #endif
 
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
 /* Bring in split-out built-ins without changing the build system yet */
 #include "iter.c"
 #include "map.c"

src/vm/io/input_line.c

@@ -1,6 +1,10 @@
 case OP_INPUT_LINE: {
-    /* operand: 0 = no prompt; 1 = has prompt (string or any value convertible to string) */
+    /* operand bit flags:
-    int has_prompt = inst.operand ? 1 : 0;
+     *  bit0 (1): has prompt (string or any value convertible to string) — top of stack holds prompt when set
+     *  bit1 (2): hidden input (do not echo typed characters)
+     */
+    int has_prompt = (inst.operand & 1) ? 1 : 0;
+    int hidden = (inst.operand & 2) ? 1 : 0;
     if (has_prompt) {
         /* pop prompt value and print without newline */
         Value pv = pop_value(vm);
@@ -13,6 +17,35 @@ case OP_INPUT_LINE: {
         free_value(pv);
     }
 
+    /* For hidden input, temporarily disable terminal echo if possible */
+    int echo_disabled = 0;
+#ifdef _WIN32
+    if (hidden) {
+        HANDLE hStdin = GetStdHandle(STD_INPUT_HANDLE);
+        if (hStdin != INVALID_HANDLE_VALUE) {
+            DWORD mode;
+            if (GetConsoleMode(hStdin, &mode)) {
+                DWORD newMode = mode & ~(ENABLE_ECHO_INPUT);
+                if (SetConsoleMode(hStdin, newMode)) {
+                    echo_disabled = 1;
+                }
+            }
+        }
+    }
+#else
+    if (hidden) {
+        /* POSIX termios */
+        struct termios oldt;
+        if (tcgetattr(STDIN_FILENO, &oldt) == 0) {
+            struct termios newt = oldt;
+            newt.c_lflag &= ~(ECHO);
+            if (tcsetattr(STDIN_FILENO, TCSANOW, &newt) == 0) {
+                echo_disabled = 1;
+            }
+        }
+    }
+#endif
+
     /* read a line from stdin, dynamically grow buffer */
     size_t cap = 128;
     size_t len = 0;
@@ -20,7 +53,8 @@ case OP_INPUT_LINE: {
     if (!buf) {
         fprintf(stderr, "Runtime error: out of memory reading input");
         push_value(vm, make_string(""));
-        break;
+        /* On early exit, try to restore echo if we turned it off */
+        goto restore_echo_and_break;
     }
 
     int ch;
@@ -68,5 +102,36 @@ case OP_INPUT_LINE: {
     free(buf);
 
 push_done:
+    /* If we disabled echo, restore terminal settings and print a newline for UX */
+#ifdef _WIN32
+    if (echo_disabled) {
+        HANDLE hStdin = GetStdHandle(STD_INPUT_HANDLE);
+        if (hStdin != INVALID_HANDLE_VALUE) {
+            DWORD mode;
+            if (GetConsoleMode(hStdin, &mode)) {
+                /* Re-enable ECHO flag */
+                mode |= ENABLE_ECHO_INPUT;
+                SetConsoleMode(hStdin, mode);
+            }
+        }
+        if (has_prompt) {
+            fputc('\n', stdout);
+            fflush(stdout);
+        }
+    }
+#else
+    if (echo_disabled) {
+        struct termios t;
+        if (tcgetattr(STDIN_FILENO, &t) == 0) {
+            t.c_lflag |= ECHO;
+            tcsetattr(STDIN_FILENO, TCSANOW, &t);
+        }
+        if (has_prompt) {
+            fputc('\n', stdout);
+            fflush(stdout);
+        }
+    }
+#endif
+restore_echo_and_break:
     break;
 }