Added serial device support. (0.37.23)

examples/test_serial.fun

@@ -0,0 +1,50 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://fun-lang.xyz/
+ *
+ * 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: 2025-12-28
+ */
+
+// Test script for serial communication
+// This script attempts to open a virtual serial port if it exists,
+// or just demonstrates the syntax if not.
+
+fun test_serial()
+  number fd = 0
+  number baud = 9600
+  string path = "/dev/ttyUSB0"
+
+  print("Attempting to open serial port: " + path)
+  fd = serial_open(path, baud)
+
+  if fd > 0
+    print("Successfully opened serial port. FD: " + to_string(fd))
+
+    // Config: fd, data_bits, parity, stop_bits, flow_control
+    // Parity: 0=None, 1=Odd, 2=Even
+    // Flow: 0=None, 1=Hardware
+    number ok = serial_config(fd, 8, 0, 1, 0)
+    if ok
+      print("Configured serial port: 8N1, no flow control")
+
+      number sent = serial_send(fd, "HELLO SERIAL\n")
+      print("Sent " + to_string(sent) + " bytes")
+
+      // recv is blocking in this implementation
+      // data = serial_recv(fd, 100)
+      // print "Received: " + data
+    else
+      print("Failed to configure serial port")
+
+    serial_close(fd)
+    print("Closed serial port")
+  else
+    print("Could not open serial port (this is expected if /dev/ttyUSB0 doesn't exist or no permission)")
+
+test_serial()