Some more stdlib fun and example code and cosmetic changes. (0.38.15)

examples/error_handling.fun

@@ -0,0 +1,64 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://fun-lang.xyz/
+ *
+ * Copyright 2026 Johannes Findeisen
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2026-02-19
+ */
+
+/*
+ * Error handling examples using Result and Option helpers.
+ */
+
+#include <utils/option.fun>
+#include <utils/result.fun>
+
+// Simulate a fallible parse
+fun parse_int(s)
+  if regex_match("^[+-]?[0-9]+$", s)
+    return ok(to_number(s))
+  return err("invalid integer: " + s)
+
+// Divide two integers, handling division by zero
+fun safe_div(a, b)
+  if b == 0
+    return err("division by zero")
+  return ok(a / b)
+
+// Option example: get environment variable
+fun get_env_opt(name)
+  v = env(name)
+  if v == nil
+    return none()
+  if v == ""
+    return none()
+  return some(v)
+
+print("-- Result examples --")
+r = parse_int("123")
+print("parse_int 123 ok? " + to_string(is_ok(r)) + ", value: " + to_string(unwrap_or(r, -1)))
+
+q = parse_int("x12")
+print("parse_int x12 ok? " + to_string(is_ok(q)) + ", or default 0: " + to_string(unwrap_or(q, 0)))
+
+print("chained and_then: '10' / '2'")
+// Simpler explicit flow without nested anonymous functions
+a = parse_int("10")
+b = parse_int("2")
+if is_ok(a) && is_ok(b)
+  res = safe_div(unwrap(a), unwrap(b))
+else
+  if is_err(a)
+    res = a
+  else
+    res = b
+print("=> ok? " + to_string(is_ok(res)) + ", value: " + to_string(unwrap_or(res, -1)))
+
+print("-- Option examples --")
+home = get_env_opt("HOME")
+print("HOME is set? " + to_string(is_some(home)) + ", value: " + to_string(unwrap_or(home, "<none>")))