Functions.

examples/expressions_test.fun

@@ -8,7 +8,7 @@ print("=== Expressions test start ===")
 number a = 2
 number b = 3
 number n = 10
-string s = "Hello, world!"
+string s = "Have, fun!"
 boolean flag = true
 
 // Arithmetic and precedence

examples/functions_test.fun

@@ -0,0 +1,40 @@
+#!/usr/bin/env fun
+
+// Functions test: definitions, calls, parameters, locals, returns, and if/else.
+
+print("=== Functions test start ===")
+
+fun add(a, b)
+  return a + b
+
+fun abs(x)
+  if (x < 0)
+    return -x
+  else
+    return x
+
+fun sum3(a, b, c)
+  // local typed declaration
+  number t = a + b
+  return t + c
+
+fun id(x)
+  return x
+
+// Calls in expressions
+print(add(2, 3))             // expect 5
+print(add(10, -3))           // expect 7
+print(abs(-7))               // expect 7
+print(abs(4))                // expect 4
+print(sum3(1, 2, 3))         // expect 6
+print(add(add(1, 2), 3))     // expect 6
+print(id(42))                // expect 42
+
+// Call as statement (result discarded)
+add(100, 23)
+
+// Globals interacting with functions
+number n = 5
+print(add(n, 10))            // expect 15
+
+print("=== Functions test end ===")

examples/have_fun.fun

@@ -1,7 +1,7 @@
 #!/usr/bin/env fun
 
 /*
- * Have fun! in Fun
+ * Have fun in Fun
  */
 
- print("Hello, fun!")
+print("Have, fun!")

examples/have_fun_function.fun

@@ -0,0 +1,10 @@
+#!/usr/bin/env fun
+
+/*
+ * Have fun in Fun
+ */
+
+fun have_fun()
+  print("Have, fun!")
+
+have_fun()