dust/dust-lang/tests/functions.rs

use dust_lang::*;

#[test]
fn function_call_with_type_argument() {
    assert_eq!(
        interpret(
            "test",
            "
            foobar = fn (T)(x : T) T { x }
            foobar::(int)::(42)
            ",
        ),
        Ok(Some(Value::integer(42)))
    );
}

#[test]
fn function_call() {
    assert_eq!(
        interpret(
            "test",
            "
            foobar = fn (message : str) str { message }
            foobar('Hiya')
            ",
        ),
        Ok(Some(Value::string("Hiya".to_string())))
    );
}

#[test]
fn call_empty_function() {
    assert_eq!(
        interpret(
            "test",
            "
            foobar = fn (message : str) none {}
            foobar('Hiya')
            ",
        ),
        Ok(None)
    );
}

#[test]
fn callback() {
    assert_eq!(
        interpret(
            "test",
            "
            foobar = fn (cb: fn() -> str) str {
                cb()
            }
            foobar(fn () str { 'Hiya' })
            ",
        ),
        Ok(Some(Value::string("Hiya".to_string())))
    );
}

#[test]
fn built_in_function_call() {
    assert_eq!(interpret("test", "io.write_line('Hiya')"), Ok(None));
}

#[test]
fn function_context_captures_values() {
    assert_eq!(
        interpret(
            "test",
            "
            bar = fn () int { 2 }
            foo = fn () int { bar() }
            foo()
            "
        ),
        Ok(Some(Value::integer(2)))
    );
}

#[test]
fn recursion() {
    assert_eq!(
        interpret(
            "test",
            "
            fib = fn (i: int) int {
            	if i <= 1 {
            		1
            	} else {
            		fib(i - 1) + fib(i - 2)
            	}
            }

            fib(8)
            "
        ),
        Ok(Some(Value::integer(34)))
    );
}