Struct arithmetic_eval::fns::Loop

pub struct Loop;

Loop function that evaluates the provided closure one or more times.

Type

fn<T, R>(T, fn(T) -> (false, R) | (true, T)) -> R

Examples

let program = r#"
    factorial = |x| {
        loop((x, 1), |(i, acc)| {
            continue = cmp(i, 1) != -1; # i >= 1
            (continue, if(continue, (i - 1, acc * i), acc))
        })
    };
    factorial(5) == 120 && factorial(10) == 3628800
"#;
let block = F32Grammar::parse_statements(Span::new(program)).unwrap();

let mut interpreter = Interpreter::new();
interpreter
    .insert_native_fn("cmp", fns::Compare)
    .insert_native_fn("if", fns::If)
    .insert_native_fn("loop", fns::Loop);
let ret = interpreter.evaluate(&block).unwrap();
assert_eq!(ret, Value::Bool(true));

Trait Implementations

impl Clone for Loop

fn clone(&self) -> Loop

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Loop

impl Debug for Loop

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<T> NativeFn<T> for Loop where
    T: Grammar,
    T::Lit: Num + Neg<Output = T::Lit> + Pow<T::Lit, Output = T::Lit>, 

fn evaluate<'a>(
    &self,
    args: Vec<SpannedValue<'a, T>>,
    ctx: &mut CallContext<'_, 'a>
) -> EvalResult<'a, T>

Executes the function on the specified arguments.