entropykit-entropia/stdlib/option.etpy

struct Option {
    is_some: u8,
    value:   u64,
}

// some - wrap a value as a present Option.
fn some(v: u64) -> Option {
    ret Option { is_some: 1, value: v };
}

// none - produce the absent Option. value is left zero.
fn none() -> Option {
    ret Option { is_some: 0, value: 0 };
}

// is_some - 1 if present, 0 if absent. Useful as the if-condition.
fn is_some(o: Option) -> int {
    if o.is_some == 0 { ret 0; }
    ret 1;
}

// is_none - inverse of is_some. Symmetric naming.
fn is_none(o: Option) -> int {
    if o.is_some == 0 { ret 1; }
    ret 0;
}

// unwrap - return the inner value, or raise 0xCE ("crashed because
// empty") if the Option was None. Use if is_some { unwrap } when
// you want to handle the absence yourself.
fn unwrap(o: Option) -> u64 {
    if o.is_some == 0 { raise 0xCE; }
    ret o.value;
}

// unwrap_or - return the inner value if present, else
// default. Branch-less from the caller's perspective; ideal for
// supplying a sentinel ("timeout = 5000 ms by default") without a temp.
fn unwrap_or(o: Option, default: u64) -> u64 {
    if o.is_some == 0 { ret default; }
    ret o.value;
}