36-new-signatures.frtf

class List <T?>

#> Represents a list with an event number of elements, treated as pairs.
#| This is similar to a hash with ordered keys.

#> True if the list is empty.
prop .empty -> Bool {
    return @length == 0
}

#> Returns a copy of the list by mapping each element to another value based on
#| a transformation code.
func .map($code: Code) -> List {
    return gather for $el in *self {
        take $code($el)
    }
}

#> Removes all elements equal to a specified value.
func .removeAll($what) -> ($found: List, $removed: Num) {
    $found -> gather for ($i, $el) in *self {
        if $what != $el:
            next
        # FIXME: delete *self[$i]
        take $el
    }
    $removed -> $found.length #< number of removed elements
}

#> Returns true if at least one element satisfies a code.
func .any($code: Code) -> Bool {
    for $el in *self {
        if $code($el): return true
    }
    return false
}

prop .iterator -> Iterator {
    return ListIterator(*self)
}