Collection built-ins

These functions build and take apart [T] sequences.

list

list(first: T, rest: T...) -> [T]

Builds a sequence from one or more values of the same type.

Argument	Type	Requirement	Description
first	T	Required, positional	First element. Its type becomes the element type.
rest	T...	Zero or more positional	Further elements, all of the same type as the first.

Returns [T]. The values, in order.

let widths = list(80., 120., 160.);

cons

cons(value: T, tail: [T]) -> [T]

Prepends one value to an existing sequence.

Argument	Type	Requirement	Description
value	T	Required, positional	New first element.
tail	[T]	Required, positional	The rest of the sequence. The empty literal [] works for any element type.

Returns [T]. A new sequence starting with value.

let values = cons(10., cons(20., []));

head

head(sequence: [T]) -> T

Returns the first element of a sequence.

Argument	Type	Requirement	Description
sequence	[T]	Required, positional	A non-empty sequence.

Returns T. The first element.

Fails at run time if the sequence is empty.

tail

tail(sequence: [T]) -> [T]

Returns every element after the first.

Argument	Type	Requirement	Description
sequence	[T]	Required, positional	A non-empty sequence.

Returns [T]. Everything after the first element.

Fails at run time if the sequence is empty.

range_full

range_full(start: Int, stop: Int, step: Int) -> [Int]

Builds an integer range from a start, stop, and step.

Argument	Type	Requirement	Description
start	Int	Required, positional	First value.
stop	Int	Required, positional	Exclusive upper bound.
step	Int	Required, positional	Step between values.

Returns [Int]. The range as a sequence.

For the common case of counting from zero, use std::range(stop).