insert-nth! ( elt n seq -- )

Vocabulary

sequences.extras

Inputs

elt	an object
n	an integer
seq	a sequence

Outputs

None

Word description

A variant of insert-nth that modifies seq in place.

Definition

USING: growable kernel math sequences sequences.private ;

IN: sequences.extras

: insert-nth! ( elt n seq -- )
    dupd [ length [ swap - 1 + ] keep ] keep ensure [
        [ [ swap - dup 1 - ] curry ] dip [ move-unsafe ] curry
        compose each-integer
    ] keep set-nth-unsafe ;