transfer ( deque -- item newdeque )

Vocabulary

persistent.deques.private

Inputs

deque

an object

Outputs

item	an object
newdeque	an object

Definition

USING: accessors kernel lists persistent.deques ;

IN: persistent.deques.private

: transfer ( deque -- item newdeque )
    back>> dup nil?
    [ "Popping from an empty deque" throw ]
    [ split-reverse deque boa remove ] if ; inline