Doubly-linked list/Definition: Difference between revisions

=={{header|PicoLisp}}==

For the list of double-cell structures described in

[[Doubly-linked list/Element definition#PicoLisp]],

we define a header structure, containing one pointer to the start

and one to the end of the list.

+------------> end

|

+--+--+-----+

| | | ---+---> start

+-----+-----+

<lang PicoLisp># Build a doubly-linked list

(de 2list @

(let Prev NIL

(let L

(make

(while (args)

(setq Prev (chain (list (next) Prev))) ) )

(cons L Prev) ) ) )

(setq *DLst (2list 'was 'it 'a 'cat 'I 'saw))</lang>

For output of the example data, see [[Doubly-linked list/Traversal#PicoLisp]].