Simple linked list implementation in Forth

list.fs

0 constant nil
: cons  ( car cdr -- list ) here >r swap , , r> ;
: list  ( x... #x -- list ) nil swap  0 ?do cons loop ;
: list: ( x... #x "name" -- ) list constant ;

: car   ( list -- car )     @ ;
: car!  ( car list -- )     ! ;
: cdr   ( list -- cdr )     cell+ @ ;
: cdr!  ( cdr list -- )     cell+ ! ;
: list. ( list -- )         begin ?dup while dup car . cdr repeat ;
: >end  ( list -- end )     begin dup cdr while cdr repeat ;
: append ( l1 l2 -- list )  over >end cdr! ;


( Example usage )

100 200 300  3 list: foo

foo car .                   \ prints "100 "
foo cdr car .               \ prints "200 "
foo cdr cdr car .           \ prints "300 "
foo list.                   \ prints "100 200 300 "

400 500  2 list: bar

foo bar append list.        \ prints "100 200 300 400 500 "
foo list.                   \ prints "100 200 300 400 500 "
bar list.                   \ prints "400 500 "

600 700 800  3 list: baz

baz bar append list.        \ prints "600 700 800 400 500 "
444 bar car!
bar list.                   \ prints "444 500 "
foo list.                   \ prints "100 200 300 444 500 "
baz list.                   \ prints "600 700 800 444 500 "