append - append an object to one or multiple lists
LIBRARY
(import (rnrs)) ;R6RS
(import (rnrs base)) ;R6RS
(import (scheme r5rs)) ;R7RS
(import (scheme base)) ;R7RS
SYNOPSIS
(append)
(append list ... obj)
DESCRIPTION
Returns a possibly improper list consisting of the elements
of the first
list
followed by the elements of the other
lists,
with
obj
as the cdr of the final pair.
An improper list
results if
obj
is not a list. Returns the empty list if called with no arguments.
The return value is made from new pairs for all arguments
but the last; the last is merely placed at the end of the new
structure.
RETURN VALUES
Returns a single value. An improper list results if
obj
is not a proper list.
EXAMPLES
(append '(x) '(y)) => (x y)
(append '(a) '(b c d)) => (a b c d)
(append '(a (b)) '((c))) => (a (b) (c))
(append '(a b) '(c . d)) => (a b c . d)
(append '() 'a) => a
(append) => ()
(append 'a) => a
COMPATIBILITY
Except for differences in error behavior, this procedure works the
same everywhere.
ERRORS
This procedure can raise exceptions with the following condition types:
- &assertion (R6RS)
-
The wrong number of arguments was passed or an argument was outside its domain.
- R7RS
-
The assertions described above are errors.
Implementations may signal an error, extend the procedure's
domain of definition to include such arguments,
or fail catastrophically.
SEE ALSO
cons*(3scm),
cons(3scm),
list-tail(3scm)
STANDARDS
R4RS,
IEEE Scheme,
R5RS,
R6RS,
R7RS
HISTORY
The
append
procedure has existed in LISP since at least 1959.
The variants before R3RS only accepted proper lists.
Scheme before R2RS running on MacLISP accept any number of argments,
while in LISP 1.5 the procedure only accepted two arguments.
AUTHORS
This page is part of the
scheme-manpages
project.
It includes materials from the RnRS documents.
More information can be found at
https://github.com/schemedoc/manpages/.
Markup created by unroff 1.0sc, March 04, 2023.