listsort, vectorsort  stable sorting of lists and vectors
LIBRARY
(import (rnrs)) ;R6RS
(import (rnrs sorting)) ;R6RS
SYNOPSIS
(listsort proc list)
(vectorsort proc vector)
DESCRIPTION
These procedures perform a stable sort of
list
or
vector
in ascending
order according to
proc.
The procedure
proc
should accept two elements and return a true value when its first
argument is strictly less than its second, and
#f
otherwise.
 Time complexity

The sorting algorithm performs O(n lg n)
calls to
proc
where n is the length of
list
or
vector.
 Side effects

The procedure
proc
should not have any side effects.
The pairing of arguments and the sequencing of calls to
proc
are not specified.
The sorting algorithm does not modify
list
or
vector.
IMPLEMENTATION NOTES
Quicksort cannot be used because it has worse time complexity than
what is required. Heapsort cannot be used either because it is not
stable. Merge sort satisfies all requirements and can be used, but
it is not the only option.
RETURN VALUES
Both of these procedures return a single value.
The
listsort
procedure returns a list, and
vectorsort
returns a vector.
The return value may be
eq?
to the argument when the argument is already sorted, and the list
returned by
listsort
may share structure with a tail of the original list.
If multiple returns occur from
listsort
or
vectorsort,
the return values returned by earlier returns are not mutated.
EXAMPLES
(listsort < '(3 5 2 1)) => (1 2 3 5)
(vectorsort < '#(3 5 2 1)) => #(1 2 3 5)
COMPATIBILITY
These procedures are unique to R6RS. Alternatives are available in
SRFI95 and SRFI132.
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.
In particular,
proc
should accept two arguments, which are elements from
list
or
vector,
and return one value.
SEE ALSO
vectorsort!(3scm)
STANDARDS
R6RS
HISTORY
These procedures first appeared in R6RS.
AUTHORS
This page is part of the
schememanpages
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.