mirror of
https://git.in.rschanz.org/ryan77627/guix.git
synced 2024-11-13 18:36:14 -05:00
d326767e64
* guix/sets.scm, tests/sets.scm: New files.sets * Makefile.am (MODULES, SCM_TESTS): Add them.
116 lines
3.5 KiB
Scheme
116 lines
3.5 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
|
|
;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
|
|
;;;
|
|
;;; This file is part of GNU Guix.
|
|
;;;
|
|
;;; GNU Guix is free software; you can redistribute it and/or modify it
|
|
;;; under the terms of the GNU General Public License as published by
|
|
;;; the Free Software Foundation; either version 3 of the License, or (at
|
|
;;; your option) any later version.
|
|
;;;
|
|
;;; GNU Guix is distributed in the hope that it will be useful, but
|
|
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
;;; GNU General Public License for more details.
|
|
;;;
|
|
;;; You should have received a copy of the GNU General Public License
|
|
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
(define-module (guix sets)
|
|
#:use-module (srfi srfi-1)
|
|
#:use-module (srfi srfi-9)
|
|
#:use-module (srfi srfi-26)
|
|
#:use-module (ice-9 vlist)
|
|
#:use-module (ice-9 match)
|
|
#:export (set
|
|
setq
|
|
set?
|
|
set-insert
|
|
set-union
|
|
set-contains?
|
|
set->list
|
|
list->set
|
|
list->setq))
|
|
|
|
;;; Commentary:
|
|
;;;
|
|
;;; A simple (simplistic?) implementation of unordered persistent sets based
|
|
;;; on vhashes that seems to be good enough so far.
|
|
;;;
|
|
;;; Another option would be to use "bounded balance trees" (Adams 1992) as
|
|
;;; implemented by Ian Price in 'pfds', which has faster union etc. but needs
|
|
;;; an order on the objects of the set.
|
|
;;;
|
|
;;; Code:
|
|
|
|
(define-record-type <set>
|
|
(%make-set vhash insert ref)
|
|
set?
|
|
(vhash set-vhash)
|
|
(insert set-insert-proc)
|
|
(ref set-ref))
|
|
|
|
(define %insert
|
|
(cut vhash-cons <> #t <>))
|
|
(define %insertq
|
|
(cut vhash-consq <> #t <>))
|
|
|
|
(define (set . args)
|
|
"Return a set containing the ARGS, compared as per 'equal?'."
|
|
(list->set args))
|
|
|
|
(define (setq . args)
|
|
"Return a set containing the ARGS, compared as per 'eq?'."
|
|
(list->setq args))
|
|
|
|
(define (list->set lst)
|
|
"Return a set with the elements taken from LST. Elements of the set will be
|
|
compared with 'equal?'."
|
|
(%make-set (fold %insert vlist-null lst)
|
|
%insert
|
|
vhash-assoc))
|
|
|
|
(define (list->setq lst)
|
|
"Return a set with the elements taken from LST. Elements of the set will be
|
|
compared with 'eq?'."
|
|
(%make-set (fold %insertq vlist-null lst)
|
|
%insertq
|
|
vhash-assq))
|
|
|
|
(define-inlinable (set-contains? set value)
|
|
"Return #t if VALUE is a member of SET."
|
|
(->bool ((set-ref set) value (set-vhash set))))
|
|
|
|
(define (set-insert value set)
|
|
"Insert VALUE into SET."
|
|
(if (set-contains? set value)
|
|
set
|
|
(let ((vhash ((set-insert-proc set) value (set-vhash set))))
|
|
(%make-set vhash (set-insert-proc set) (set-ref set)))))
|
|
|
|
(define-inlinable (set-size set)
|
|
"Return the number of elements in SET."
|
|
(vlist-length (set-vhash set)))
|
|
|
|
(define (set-union set1 set2)
|
|
"Return the union of SET1 and SET2. Warning: this is linear in the number
|
|
of elements of the smallest."
|
|
(unless (eq? (set-insert-proc set1) (set-insert-proc set2))
|
|
(error "set-union: incompatible sets"))
|
|
|
|
(let* ((small (if (> (set-size set1) (set-size set2))
|
|
set2 set1))
|
|
(large (if (eq? small set1) set2 set1)))
|
|
(vlist-fold (match-lambda*
|
|
(((item . _) result)
|
|
(set-insert item result)))
|
|
large
|
|
(set-vhash small))))
|
|
|
|
(define (set->list set)
|
|
"Return the list of elements of SET."
|
|
(map (match-lambda
|
|
((key . _) key))
|
|
(vlist->list (set-vhash set))))
|
|
|
|
;;; sets.scm ends here
|