xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/guile/lib/gdb/iterator.scm (revision 3117ece4fc4a4ca4489ba793710b60b0d26bab6c)
1;; Iteration utilities.
2;; Anything in this file can change or disappear.
3;;
4;; Copyright (C) 2014-2023 Free Software Foundation, Inc.
5;;
6;; This file is part of GDB.
7;;
8;; This program is free software; you can redistribute it and/or modify
9;; it under the terms of the GNU General Public License as published by
10;; the Free Software Foundation; either version 3 of the License, or
11;; (at your option) any later version.
12;;
13;; This program is distributed in the hope that it will be useful,
14;; but WITHOUT ANY WARRANTY; without even the implied warranty of
15;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16;; GNU General Public License for more details.
17;;
18;; You should have received a copy of the GNU General Public License
19;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
20
21(define-module (gdb iterator)
22  #:use-module (gdb)
23  #:use-module (gdb support))
24
25(define-public (make-list-iterator l)
26  "Return a <gdb:iterator> object for a list."
27  (assert-type (list? l) l SCM_ARG1 'make-list-iterator "list")
28  (let ((next! (lambda (iter)
29		 (let ((l (iterator-progress iter)))
30		   (if (eq? l '())
31		       (end-of-iteration)
32		       (begin
33			 (set-iterator-progress! iter (cdr l))
34			 (car l)))))))
35    (make-iterator l l next!)))
36
37(define-public (iterator->list iter)
38  "Return the elements of ITER as a list."
39  (let loop ((iter iter)
40	     (result '()))
41    (let ((next (iterator-next! iter)))
42      (if (end-of-iteration? next)
43	  (reverse! result)
44	  (loop iter (cons next result))))))
45
46(define-public (iterator-map proc iter)
47  "Return a list of PROC applied to each element."
48  (let loop ((proc proc)
49	     (iter iter)
50	     (result '()))
51    (let ((next (iterator-next! iter)))
52      (if (end-of-iteration? next)
53	  (reverse! result)
54	  (loop proc iter (cons (proc next) result))))))
55
56(define-public (iterator-for-each proc iter)
57  "Apply PROC to each element.  The result is unspecified."
58  (let ((next (iterator-next! iter)))
59    (if (not (end-of-iteration? next))
60	(begin
61	  (proc next)
62	  (iterator-for-each proc iter)))))
63
64(define-public (iterator-filter pred iter)
65  "Return the elements that satify predicate PRED."
66  (let loop ((result '()))
67    (let ((next (iterator-next! iter)))
68      (cond ((end-of-iteration? next) (reverse! result))
69	    ((pred next) (loop (cons next result)))
70	    (else (loop result))))))
71
72(define-public (iterator-until pred iter)
73  "Run the iterator until the result of (pred element) is true.
74
75  Returns:
76    The result of the first (pred element) call that returns true,
77    or #f if no element matches."
78  (let loop ((next (iterator-next! iter)))
79    (cond ((end-of-iteration? next) #f)
80	  ((pred next) => identity)
81	  (else (loop (iterator-next! iter))))))
82