oop/goops/util.scm

   1 ;;;;    Copyright (C) 1999, 2000 Free Software Foundation, Inc.
   2 ;;;;
   3 ;;;; This program is free software; you can redistribute it and/or modify
   4 ;;;; it under the terms of the GNU General Public License as published by
   5 ;;;; the Free Software Foundation; either version 2, or (at your option)
   6 ;;;; any later version.
   7 ;;;;
   8 ;;;; This program is distributed in the hope that it will be useful,
   9 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 ;;;; GNU General Public License for more details.
  12 ;;;;
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  14 ;;;; along with this software; see the file COPYING.  If not, write to
  15 ;;;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16 ;;;; Boston, MA 02111-1307 USA
  17 ;;;;
  18 \f
  19
  20 (define-module (oop goops util)
  21   :no-backtrace
  22   )
  23
  24 (export any every filter
  25         mapappend find-duplicate top-level-env top-level-env?
  26         map* for-each* length* improper->proper
  27  )
  28
  29 ;;;
  30 ;;; {Utilities}
  31 ;;;
  32
  33 (define (any pred lst . rest)
  34   (if (null? rest) ;fast path
  35       (and (not (null? lst))
  36            (let loop ((head (car lst)) (tail (cdr lst)))
  37              (if (null? tail)
  38                  (pred head)
  39                  (or (pred head)
  40                      (loop (car tail) (cdr tail))))))
  41       (let ((lsts (cons lst rest)))
  42         (and (not (any null? lsts))
  43              (let loop ((heads (map car lsts)) (tails (map cdr lsts)))
  44                (if (any null? tails)
  45                    (apply pred heads)
  46                    (or (apply pred heads)
  47                        (loop (map car tails) (map cdr tails)))))))))
  48
  49 (define (every pred lst . rest)
  50   (if (null? rest) ;fast path
  51       (or (null? lst)
  52           (let loop ((head (car lst)) (tail (cdr lst)))
  53             (if (null? tail)
  54                 (pred head)
  55                 (and (pred head)
  56                      (loop (car tail) (cdr tail))))))
  57       (let ((lsts (cons lst rest)))
  58         (or (any null? lsts)
  59             (let loop ((heads (map car lsts)) (tails (map cdr lsts)))
  60               (if (any null? tails)
  61                   (apply pred heads)
  62                   (and (apply pred heads)
  63                        (loop (map car tails) (map cdr tails)))))))))
  64
  65 (define (filter test? list)
  66   (cond ((null? list) '())
  67         ((test? (car list)) (cons (car list) (filter test? (cdr list))))
  68         (else (filter test? (cdr list)))))
  69
  70 (define (mapappend func . args)
  71   (if (memv '()  args)
  72       '()
  73       (append (apply func (map car args))
  74               (apply mapappend func (map cdr args)))))
  75
  76 (define (find-duplicate l)      ; find a duplicate in a list; #f otherwise
  77   (cond
  78     ((null? l)                  #f)
  79     ((memv (car l) (cdr l))     (car l))
  80     (else                       (find-duplicate (cdr l)))))
  81
  82 (define (top-level-env)
  83   (if *top-level-lookup-closure*
  84       (list *top-level-lookup-closure*)
  85       '()))
  86
  87 (define (top-level-env? env)
  88   (or (null? env)
  89       (procedure? (car env))))
  90
  91 (define (map* fn . l)           ; A map which accepts dotted lists (arg lists
  92   (cond                         ; must be "isomorph"
  93    ((null? (car l)) '())
  94    ((pair? (car l)) (cons (apply fn      (map car l))
  95                           (apply map* fn (map cdr l))))
  96    (else            (apply fn l))))
  97
  98 (define (for-each* fn . l)      ; A for-each which accepts dotted lists (arg lists
  99   (cond                         ; must be "isomorph"
 100    ((null? (car l)) '())
 101    ((pair? (car l)) (apply fn (map car l)) (apply for-each* fn (map cdr l)))
 102    (else            (apply fn l))))
 103
 104 (define (length* ls)
 105   (do ((n 0 (+ 1 n))
 106        (ls ls (cdr ls)))
 107       ((not (pair? ls)) n)))
 108
 109 (define (improper->proper ls)
 110   (if (pair? ls)
 111       (cons (car ls) (improper->proper (cdr ls)))
 112       (list ls)))