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|
;
; Copyright © 2018 Keith Packard <keithp@keithp.com>
;
; This program 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 2 of the License, or
; (at your option) any later version.
;
; This program 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.
;
; string functions placed in ROM
(define string-map
(lambda (proc . strings)
; result length is min of arg lengths
(let* ((l (apply min (map string-length strings)))
; create the result
(s (make-string l)))
; walk the strings, doing evaluation
(define (_m p)
(if (equal? p l)
s
(begin
(string-set! s p (apply proc (map (lambda (s) (string-ref s p)) strings)))
(_m (+ p 1))
)
)
)
(_m 0)
)
)
)
(_??_ (string-map (lambda (x) (+ 1 x)) "HAL") "IBM")
(define string-copy!
(lambda (t a f . args)
(let ((l 0)
(h (string-length f))
(o a)
(d 1))
; handle optional start/end args
(if (not (null? args))
(begin
(set! l (car args))
(if (not (null? (cdr args)))
(set! h (cadr args)))
(set! o (- a l))
)
)
; flip copy order if dst is
; after src
(if (< l a)
(begin
(set! d h)
(set! h (- l 1))
(set! l (- d 1))
(set! d -1)
)
)
; loop copying one at a time
(do ((p l (+ p d))
)
((= p h) t)
(string-set! t (+ p o) (string-ref f p))
)
)
)
)
(_??_ (string-copy! (make-string 10) 0 "hello" 0 5) "hello ")
(_??_ (string-copy! (make-string 10) 1 "hello" 0 5) " hello ")
(_??_ (string-copy! (make-string 10) 0 "hello" 0 5) "hello ")
(define (string-upcase s) (string-map char-upcase s))
(define (string-downcase s) (string-map char-downcase s))
(define string-foldcase string-downcase)
(define string-copy
(lambda (s . args)
(let ((l 0)
(h (string-length s)))
(if (not (null? args))
(begin
(set! l (car args))
(if (not (null? (cdr args)))
(set! h (cadr args)))
)
)
(string-copy! (make-string (- h l)) 0 s l h)
)
)
)
(_??_ (string-copy "hello" 0 1) "h")
(_??_ (string-copy "hello" 1) "ello")
(_??_ (string-copy "hello") "hello")
(define substring string-copy)
(define string-fill!
(lambda (s a . args)
(let ((l 0)
(h (string-length s)))
(cond ((not (null? args))
(set! l (car args))
(cond ((not (null? (cdr args)))
(set! h (cadr args)))
)
)
)
(define (_f b)
(cond ((< b h)
(string-set! s b a)
(_f (+ b 1))
)
(else s)
)
)
(_f l)
)
)
)
(_??_ (string-fill! (make-string 10) #\a) "aaaaaaaaaa")
(_??_ (string-fill! (make-string 10) #\a 1 2) " a ")
(define string-for-each
(lambda (proc . strings)
; result length is min of arg lengths
(let* ((l (apply min (map string-length strings)))
)
; walk the strings, doing evaluation
(define (_m p)
(if (equal? p l)
#t
(begin
(apply proc (map (lambda (s) (string-ref s p)) strings))
(_m (+ p 1))
)
)
)
(_m 0)
)
)
)
(_??_ (string-for-each write-char "IBM\n") #t)
|
