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;; Additional library functions for TinySCHEME.
;;
;; Copyright (C) 2016 g10 Code GmbH
;;
;; This file is part of GnuPG.
;;
;; GnuPG 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.
;;
;; GnuPG 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 this program; if not, see <http://www.gnu.org/licenses/>.
(macro (assert form)
`(if (not ,(cadr form))
(begin
(display (list "Assertion failed:" (quote ,(cadr form))))
(newline)
(exit 1))))
(assert #t)
(define (filter pred lst)
(cond ((null? lst) '())
((pred (car lst))
(cons (car lst) (filter pred (cdr lst))))
(else (filter pred (cdr lst)))))
(define (any p l)
(cond ((null? l) #f)
((p (car l)) #t)
(else (any p (cdr l)))))
(define (all p l)
(cond ((null? l) #t)
((not (p (car l))) #f)
(else (all p (cdr l)))))
;; Is PREFIX a prefix of S?
(define (string-prefix? s prefix)
(and (>= (string-length s) (string-length prefix))
(string=? prefix (substring s 0 (string-length prefix)))))
(assert (string-prefix? "Scheme" "Sch"))
;; Is SUFFIX a suffix of S?
(define (string-suffix? s suffix)
(and (>= (string-length s) (string-length suffix))
(string=? suffix (substring s (- (string-length s)
(string-length suffix))
(string-length s)))))
(assert (string-suffix? "Scheme" "eme"))
;; Locate the first occurrence of needle in haystack.
(define (string-index haystack needle)
(define (index i haystack needle)
(if (= (length haystack) 0)
#f
(if (char=? (car haystack) needle)
i
(index (+ i 1) (cdr haystack) needle))))
(index 0 (string->list haystack) needle))
;; Locate the last occurrence of needle in haystack.
(define (string-rindex haystack needle)
(let ((rindex (string-index (list->string (reverse (string->list haystack)))
needle)))
(if rindex (- (string-length haystack) rindex 1) #f)))
;; Split haystack at delimiter at most n times.
(define (string-splitn haystack delimiter n)
(define (split acc haystack delimiter n)
(if (= (string-length haystack) 0)
(reverse acc)
(let ((i (string-index haystack delimiter)))
(if (not (or (eq? i #f) (= 0 n)))
(split (cons (substring haystack 0 i) acc)
(substring haystack (+ i 1) (string-length haystack))
delimiter (- n 1))
(split (cons haystack acc) "" delimiter 0)
))))
(split '() haystack delimiter n))
;; Split haystack at delimiter.
(define (string-split haystack delimiter)
(string-splitn haystack delimiter -1))
;; Trim the prefix of S containing only characters that make PREDICATE
;; true. For example (string-ltrim char-whitespace? " foo") =>
;; "foo".
(define (string-ltrim predicate s)
(let loop ((s' (string->list s)))
(if (predicate (car s'))
(loop (cdr s'))
(list->string s'))))
;; Trim the suffix of S containing only characters that make PREDICATE
;; true.
(define (string-rtrim predicate s)
(let loop ((s' (reverse (string->list s))))
(if (predicate (car s'))
(loop (cdr s'))
(list->string (reverse s')))))
;; Trim both the prefix and suffix of S containing only characters
;; that make PREDICATE true.
(define (string-trim predicate s)
(string-ltrim predicate (string-rtrim predicate s)))
(define (string-contains? s contained)
(let loop ((offset 0))
(if (<= (+ offset (string-length contained)) (string-length s))
(if (string=? (substring s offset (+ offset (string-length contained)))
contained)
#t
(loop (+ 1 offset)))
#f)))
(define (echo . msg)
(for-each (lambda (x) (display x) (display " ")) msg)
(newline))
;; Read a word from port P.
(define (read-word . p)
(list->string
(let f ()
(let ((c (apply peek-char p)))
(cond
((eof-object? c) '())
((char-alphabetic? c)
(apply read-char p)
(cons c (f)))
(else
(apply read-char p)
'()))))))
;; Read a line from port P.
(define (read-line . p)
(list->string
(let f ()
(let ((c (apply peek-char p)))
(cond
((eof-object? c) '())
((char=? c #\newline)
(apply read-char p)
'())
(else
(apply read-char p)
(cons c (f))))))))
;; Read everything from port P.
(define (read-all . p)
(list->string
(let f ()
(let ((c (apply peek-char p)))
(cond
((eof-object? c) '())
(else (apply read-char p)
(cons c (f))))))))
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