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| | ;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 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 glob)
#:use-module (ice-9 match)
#:export (compile-glob-pattern
glob-match?))
;;; Commentary:
;;;
;;; This is a minimal implementation of "glob patterns" (info "(libc)
;;; Globbbing"). It is currently limited to simple patterns and does not
;;; support braces and square brackets, for instance.
;;;
;;; Code:
(define (wildcard-indices str)
"Return the list of indices in STR where wildcards can be found."
(let loop ((index 0)
(result '()))
(if (= index (string-length str))
(reverse result)
(loop (+ 1 index)
(case (string-ref str index)
((#\? #\*) (cons index result))
(else result))))))
(define (compile-glob-pattern str)
"Return an sexp that represents the compiled form of STR, a glob pattern
such as \"foo*\" or \"foo??bar\"."
(define flatten
(match-lambda
(((? string? str)) str)
(x x)))
(let loop ((index 0)
(indices (wildcard-indices str))
(result '()))
(match indices
(()
(flatten (cond ((zero? index)
(list str))
((= index (string-length str))
(reverse result))
(else
(reverse (cons (string-drop str index)
result))))))
((wildcard-index . rest)
(let ((wildcard (match (string-ref str wildcard-index)
(#\? '?)
(#\* '*))))
(match (substring str index wildcard-index)
("" (loop (+ 1 wildcard-index)
rest
(cons wildcard result)))
(str (loop (+ 1 wildcard-index)
rest
(cons* wildcard str result)))))))))
(define (glob-match? pattern str)
"Return true if STR matches PATTERN, a compiled glob pattern as returned by
'compile-glob-pattern'."
(let loop ((pattern pattern)
(str str))
(match pattern
((? string? literal) (string=? literal str))
(((? string? one)) (string=? one str))
(('*) #t)
(('?) (= 1 (string-length str)))
(() #t)
(('* suffix . rest)
(match (string-contains str suffix)
(#f #f)
(index (loop rest
(string-drop str
(+ index (string-length suffix)))))))
(('? . rest)
(and (>= (string-length str) 1)
(loop rest (string-drop str 1))))
((prefix . rest)
(and (string-prefix? prefix str)
(loop rest (string-drop str (string-length prefix))))))))
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