scsh-0.6/scheme/big/filename.scm

116 lines
3.3 KiB
Scheme

; Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees. See file COPYING.
; Silly file name utilities
; These try to be operating-system independent, but fail, of course.
; Namelist = ((dir ...) basename type)
; or ((dir ...) basename)
; or (dir basename type)
; or (dir basename)
; or basename
(define (namestring namelist dir default-type)
(let* ((namelist (if (list? namelist) namelist (list '() namelist)))
(subdirs (if (list? (car namelist))
(car namelist)
(list (car namelist))))
(basename (cadr namelist))
(type (if (null? (cddr namelist))
(if (string? basename)
#f
default-type)
(caddr namelist))))
(string-append (or dir "")
(apply string-append
(map (lambda (subdir)
(string-append
(namestring-component subdir)
directory-component-separator))
subdirs))
(namestring-component basename)
(if type
(string-append type-component-separator
(namestring-component type))
""))))
(define directory-component-separator "/") ;unix sux
(define type-component-separator ".")
(define (namestring-component x)
(cond ((string? x) x)
((symbol? x)
(list->string (map file-name-preferred-case
(string->list (symbol->string x)))))
(else (error "bogus namelist component" x))))
(define file-name-preferred-case char-downcase)
(define *scheme-file-type* 'scm)
(define *load-file-type* *scheme-file-type*) ;#F for Pseudoscheme or T
; Interface copied from gnu emacs:
;file-name-directory
; Function: Return the directory component in file name NAME.
;file-name-nondirectory
; Function: Return file name NAME sans its directory.
;file-name-absolute-p
; Function: Return t if file FILENAME specifies an absolute path name.
;substitute-in-file-name
; Function: Substitute environment variables referred to in STRING.
;expand-file-name
; Function: Convert FILENAME to absolute, and canonicalize it.
(define (file-name-directory filename)
(substring filename 0 (file-nondirectory-position filename)))
(define (file-name-nondirectory filename)
(substring filename
(file-nondirectory-position filename)
(string-length filename)))
(define (file-nondirectory-position filename)
(let loop ((i (- (string-length filename) 1)))
(cond ((< i 0) 0)
;; Heuristic. Should work for DOS, Unix, VMS, MacOS.
((string-posq (string-ref filename i) "/:>]\\") (+ i 1))
(else (loop (- i 1))))))
(define (string-posq thing s)
(let loop ((i 0))
(cond ((>= i (string-length s)) #f)
((eq? thing (string-ref s i)) i)
(else (loop (+ i 1))))))
; Directory translations.
; E.g. (set-translation! "foo;" "/usr/mumble/foo/")
(define *translations* '())
(define (translations) *translations*)
(define (set-translation! from to)
(let ((probe (assoc from *translations*)))
(if probe
(set-cdr! probe to)
(set! *translations* (cons (cons from to) *translations*)))))
(define (translate name)
(let ((len (string-length name)))
(let loop ((ts *translations*))
(if (null? ts)
name
(let* ((from (caar ts))
(to (cdar ts))
(k (string-length from)))
(if (and to
(<= k len)
(string=? (substring name 0 k) from))
(string-append to (substring name k len))
(loop (cdr ts))))))))