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#! /bin/sh
# -*-scheme-*-
mes_p=$(command -v mes)
if [ "$mes_p" -a -z "$MES" ]; then
MES=guile
fi
exec ${MES-mes} -L ${0%/*} -e '(diff)' -s "$0" "$@"
!#
;;; GNU Mes --- Maxwell Equations of Software
;;; Copyright © 2016,2017,2018 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; mes-snarf.scm: This file is part of GNU Mes.
;;;
;;; GNU Mes 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 Mes 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 Mes. If not, see <http://www.gnu.org/licenses/>.
(define-module (diff)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (ice-9 rdelim)
#:export (main))
(cond-expand
(mes
(define %scheme "mes"))
(guile-2
(define %scheme "guile")
(define-macro (mes-use-module . rest) #t))
(guile
(use-modules (ice-9 syncase))
(define %scheme "guile")
(define-macro (mes-use-module . rest) #t)))
(mes-use-module (mes guile))
(format (current-error-port) "diff[~a]...\n" %scheme)
(define (plus a)
(string-append "+" a))
(define (minus a)
(string-append "-" a))
(define (keep a)
(string-append " " a))
(define-record-type <hunk> (make-hunk context after removed added)
hunk?
(context hunk.context)
(after hunk.after)
(removed hunk.removed)
(added hunk.added))
(define (hunk->lines o)
(append `(,(format #f "@@ -~a,~a +~a,~a" (length (hunk.removed o)) (+ 3 (car (hunk.context o))) (length (hunk.added o)) (+ 3 (cadr (hunk.context o))))
,@(map keep (filter identity (cddr (hunk.context o)))))
(map minus (hunk.removed o))
(map plus (hunk.added o))
(map keep (hunk.after o))))
(define (safe-list-head lst n)
(list-head lst (min n (length lst))))
(define (line-equal? a b)
(equal? (string-trim-right a) (string-trim-right b)))
(define (diff-files a b)
(let ((a-lines (string-split (with-input-from-file a read-string) #\newline))
(b-lines (string-split (with-input-from-file b read-string) #\newline)))
(let loop ((context '(1 1 #f #f #f)) (a-lines a-lines) (b-lines b-lines))
;;(format (current-error-port) "loop context=~s\n" context)
(cond ((and (null? a-lines) (null? b-lines)) '())
((null? a-lines)
(list (make-hunk context (safe-list-head a-lines 3) '() b-lines)))
((null? b-lines)
(list (make-hunk context (safe-list-head a-lines 3) a-lines '())))
((line-equal? (car a-lines) (car b-lines))
(loop `(,(1+ (car context))
,(1+ (cadr context))
,@(cdddr context)
,(car a-lines))
(cdr a-lines) (cdr b-lines)))
(else
(cond ((and (pair? (cdr b-lines)) (line-equal? (car a-lines) (cadr b-lines)))
(cons (make-hunk context (safe-list-head a-lines 3) '() (list (car b-lines)))
(loop `(,(+ 1 (car context))
,(+ 2 (cadr context))
,@(cdddr context)
,(car a-lines))
(cdr a-lines) (cddr b-lines))))
((and (pair? (cdr a-lines)) (line-equal? (cadr a-lines) (car b-lines)))
(cons (make-hunk context (safe-list-head a-lines 3) (list (car a-lines)) '())
(loop `(,(+ 2 (car context))
,(+ 1 (cadr context))
,@(cddddr context)
,(car a-lines)
,(cadr a-lines))
(cddr a-lines) (cdr b-lines))))
(else (cons (make-hunk context (safe-list-head a-lines 3) (list (car a-lines)) (list (car b-lines)))
(loop `(,(1+ (car context))
,(1+ (cadr context))
,@(cdddr context)
,(car a-lines))
(cdr a-lines) (cdr b-lines))))))))))
(define (main args)
(let ((files (cdr args)))
(when (or (null? files)
(equal? (car files) "-h")
(equal? (car files) "--help"))
(display "
Usage: diff.scm [OPTION]... FILES
Compare FILES line by line.
Options:
-u,--unified display unified diff (default)
-h,--help display this help and exit
-V,--version display version information and exit
")
(exit (if (null? files) 2 0)))
(when (or (equal? (car files) "-V")
(equal? (car files) "--version"))
(display "
diff.scm (GNU Mes) 0.20
"))
(let* ((files (if (string-prefix? "-" (car files)) (cdr files) files))
(hunks (apply diff-files (list-head files 2))))
(when (pair? hunks)
(display (string-join (append-map hunk->lines hunks) "\n"))
(newline)
(exit 1)))))
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