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authorLudovic Court`es2007-03-08 14:37:05 +0000
committerLudovic Court`es2007-03-08 14:37:05 +0000
commita456e009f1cb0e05d74adac3ad8b3092a280b054 (patch)
treee1fc14269edcd7869a76ebfba4315e18154cf9f7 /src/guile
parent99954d10bac0c40986e85e5d05c2ecd3903d7f9c (diff)
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Added an experimental `diff' package.
* src/guile/Makefile.am (dist_guilemodule_DATA): Added `differ.scm'. * src/guile/skribilo/package/Makefile.am (dist_guilemodule_DATA): Added `diff.scm'. git-archimport-id: lcourtes@laas.fr--2006-libre/skribilo--devo--1.2--patch-22
Diffstat (limited to 'src/guile')
-rw-r--r--src/guile/Makefile.am2
-rw-r--r--src/guile/differ.scm443
-rw-r--r--src/guile/skribilo/package/Makefile.am2
-rw-r--r--src/guile/skribilo/package/diff.scm304
4 files changed, 749 insertions, 2 deletions
diff --git a/src/guile/Makefile.am b/src/guile/Makefile.am
index e410a87..6a27133 100644
--- a/src/guile/Makefile.am
+++ b/src/guile/Makefile.am
@@ -1,5 +1,5 @@
SUBDIRS = skribilo
guilemoduledir = $(GUILE_SITE)
-dist_guilemodule_DATA = skribilo.scm
+dist_guilemodule_DATA = skribilo.scm differ.scm
EXTRA_DIST = README
diff --git a/src/guile/differ.scm b/src/guile/differ.scm
new file mode 100644
index 0000000..f8ff18b
--- /dev/null
+++ b/src/guile/differ.scm
@@ -0,0 +1,443 @@
+;;; "differ.scm" O(NP) Sequence Comparison Algorithm.
+;;; Copyright (C) 2001, 2002, 2003, 2004 Aubrey Jaffer
+
+;;;
+;;; Taken from Slib 3a2 and adapated by Ludovic Courtès
+;;; <ludovic.courtes@laas.fr> to use Guile's native API (March 2007).
+;;;
+
+(define-module (differ)
+ :export (diff:longest-common-subsequence diff:edits
+ diff:edit-length))
+
+;Permission to copy this software, to modify it, to redistribute it,
+;to distribute modified versions, and to use it for any purpose is
+;granted, subject to the following restrictions and understandings.
+;
+;1. Any copy made of this software must include this copyright notice
+;in full.
+;
+;2. I have made no warranty or representation that the operation of
+;this software will be error-free, and I am under no obligation to
+;provide any services, by way of maintenance, update, or otherwise.
+;
+;3. In conjunction with products arising from the use of this
+;material, there shall be no use of my name in any advertising,
+;promotional, or sales literature without prior written consent in
+;each case.
+
+;;@noindent
+;;@code{diff:edit-length} implements the algorithm:
+;;
+;;@ifinfo
+;;@example
+;;S. Wu, E. Myers, U. Manber, and W. Miller,
+;; "An O(NP) Sequence Comparison Algorithm,"
+;; Information Processing Letters 35, 6 (1990), 317-323.
+;; @url{http://www.cs.arizona.edu/people/gene/PAPERS/np_diff.ps}
+;;@end example
+;;@end ifinfo
+;;@ifset html
+;;S. Wu, <A HREF="http://www.cs.arizona.edu/people/gene/vita.html">
+;;E. Myers,</A> U. Manber, and W. Miller,
+;;<A HREF="http://www.cs.arizona.edu/people/gene/PAPERS/np_diff.ps">
+;;"An O(NP) Sequence Comparison Algorithm"</A>,
+;;Information Processing Letters 35, 6 (1990), 317-323.
+;;@end ifset
+;;
+;;@noindent
+;;The values returned by @code{diff:edit-length} can be used to gauge
+;;the degree of match between two sequences.
+;;
+;;@noindent
+;;@code{diff:edits} and @code{diff:longest-common-subsequence} combine
+;;the algorithm with the divide-and-conquer method outlined in:
+;;
+;;@ifinfo
+;;@example
+;;E. Myers and W. Miller,
+;; "Optimal alignments in linear space",
+;; Computer Application in the Biosciences (CABIOS), 4(1):11-17, 1988.
+;; @url{http://www.cs.arizona.edu/people/gene/PAPERS/linear.ps}
+;;@end example
+;;@end ifinfo
+;;@ifset html
+;;<A HREF="http://www.cs.arizona.edu/people/gene/vita.html">
+;;E. Myers,</A> and W. Miller,
+;;<A HREF="http://www.cs.arizona.edu/people/gene/PAPERS/linear.ps">
+;;"Optimal alignments in linear space"</A>,
+;;Computer Application in the Biosciences (CABIOS), 4(1):11-17, 1988.
+;;@end ifset
+;;
+;;@noindent
+;;If the items being sequenced are text lines, then the computed
+;;edit-list is equivalent to the output of the @dfn{diff} utility
+;;program. If the items being sequenced are words, then it is like the
+;;lesser known @dfn{spiff} program.
+
+
+;;; p-lim is half the number of gratuitous edits for strings of given
+;;; lengths.
+;;; When passed #f CC, fp:compare returns edit-distance if successful;
+;;; #f otherwise (p > p-lim). When passed CC, fp:compare returns #f.
+(define (fp:compare fp fpoff CC A M B N p-lim)
+ (define Delta (- N M))
+ ;;(if (negative? Delta) (slib:error 'fp:compare (fp:subarray A 0 M) '> (fp:subarray B 0 N)))
+ ;;(set! compares (+ 1 compares)) ;(print 'fp:compare M N p-lim)
+ (let loop ((p 0))
+ (do ((k (- p) (+ 1 k)))
+ ((>= k Delta))
+ (fp:run fp fpoff k A M B N CC p))
+ (do ((k (+ Delta p) (+ -1 k)))
+ ((<= k Delta))
+ (fp:run fp fpoff k A M B N CC p))
+ (let ((fpval (fp:run fp fpoff Delta A M B N CC p)))
+ ;; At this point, the cost to (fpval-Delta, fpval) is Delta + 2*p
+ (cond ((and (not CC) (<= N fpval)) (+ Delta (* 2 p)))
+ ((and (not (negative? p-lim)) (>= p p-lim)) #f)
+ (else (loop (+ 1 p)))))))
+
+;;; Traces runs of matches until they end; then set fp[k]=y.
+;;; If CC is supplied, set each CC[y] = min(CC[y], cost) for run.
+;;; Returns furthest y reached.
+(define (fp:run fp fpoff k A M B N CC p)
+ (define cost (+ k p p))
+ (let snloop ((y (max (+ (array-ref fp (+ -1 k fpoff)) 1)
+ (array-ref fp (+ 1 k fpoff)))))
+ (define x (- y k))
+ (and CC (<= y N)
+ (let ((xcst (- M x)))
+ (cond ((negative? xcst))
+ (else (array-set! CC
+ (min (+ xcst cost) (array-ref CC y))
+ y)))))
+ ;;(set! tick (+ 1 tick))
+ (cond ((and (< x M) (< y N)
+ (eqv? (array-ref A x) (array-ref B y)))
+ (snloop (+ 1 y)))
+ (else (array-set! fp y (+ fpoff k))
+ y))))
+
+;;; Check that only 1 and -1 steps between adjacent CC entries.
+;;(define (fp:step-check A M B N CC)
+;; (do ((cdx (+ -1 N) (+ -1 cdx)))
+;; ((negative? cdx))
+;; (case (- (array-ref CC cdx) (array-ref CC (+ 1 cdx)))
+;; ((1 -1) #t)
+;; (else (cond ((> 30 (car (array-dimensions CC)))
+;; (display "A: ") (print A)
+;; (display "B: ") (print B)))
+;; (slib:warn
+;; "CC" (append (list (max 0 (+ -5 cdx)) ': (min (+ 1 N) (+ 5 cdx))
+;; 'of)
+;; (array-dimensions CC))
+;; (fp:subarray CC (max 0 (+ -5 cdx)) (min (+ 1 N) (+ 5 cdx))))))))
+
+;;; Correct cost jumps left by fp:compare [which visits only a few (x,y)].
+;;(define (smooth-costs CC N)
+;; (do ((cdx (+ -1 N) (+ -1 cdx))) ; smooth from end
+;; ((negative? cdx))
+;; (array-set! CC (min (array-ref CC cdx) (+ 1 (array-ref CC (+ 1 cdx))))
+;; cdx))
+;; (do ((cdx 1 (+ 1 cdx))) ; smooth toward end
+;; ((> cdx N))
+;; (array-set! CC (min (array-ref CC cdx) (+ 1 (array-ref CC (+ -1 cdx))))
+;; cdx))
+;; CC)
+
+(define (diff:mid-split N RR CC cost)
+ ;; RR is not longer than CC. So do for each element of RR.
+ (let loop ((cdx (+ 1 (quotient N 2)))
+ (rdx (quotient N 2)))
+ ;;(if (negative? rdx) (slib:error 'negative? 'rdx))
+ (cond ((eqv? cost (+ (array-ref CC rdx) (array-ref RR (- N rdx)))) rdx)
+ ((eqv? cost (+ (array-ref CC cdx) (array-ref RR (- N cdx)))) cdx)
+ (else (loop (+ 1 cdx) (+ -1 rdx))))))
+
+;;; Return 0-based shared array.
+;;; Reverse RA if END < START.
+(define (fp:subarray RA start end)
+ (define n-len (abs (- end start)))
+ (if (< end start)
+ (make-shared-array RA (lambda (idx) (list (+ -1 (- start idx)))) n-len)
+ (make-shared-array RA (lambda (idx) (list (+ start idx))) n-len)))
+
+(define (fp:init! fp fpoff fill mindx maxdx)
+ (define mlim (+ fpoff mindx))
+ (do ((idx (+ fpoff maxdx) (+ -1 idx)))
+ ((< idx mlim))
+ (array-set! fp fill idx)))
+
+;;; Split A[start-a..end-a] (shorter array) into smaller and smaller chunks.
+;;; EDX is index into EDITS.
+;;; EPO is insert/delete polarity (+1 or -1)
+(define (diff:divide-and-conquer fp fpoff CCRR A start-a end-a B start-b end-b edits edx epo p-lim)
+ (define mid-a (quotient (+ start-a end-a) 2))
+ (define len-b (- end-b start-b))
+ (define len-a (- end-a start-a))
+ (let ((tcst (+ p-lim p-lim (- len-b len-a))))
+ (define CC (fp:subarray CCRR 0 (+ len-b 1)))
+ (define RR (fp:subarray CCRR (+ len-b 1) (* 2 (+ len-b 1))))
+ (define M2 (- end-a mid-a))
+ (define M1 (- mid-a start-a))
+ (fp:init! CC 0 (+ len-a len-b) 0 len-b)
+ (fp:init! fp fpoff -1 (- (+ 1 p-lim)) (+ 1 p-lim (- len-b M1)))
+ (fp:compare fp fpoff CC
+ (fp:subarray A start-a mid-a) M1
+ (fp:subarray B start-b end-b) len-b
+ (min p-lim len-a))
+ (fp:init! RR 0 (+ len-a len-b) 0 len-b)
+ (fp:init! fp fpoff -1 (- (+ 1 p-lim)) (+ 1 p-lim (- len-b M2)))
+ (fp:compare fp fpoff RR
+ (fp:subarray A end-a mid-a) M2
+ (fp:subarray B end-b start-b) len-b
+ (min p-lim len-a))
+ ;;(smooth-costs CC len-b) (smooth-costs RR len-b)
+ (let ((b-splt (diff:mid-split len-b RR CC tcst)))
+ (define est-c (array-ref CC b-splt))
+ (define est-r (array-ref RR (- len-b b-splt)))
+ ;;(set! splts (cons (/ b-splt (max .1 len-b)) splts))
+ ;;(display "A: ") (array-for-each display (fp:subarray A start-a mid-a)) (display " + ") (array-for-each display (fp:subarray A mid-a end-a)) (newline)
+ ;;(display "B: ") (array-for-each display (fp:subarray B start-b end-b)) (newline)
+ ;;(print 'cc cc) (print 'rr (fp:subarray RR (+ 1 len-b) 0))
+ ;;(print (make-string (+ 7 (* 2 b-splt)) #\-) '^ (list b-splt))
+ (check-cost! 'CC est-c
+ (diff2et fp fpoff CCRR
+ A start-a mid-a
+ B start-b (+ start-b b-splt)
+ edits edx epo
+ (quotient (- est-c (- b-splt (- mid-a start-a)))
+ 2)))
+ (check-cost! 'RR est-r
+ (diff2et fp fpoff CCRR
+ A mid-a end-a
+ B (+ start-b b-splt) end-b
+ edits (+ est-c edx) epo
+ (quotient (- est-r (- (- len-b b-splt)
+ (- end-a mid-a)))
+ 2)))
+ (+ est-c est-r))))
+
+;;; Trim; then diff sub-arrays; either one longer. Returns edit-length
+(define (diff2et fp fpoff CCRR A start-a end-a B start-b end-b edits edx epo p-lim)
+ ;; (if (< (- end-a start-a) p-lim) (slib:warn 'diff2et 'len-a (- end-a start-a) 'len-b (- end-b start-b) 'p-lim p-lim))
+ (do ((bdx (+ -1 end-b) (+ -1 bdx))
+ (adx (+ -1 end-a) (+ -1 adx)))
+ ((not (and (<= start-b bdx)
+ (<= start-a adx)
+ (eqv? (array-ref A adx) (array-ref B bdx))))
+ (do ((bsx start-b (+ 1 bsx))
+ (asx start-a (+ 1 asx)))
+ ((not (and (< bsx bdx)
+ (< asx adx)
+ (eqv? (array-ref A asx) (array-ref B bsx))))
+ ;;(print 'trim-et (- asx start-a) '+ (- end-a adx))
+ (let ((delta (- (- bdx bsx) (- adx asx))))
+ (if (negative? delta)
+ (diff2ez fp fpoff CCRR B bsx (+ 1 bdx) A asx (+ 1 adx)
+ edits edx (- epo) (+ delta p-lim))
+ (diff2ez fp fpoff CCRR A asx (+ 1 adx) B bsx (+ 1 bdx)
+ edits edx epo p-lim))))
+ ;;(set! tick (+ 1 tick))
+ ))
+ ;;(set! tick (+ 1 tick))
+ ))
+
+;;; Diff sub-arrays, A not longer than B. Returns edit-length
+(define (diff2ez fp fpoff CCRR A start-a end-a B start-b end-b edits edx epo p-lim)
+ (define len-a (- end-a start-a))
+ (define len-b (- end-b start-b))
+ ;;(if (> len-a len-b) (slib:error 'diff2ez len-a '> len-b))
+ (cond ((zero? p-lim) ; B inserts only
+ (if (= len-b len-a)
+ 0 ; A = B; no edits
+ (let loop ((adx start-a)
+ (bdx start-b)
+ (edx edx))
+ (cond ((>= bdx end-b) (- len-b len-a))
+ ((>= adx end-a)
+ (do ((idx bdx (+ 1 idx))
+ (edx edx (+ 1 edx)))
+ ((>= idx end-b) (- len-b len-a))
+ (array-set! edits (* epo (+ 1 idx)) edx)))
+ ((eqv? (array-ref A adx) (array-ref B bdx))
+ ;;(set! tick (+ 1 tick))
+ (loop (+ 1 adx) (+ 1 bdx) edx))
+ (else (array-set! edits (* epo (+ 1 bdx)) edx)
+ ;;(set! tick (+ 1 tick))
+ (loop adx (+ 1 bdx) (+ 1 edx)))))))
+ ((<= len-a p-lim) ; delete all A; insert all B
+ ;;(if (< len-a p-lim) (slib:error 'diff2ez len-a len-b 'p-lim p-lim))
+ (do ((idx start-a (+ 1 idx))
+ (jdx start-b (+ 1 jdx)))
+ ((and (>= idx end-a) (>= jdx end-b)) (+ len-a len-b))
+ (cond ((< jdx end-b)
+ (array-set! edits (* epo (+ 1 jdx)) edx)
+ (set! edx (+ 1 edx))))
+ (cond ((< idx end-a)
+ (array-set! edits (* epo (- -1 idx)) edx)
+ (set! edx (+ 1 edx))))))
+ (else (diff:divide-and-conquer
+ fp fpoff CCRR A start-a end-a B start-b end-b
+ edits edx epo p-lim))))
+
+(define (check-cost! name est cost)
+ (if (not (eqv? est cost))
+ (slib:warn name "cost check failed" est '!= cost)))
+
+;;;; Routines interfacing API layer to algorithms.
+
+(define (diff:invert-edits! edits)
+ (define cost (car (array-dimensions edits)))
+ (do ((idx (+ -1 cost) (+ -1 idx)))
+ ((negative? idx))
+ (array-set! edits (- (array-ref edits idx)) idx)))
+
+;;; len-a < len-b
+(define (edits2lcs! lcs edits A)
+ (define cost (car (array-dimensions edits)))
+ (define len-a (car (array-dimensions A)))
+ (let loop ((edx 0)
+ (sdx 0)
+ (adx 0))
+ (let ((edit (if (< edx cost) (array-ref edits edx) 0)))
+ (cond ((>= adx len-a))
+ ((positive? edit)
+ (loop (+ 1 edx) sdx adx))
+ ((zero? edit)
+ (array-set! lcs (array-ref A adx) sdx)
+ (loop edx (+ 1 sdx) (+ 1 adx)))
+ ((>= adx (- -1 edit))
+ (loop (+ 1 edx) sdx (+ 1 adx)))
+ (else
+ (array-set! lcs (array-ref A adx) sdx)
+ (loop edx (+ 1 sdx) (+ 1 adx)))))))
+
+;; A not longer than B (M <= N)
+(define (diff2edits! edits fp CCRR A B)
+ (define N (car (array-dimensions B)))
+ (define M (car (array-dimensions A)))
+ (define est (car (array-dimensions edits)))
+ (let ((p-lim (quotient (- est (- N M)) 2)))
+ (check-cost! 'diff2edits!
+ est
+ (diff2et fp (+ 1 p-lim)
+ CCRR A 0 M B 0 N edits 0 1 p-lim))))
+
+;; A not longer than B (M <= N)
+(define (diff2editlen fp A B p-lim)
+ (define N (car (array-dimensions B)))
+ (define M (car (array-dimensions A)))
+ (let ((maxdx (if (negative? p-lim) (+ 1 N) (+ 1 p-lim (- N M))))
+ (mindx (if (negative? p-lim) (- (+ 1 M)) (- (+ 1 p-lim)))))
+ (fp:init! fp (- mindx) -1 mindx maxdx)
+ (fp:compare fp (- mindx) #f A M B N p-lim)))
+
+
+;;;
+;;; Public API.
+;;;
+
+;;@args array1 array2 p-lim
+;;@args array1 array2
+;;@1 and @2 are one-dimensional arrays.
+;;
+;;The non-negative integer @3, if provided, is maximum number of
+;;deletions of the shorter sequence to allow. @0 will return @code{#f}
+;;if more deletions would be necessary.
+;;
+;;@0 returns a one-dimensional array of length @code{(quotient (- (+
+;;len1 len2) (diff:edit-length @1 @2)) 2)} holding the longest sequence
+;;common to both @var{array}s.
+(define (diff:longest-common-subsequence A B . p-lim)
+ (define M (car (array-dimensions A)))
+ (define N (car (array-dimensions B)))
+ (set! p-lim (if (null? p-lim) -1 (car p-lim)))
+ (let ((edits (if (< N M)
+ (diff:edits B A p-lim)
+ (diff:edits A B p-lim))))
+ (and edits
+ (let* ((cost (car (array-dimensions edits)))
+ (lcs (make-typed-array (array-type A) *unspecified*
+ (/ (- (+ N M) cost) 2))))
+ (edits2lcs! lcs edits (if (< N M) B A))
+ lcs))))
+
+;;@args array1 array2 p-lim
+;;@args array1 array2
+;;@1 and @2 are one-dimensional arrays.
+;;
+;;The non-negative integer @3, if provided, is maximum number of
+;;deletions of the shorter sequence to allow. @0 will return @code{#f}
+;;if more deletions would be necessary.
+;;
+;;@0 returns a vector of length @code{(diff:edit-length @1 @2)} composed
+;;of a shortest sequence of edits transformaing @1 to @2.
+;;
+;;Each edit is an integer:
+;;@table @asis
+;;@item @var{k} > 0
+;;Inserts @code{(array-ref @1 (+ -1 @var{j}))} into the sequence.
+;;@item @var{k} < 0
+;;Deletes @code{(array-ref @2 (- -1 @var{k}))} from the sequence.
+;;@end table
+(define (diff:edits A B . p-lim)
+ (define M (car (array-dimensions A)))
+ (define N (car (array-dimensions B)))
+ (set! p-lim (if (null? p-lim) -1 (car p-lim)))
+ (let ((fp (make-typed-array 's32 0
+ (if (negative? p-lim)
+ (+ 3 M N)
+ (+ 3 (abs (- N M)) p-lim p-lim)))))
+ (define est (if (< N M)
+ (diff2editlen fp B A p-lim)
+ (diff2editlen fp A B p-lim)))
+ (and est
+ (let ((edits (make-typed-array 's32 0 est))
+ (CCRR (make-typed-array 's32 0 (* 2 (+ (max M N) 1)))))
+ (cond ((< N M)
+ (diff2edits! edits fp CCRR B A)
+ (diff:invert-edits! edits))
+ (else
+ (diff2edits! edits fp CCRR A B)))
+ ;;(diff:order-edits! edits est)
+ edits))))
+
+;;@args array1 array2 p-lim
+;;@args array1 array2
+;;@1 and @2 are one-dimensional arrays.
+;;
+;;The non-negative integer @3, if provided, is maximum number of
+;;deletions of the shorter sequence to allow. @0 will return @code{#f}
+;;if more deletions would be necessary.
+;;
+;;@0 returns the length of the shortest sequence of edits transformaing
+;;@1 to @2.
+(define (diff:edit-length A B . p-lim)
+ (define M (car (array-dimensions A)))
+ (define N (car (array-dimensions B)))
+ (set! p-lim (if (null? p-lim) -1 (car p-lim)))
+ (let ((fp (make-typed-array 's32 0
+ (if (negative? p-lim)
+ (+ 3 M N)
+ (+ 3 (abs (- N M)) p-lim p-lim)))))
+ (if (< N M)
+ (diff2editlen fp B A p-lim)
+ (diff2editlen fp A B p-lim))))
+
+;;@example
+;;(diff:longest-common-subsequence "fghiejcklm" "fgehijkpqrlm")
+;;@result{} "fghijklm"
+;;
+;;(diff:edit-length "fghiejcklm" "fgehijkpqrlm")
+;;@result{} 6
+;;
+;;(diff:edits "fghiejcklm" "fgehijkpqrlm")
+;;@result{} #A:fixZ32b(3 -5 -7 8 9 10)
+;; ; e c h p q r
+;;@end example
+
+;;(trace-all "/home/jaffer/slib/differ.scm")(set! *qp-width* 333)(untrace fp:run fp:subarray)
+
+
+;;;arch-tag: 8e80eb1d-fb11-4872-895a-8adcee26580d
diff --git a/src/guile/skribilo/package/Makefile.am b/src/guile/skribilo/package/Makefile.am
index 693f088..ac7c18e 100644
--- a/src/guile/skribilo/package/Makefile.am
+++ b/src/guile/skribilo/package/Makefile.am
@@ -2,6 +2,6 @@ guilemoduledir = $(GUILE_SITE)/skribilo/package
dist_guilemodule_DATA = acmproc.scm french.scm jfp.scm letter.scm \
lncs.scm scribe.scm sigplan.scm skribe.scm \
slide.scm web-article.scm web-book.scm \
- eq.scm pie.scm base.scm
+ eq.scm pie.scm base.scm diff.scm
SUBDIRS = slide eq pie
diff --git a/src/guile/skribilo/package/diff.scm b/src/guile/skribilo/package/diff.scm
new file mode 100644
index 0000000..f42f7f4
--- /dev/null
+++ b/src/guile/skribilo/package/diff.scm
@@ -0,0 +1,304 @@
+;;; diff.scm -- A document difference highlighting package.
+;;;
+;;; Copyright 2007 Ludovic Courtès <ludovic.courtes@laas.fr>
+;;;
+;;;
+;;; 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.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with this program; if not, write to the Free Software
+;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+;;; USA.
+
+(define-module (skribilo package diff)
+ :use-module (differ)
+ :use-module (srfi srfi-1)
+ :use-module (srfi srfi-39)
+ :use-module (ice-9 optargs)
+
+ :use-module (skribilo ast)
+ :use-module (skribilo lib)
+ :autoload (skribilo reader) (*document-reader*)
+ :autoload (skribilo engine) (*current-engine*)
+ :autoload (skribilo module) (make-run-time-module)
+ :autoload (skribilo resolve) (resolve!)
+ :autoload (skribilo evaluator) (evaluate-ast-from-port)
+ :autoload (skribilo biblio) (*bib-table* make-bib-table)
+ :use-module (skribilo package base)
+ :use-module (skribilo utils syntax)
+
+ :export (make-diff-document-from-files))
+
+(fluid-set! current-reader %skribilo-module-reader)
+
+;;; Author: Ludovic Courtès
+;;;
+;;; Commentary:
+;;;
+;;; This package provides facilities to automatically produce documents where
+;;; changes from a previous version of the document are highlighted.
+;;;
+;;; Warning: This is very experimental at this stage!
+;;;
+;;; Code:
+
+
+
+;;;
+;;; Markup.
+;;;
+
+(define-markup (deletion :rest args)
+ (color :fg "red" "[deletion]"))
+
+(define-markup (insertion :rest args)
+ (color :fg "green" args))
+
+(define-markup (unchanged :rest args)
+ args)
+
+
+;;;
+;;; Helpers for string diffs.
+;;;
+
+(define (coalesce-edits edits)
+ ;; Coalesce EDITS (an array of edits as returned by `diff:edits') into a
+ ;; list of contiguous changes, each change being denoted by `(CHANGE-KIND
+ ;; START END)' where CHANGE-KIND is one of `deletion', `insertion' or
+ ;; `replacement'.
+ (define (do-coalesce edit-kind edit result)
+ (cond ((null? result)
+ `((,edit-kind ,edit ,edit)))
+ ((eq? (caar result) edit-kind)
+ (let ((start (cadr (car result)))
+ (end (caddr (car result))))
+ (if (= edit (+ end 1))
+ (cons `(,edit-kind ,start ,edit)
+ (cdr result))
+ (cons `(,edit-kind ,edit ,edit)
+ result))))
+ (else
+ (let ((start (cadr (car result)))
+ (end (caddr (car result))))
+ (if (and (= start end edit)
+ (not (eq? (caar result) 'replacement)))
+ (do-coalesce 'replacement edit (cdr result))
+ (cons `(,edit-kind ,edit ,edit)
+ result))))))
+
+ (reverse! (fold (lambda (edit result)
+ (if (negative? edit)
+ (let ((edit (- -1 edit)))
+ (do-coalesce 'deletion edit result))
+ (let ((edit (- edit 1)))
+ (do-coalesce 'insertion edit result))))
+ '()
+ (array->list edits))))
+
+(define (add-unchanged edits str-len)
+ ;; Add information about unchanged regions to EDITS, a list returned by
+ ;; `coalesce-edits'. STR-LEN should be the length of the _target_ string,
+ ;; i.e., the second argument of `diff:edits'.
+ (define %nop '(unchanged 0 0))
+ (define (strip-nop result)
+ (if (equal? (car result) %nop)
+ (cdr result)
+ result))
+
+ (let loop ((edits edits)
+ (result (list (list 'unchanged 0 0)))
+ (str-pos 0))
+ (if (null? edits)
+ (strip-nop
+ (reverse! (if (< str-pos (- str-len 1))
+ (cons (list 'unchanged str-pos (- str-len 1))
+ result)
+ result)))
+ (let* ((change (car edits))
+ (kind (car change))
+ (start (cadr change))
+ (end (caddr change))
+
+ (prev-unchanged? (eq? (caar result) 'unchanged))
+ (prev-start (cadr (car result)))
+ (prev-end (caddr (car result))))
+
+ (loop (cdr edits)
+ (if (memq kind '(insertion replacement))
+ (if (> start (+ 1 prev-end))
+ (if prev-unchanged?
+ (cons* change
+ `(unchanged ,prev-start
+ ,(- start 1))
+ (cdr result))
+ (cons* change
+ `(unchanged ,(+ 1 prev-end)
+ ,(- start 1))
+ result))
+ (cons change result))
+ (cons change result))
+ (+ end 1))))))
+
+(define (string-diff-sequences str1 str2)
+ ;; Return a "diff sequence" between STR1 and STR2. The diff sequence is
+ ;; alist of 3-element list whose car represent a diff type (a symbol,
+ ;; either `unchanged', `replacement', `insertion', or `deletion') and two
+ ;; integers denoting where the change took place. These two integers are
+ ;; an indices in STR1 in the case of `deletion', indices in STR2 otherwise.
+ (add-unchanged (coalesce-edits (diff:edits str1 str2))
+ (string-length str2)))
+
+
+
+;;;
+;;; AST diffing.
+;;;
+
+(define %undiffable-markups
+ ;; List of markups to not diff.
+ '(ref url-ref bib-ref bib-ref+ line-ref unref
+ figref ;; non-standard
+ mark
+ image symbol lout-illustration
+ &the-bibliography
+ toc
+ index &index-entry &the-index &the-index-header))
+
+(define (make-diff-document ast1 ast2)
+ ;; Return a document based on AST2 that highlights differences between AST1
+ ;; and AST2, enclosing unchanged parts in `unchanged' markups, etc.
+ (let loop ((ast1 ast1)
+ (ast2 ast2))
+ ;;(format (current-error-port) "diff: ~a ~a~%" ast1 ast2)
+ (cond ((string? ast2)
+ (if (string? ast1)
+ (reverse!
+ (fold (lambda (edit result)
+ (let ((start (cadr edit))
+ (end (+ 1 (caddr edit))))
+ (cons (case (car edit)
+ ((insertion)
+ (insertion (substring ast2 start end)))
+ ((deletion)
+ (deletion (substring ast1 start end)))
+ ((replacement)
+ (replacement (substring ast2 start end)))
+ ((unchanged)
+ (unchanged (substring ast2 start end))))
+ result)))
+ '()
+ (string-diff-sequences ast1 ast2)))
+ (insertion ast2)))
+
+ ((document? ast2)
+ (let ((ident (or (markup-ident ast2)
+ (ast->string (markup-option ast2 :title))
+ (symbol->string (gensym "document"))))
+ (opts (markup-options ast2))
+ (class (markup-class ast2))
+ (body (markup-body ast2)))
+ (new document
+ (markup 'document)
+ (ident ident)
+ (class class)
+ (options opts)
+ (body (loop (if (markup? ast1)
+ (markup-body ast1)
+ ast1)
+ body))
+ (env (list (list 'chapter-counter 0) (list 'chapter-env '())
+ (list 'section-counter 0) (list 'section-env '())
+ (list 'footnote-counter 0)
+ (list 'footnote-env '())
+ (list 'figure-counter 0)
+ (list 'figure-env '()))))))
+
+ ((container? ast2)
+ (let ((kind (markup-markup ast2))
+ (ident (markup-ident ast2))
+ (opts (markup-options ast2))
+ (class (markup-class ast2))
+ (body (markup-body ast2)))
+ (new container
+ (markup kind)
+ (ident ident)
+ (class class)
+ (options opts)
+ (body (loop (if (markup? ast1)
+ (markup-body ast1)
+ ast1)
+ body)))))
+
+ ((markup? ast2)
+ (let ((kind (markup-markup ast2))
+ (ident (markup-ident ast2))
+ (opts (markup-options ast2))
+ (class (markup-class ast2))
+ (body (markup-body ast2)))
+ (new markup
+ (markup kind)
+ (ident ident)
+ (class class)
+ (options opts)
+ (body (if (memq kind %undiffable-markups)
+ body
+ (loop (if (markup? ast1)
+ (markup-body ast1)
+ ast1)
+ body))))))
+
+ ((list? ast2)
+ (if (list? ast1)
+ (map loop ast1 ast2)
+ (map (lambda (x)
+ (loop ast1 x))
+ ast2)))
+
+ (else
+ (insertion ast2)))))
+
+
+
+;;;
+;;; Public API.
+;;;
+
+(define* (make-diff-document-from-files old-file new-file
+ :key (reader (*document-reader*))
+ (env '())
+ (engine (*current-engine*)))
+ ;; Return a document similar to NEW-FILE, where differences from OLD-FILE
+ ;; are highlighted.
+ (let ((ast1
+ (parameterize ((*bib-table* (make-bib-table 'doc-1)))
+ (evaluate-ast-from-port (open-input-file old-file)
+ :reader reader
+ :module (make-run-time-module))))
+ (~~ (skribe-message "diff: first document loaded"))
+ (ast2
+ (parameterize ((*bib-table* (make-bib-table 'doc-2)))
+ (evaluate-ast-from-port (open-input-file new-file)
+ :reader reader
+ :module (make-run-time-module))))
+ (%% (skribe-message "diff: second document loaded")))
+
+ (resolve! ast1 engine env)
+ (resolve! ast2 engine env)
+ (let ((diff (make-diff-document ast1 ast2)))
+ (format (current-error-port) "diff-doc: ~a ~a~%"
+ diff (document? diff))
+ diff)))
+
+
+;;; diff.scm ends here
+
+;;; arch-tag: 69ad10fa-5688-4835-8956-439e44e26847