Updated 2012-09-27 10:51:20 by LkpPo

Keith Vetter 2003-11-07 : There's been a recent hue and cry for "a good diffs module" (see There is a huge need for a diffs module!). Here's something I've been using for half a year or so.

You enter a wiki page number and it displays the revision history for that page. You then select any two entries, click a button and it will fetch those two revisions and run tkdiff on them (or if you prefer you can use ExamDiff [1]).

This works reasonably well but with two flaws: first, the information in the wiki history seems to be a day behind the wiki itself, and second, wiki pages often contain very long lines that don't have good diff behavior. WikiDiff handles this second problem in a very clever way by doing a word level diff.

KPV It seems these two flaws have been addressed. The first via an undocumented interface that lets you access the latest version; the second by the new version of tkdiff (4.0b1) that does inline comparisons.

KPV 2004-01-23: Added Recents window, a Tkhtml widget showing Wiki page 4--Recent changes. Clicking on any link will put its Wiki page number into the Wiki Page entry. Double clicking any link will fetch that page's history.

Keith, FYI, on Mac OS X the above needs font "courier 10" to be readable (with X11). Also note that this works fine with the tkdiff starkit on sdarchive. Great utility! -jcw

KPV 2007-06-12: I updated the code to use the new wiki history format.

LV Hi! I was wondering - I am seeing the error:
 diff failed:
 Warning: missing newline at end of file /tmp/wiki.10335.27
 Warning: missing newline at end of file /tmp/wiki.10335.28

when I select page 10335 and ask for a difference in the last two versions...

KPV This utility uses tkdiff for its diff, and that in turn uses diff, the many versions of which behave differently on missing newline handlng. I'm using cygwin diff v2.8.7 on windows without a problem. You could see if your diff takes a command line argument to ignore irrelevant whitespace.

Another alternative is to use a different visual diff program, such as Examdiff.

LV 2007 June 13 - anyone know what version of tkhtml this code is expecting? When I try to run it, I get the error:
 unknown option "-background"
    while executing
 "html .r.h -yscrollcommand {.r.v set} -background white -height 500"
    (procedure "Recents" line 10)
    invoked from within
    (file "/projects/xopsrc/bin/wikidiff.tcl" line 330)

LV looks like it is using Tkhtml 2. Anyone know how to update this so that it works for either version 2 or 3?

KPV Ugh. I might just throw away Tkhtml and use the rss feed directly.
 # Wiki History Diff.tcl -- diffs back versions of the tcl Wiki pages
 # by Keith Vetter
 # Revisions:
 # KPV Mar 11, 2003 - initial revision
 # KPV Nov 07, 2003 - some touch up work
 # KPV Nov 10, 2003 - added JCW's undocumented way of fetching latest version
 # KPV Jan 23, 2004 - added Recents window showing Wiki page 4
 # KPV Jun 12, 2007 - updated to use new history format

 package require Tk
 package require http
 set S(tkhtml) [expr {! [catch {package require Tkhtml 2}]}]

 set S(diffprog) tkdiff                          ;# Examdiff.exe works well too
 set S(title) "Wiki History Diff"
 set S(bg) "#9977cc"
 set S(pnum) "xx"                                ;# Page we want to compare
 set S(pnum2) ""                                 ;# Entry widget version of pnum
 set S(busy) 0
 set S(font) {courier 8}
 if {$tcl_platform(machine) == "Power Macintosh"} {
    set S(font) {courier 10}

 # Stupid temp directory
 set S(tmp) [pwd]
 if {[file isdirectory "c:/temp"]} { set S(tmp) "c:/temp"}
 if {[file isdirectory "/tmp"]} { set S(tmp) "/tmp"}
 catch {set S(tmp) $env(TRASH_FOLDER)}           ;# Macintosh(?)
 catch {set S(tmp) $env(TMPDIR)}
 catch {set S(tmp) $env(TMP)}
 catch {set S(tmp) $env(TEMP)}

 proc INFO {msg} {puts [set ::S(msg) $msg]}
 proc DoDisplay {} {
    global S

    wm title . "Wiki History Diff"
    wm protocol . WM_DELETE_WINDOW {Cleanup 1}
    wm geom . +10+10
    frame .bottom
    pack .bottom -side bottom -fill x

    button .recent -text "Show Recent Changes" -command Recents
    if {! $S(tkhtml)} { .recent config -state disabled}
    label .msg -textvariable S(msg)
    button .about -text About -command About
    pack .recent -in .bottom -side left -padx .1i
    pack .about -in .bottom -side right -padx .1i
    pack .msg -in .bottom -side bottom -fill x

    option add *Label.background $S(bg)
    option add *Label.foreground white
    option add *Button.background $S(bg)
    option add *Button.activeBackground $S(bg)
    option add *Button.foreground white
    option add *Button.activeForeground white

    frame .top -bg $S(bg) -relief groove -bd 2
    frame .topl -bg $S(bg)
    button .topl.wiki -text "Wiki Page " -command DoWikiPage -relief flat
    entry .topl.ewiki -textvariable S(pnum2) -relief sunken -width 6
    bind .topl.ewiki <Key-Return> [list .topl.wiki invoke]
    label .top.title -textvariable S(title) -fg magenta
    trace variable S(pnum2) w tracer

    set font [font actual [.top.title cget -font]]
    .top.title config -font "$font -weight bold -size 18"

    frame .topr -bg $S(bg)
    label .topr.l0 -text "Version "
    label .topr.e0 -textvar S(left) -width 5 -relief sunken
    label .topr.v -text " vs. "
    label .topr.l1 -text "Version "
    label .topr.e1 -textvar S(right) -width 5 -relief sunken
    label .topr.= -text " => "
    button .topr.diff -text "Run $S(diffprog)" -command RunTKDiff -bd 5

    pack .top -side top -fill x
    pack .topr -in .top -side right
    pack .topl -in .top -side left
    pack .top.title -side top -expand 1
    eval pack [winfo child .topl] -side left
    eval pack [winfo child .topr] -side left
    pack config .topl.wiki -padx {.1i .05i}
    pack config .topr.diff -padx {0 .1i}

    pack [frame .mid -bd 4 -relief ridge] -side top -fill both -expand 1
    foreach w {0 1} side {left right} {
        listbox .l$w -exportselection 0 -width 63 -activestyle none -bd 0 \
            -font {courier 8} -yscrollcommand [list .sb$w set] -height 20
        bind .l$w <<ListboxSelect>> [list ListboxSelect %W $side]
        bind .l$w <1> [list focus %W]
        scrollbar .sb$w -orient v -command [list .l$w yview]
    grid .l0 .sb0 .l1 .sb1 -in .mid -sticky news
    grid rowconfigure .mid 0 -weight 1
    grid columnconfigure .mid {0 2} -weight 1
    option clear
    bind all <Key-F2> {console show}
    bind all <Control-w> exit
    focus .topl.ewiki
 proc ListboxSelect {W side} {
    global S

    set row [$W curselection]
    set data [$W get $row]
    set S($side) [lindex [split [string trimleft $data] " "] 0]
 proc tracer {var1 var2 op} {
    global S

    if {$S(pnum2) == $S(pnum)} {
        .topl.ewiki config -bg [lindex [.topl.ewiki config -bg] 3]
        .topl.wiki config -relief flat
    } else {
        .topl.ewiki config -bg red
        .topl.wiki config -relief raised
 proc GetVersionInfo {} {
    global S

    .l0 delete 0 end
    .l1 delete 0 end
    set S(left) [set S(right) ""]

    set url "http://wiki.tcl.tk/_history/$S(pnum)"
    set token [::http::geturl $url]
    set data [::http::data $token] ; list
    ::http::cleanup $token

    set S(title) "No Wiki History"
    regexp -line {Change history of.*?>(.*?)</a>} $data => S(title)
    set S(title) "\"$S(title)\""

    foreach line [split $data "\n"] {
        if {! [string match "<tr><td*" $line]} continue
        regsub -all {</*?a.*?>} $line {} line
        set matches [regexp -all -inline {<td.*?>(.*?)</td>} $line]
        foreach {. vnum . vwhen . vwho} $matches break
        set txt [format " %3s   %-20s  %s" $vnum $vwho $vwhen]
        .l0 insert end $txt
        .l1 insert end $txt

    .l0 selection clear 0 end
    .l0 selection set 1
    .l0 selection anchor 1
    event generate .l0 <<ListboxSelect>>
    .l1 selection clear 0 end
    .l1 selection set 0
    .l1 selection anchor 0
    event generate .l1 <<ListboxSelect>>
 proc GetRevision {pnum ver} {
    set fname [file join $::S(tmp) "wiki.$pnum.$ver"]
    set fout [open $fname "w"]

    # http://wiki.tcl.tk/_revision/606.txt?V=156
    set url "http://wiki.tcl.tk/_revision/${pnum}.txt?V=$ver"
    set token [::http::geturl $url -channel $fout]
    puts $fout ""       ; # added by lv to handle missing newline
    close $fout
    ::http::cleanup $token

    return $fname
 proc RunTKDiff {} {
    global S

    if {$S(left) eq "" || $S(left) eq ""} return
    set f1 [GetRevision $S(pnum) $S(left)]
    set f2 [GetRevision $S(pnum) $S(right)]

    exec $S(diffprog) $f1 $f2 &
    set ::TMPFILES($f1) 1
    set ::TMPFILES($f2) 1
    after 2000                                  ;# Pause to let tkdiff start
 proc DoWikiPage {} {
    global S

    set S(busy) 1
    while {1} {
        after 10 Cleanup
        .topl.ewiki icursor end
        if {! [string is integer -strict $S(pnum2)]} break
        if {$S(pnum) == $S(pnum2)} break
        set S(pnum) $S(pnum2)
        set S(pnum2) $S(pnum2)
    set S(busy) 0
 proc Cleanup {{exit 0}} {
    global TMPFILES

    foreach fname [array names TMPFILES] {
        set n [catch {file delete $fname}]
        if {! $n} { unset TMPFILES($fname) }
    if {$exit} exit
 proc About {} {
    set msg "WikiDiff\nby Keith Vetter\nMarch 2003\n\n"
    append msg "Compares back revisions of a\nTcl'ers Wiki "
    append msg "page using tkdiff."
    tk_messageBox -title "About" -message $msg
 proc Recents {} {
    if {! $::S(tkhtml)} return
    destroy .r
    toplevel .r
    wm title .r "WIKI Recent Changes"
    wm transient .r .
    wm geom .r +10+470

    scrollbar .r.v -o v -command {.r.h yv}
    html .r.h -yscrollcommand {.r.v set} -background white -height 500
    bind .r.h.x <1> [list Click 1 %x %y]
    bind .r.h.x <Double-Button-1> [list Click 2 %x %y]
    bind .r.h.x <Button-3> [list 3Click %x %y]
    #bind .r.h <MouseWheel> [bind Text <MouseWheel>]

    pack .r.v -side right -fill y
    pack .r.h -side left -fill both -expand 1
 proc FillRecents {} {
    .r.h clear
    .r.h parse "<html><body><p>Downloading Recent Changes...</body></html>"
    #update idletask

    set url "http://wiki.tcl.tk/4"
    set url "http://wiki.tcl.tk/4"
    set n [catch {
        set token [::http::geturl $url]
    if {$n} {                                   ;# Error
        .r.h clear
        .r.h parse "<html><body><p>Error loading Recent Changes</body></html>"

    set data [::http::data $token] ; list
    ::http::cleanup $token

    .r.h clear
    .r.h config -base $url
    .r.h parse $data
    set ::data $data
    focus .r.h
 proc Click {cnt x y} {
    if {$::S(busy)} return
    set href [.r.h href $x $y]
    set ::href $href
    if {$href == ""} return
    if {$href == "{http://wiki.tcl.tk/4!}"} {
        if {$cnt == 2} FillRecents
    set ::href $href
    set n [regexp {/(\d+)\}?$} $href => pnum]
    if {! $n} return

    set ::S(pnum2) $pnum
    if {$cnt == 2} {
        .topl.wiki invoke
 proc 3Click {x y} {
    set href [.r.h href $x $y]
    if {$href == ""} return

    set n [catch {eval exec [auto_execok start] $href &} err]
 proc MouseWheelBind {} {
    # Taken from tip #171

    # Remove existing class MouseWheel bindings
    set mw_classes [list Text Listbox Table TreeCtrl]
    foreach class $mw_classes { bind $class <MouseWheel> {} }
    if {[tk windowingsystem] eq "x11"} {
        foreach class $mw_classes {
            bind $class <4> {}
            bind $class <5> {}
    proc ::tk::MouseWheel {wFired D X Y {dir y}} {
        # do not double-fire in case the class already has a binding
        if {[bind [winfo class $wFired] <MouseWheel>] ne ""} { return }
        # obtain the window the mouse is over
        set w [winfo containing $X $Y]
        # if we are outside the app, try and scroll the focus widget
        if {![winfo exists $w]} { catch {set w [focus]} }
        if {[winfo exists $w]} {
            # scrollbars have different call conventions
            if {[winfo class $w] eq "Scrollbar"} {
                catch {tk::ScrollByUnits $w \
                           [string index [$w cget -orient] 0] \
                           [expr {-($D/30)}]}
            } else {
                catch {$w ${dir}view scroll [expr {- ($D / 120) * 4}] units}
    bind all <MouseWheel> [list ::tk::MouseWheel %W %D %X %Y]
    bind all <Shift-MouseWheel> [list ::tk::MouseWheel %W %D %X %Y x]
    if {[tk windowingsystem] eq "x11"} {
        # Support for mousewheels on Linux/Unix commonly comes through
        # mapping the wheel to the extended buttons.
        bind all <4> [list ::tk::MouseWheel %W 120 %X %Y]
        bind all <5> [list ::tk::MouseWheel %W -120 %X %Y]
 set S(pnum2) [lindex $argv 0]
 .l0 insert end "Enter the number of a Wiki page to run diff on"