Eskil

set ::argv {}
set ::argc 0
package require Tk 8.4
catch {package require textSearch}

package require pstools
namespace import -force pstools::*
package require wcb

if {[catch {package require psballoon}]} {
    # Add a dummy if it does not exist.
    proc addBalloon {args} {}
} else {
    namespace import -force psballoon::addBalloon
}

set debug 0
set diffver "Version 2.0.5 2004-08-20"
set diffver "Version 2.0.5+ 2004-09-06"
set thisScript [file join [pwd] [info script]]
set thisDir [file dirname $thisScript]

# Follow any link
set tmplink $thisScript
while {[file type $tmplink] eq "link"} {
    set tmplink [file readlink $tmplink]

        for {set t 0} {$t < $d} {incr t} {
            $w insert end \n padding
        }
    }

    close $ch1
    close $ch2

    # We can turn off editing in the text windows after everything
    # is displayed.
    noEdit $top

    # Mark aligned lines
    if {[info exists ::diff($top,aligns)] && \
            [llength $::diff($top,aligns)] > 0} {
        foreach {align1 align2} $::diff($top,aligns) {
            set i [$::widgets($top,wLine1) search -regexp "\\m$align1\\M" 1.0]
            if {$i != ""} {

# Clear Editing state
proc resetEdit {top} {
    set ::diff($top,leftEdit) 0
    set ::diff($top,rightEdit) 0
    $top.mt.m entryconfigure "Edit Mode" -state normal

    $::widgets($top,wDiff1) tag configure padding -background {}
    $::widgets($top,wDiff2) tag configure padding -background {}
    resetEditW $::widgets($top,wDiff1)
    resetEditW $::widgets($top,wDiff2)
}

# Clear Editing state for a Text widget
proc resetEditW {w} {
    $w tag configure padding -background {}
    $w edit reset
    $w configure -undo 0

    set ::diff($w,allowChange) all
    $::widgets($top,wDiff1) edit reset
    $::widgets($top,wDiff1) configure -undo 0
    $::widgets($top,wDiff2) edit reset
    $::widgets($top,wDiff2) configure -undo 0
}

# Turn on editing on sides where it has not bew disallowed

    wcb::callback $w before insert {}
    wcb::callback $w before delete {}
}

# Do not allow any editing
proc noEdit {top} {
    noEditW $::widgets($top,wDiff1)
    noEditW $::widgets($top,wDiff2)
}

# Do not allow any editing in a Text widget
proc noEditW {w} {
    set ::diff($w,allowChange) none

    wcb::callback $w before insert [list TextInterceptInsert $w]
    wcb::callback $w before delete [list TextInterceptDelete $w]
}

proc TextInterceptInsert {w ow index str args} {
    if {$::diff($w,allowChange) eq "none"} {
        wcb::cancel
        return
    }
    if {$::diff($w,allowChange) eq "all"} return

    #wcb::cancel - Cancel a widget command 
    #wcb::replace - Replace arguments of a widget command with new ones

    # Disallow all new lines
    if {[string first "\n" $str] >= 0} {
        wcb::cancel
        return
    }
    foreach {tag str2} $args {
        if {[string first "\n" $str2] >= 0} {
            wcb::cancel
            return
        }
    }
}

proc TextInterceptDelete {w ow from {to {}}} {
    if {$::diff($w,allowChange) eq "none"} {
        wcb::cancel
        return
    }
    if {$::diff($w,allowChange) eq "all"} return

    if {$to eq ""} {
        set to $from+1char
    }
    set text [$ow get $from $to]
    # Disallow all new lines
    if {[string first "\n" $text] >= 0} {
        wcb::cancel
        return
    }
}

# Turn on editing for a Text widget
proc turnOnEdit {w} {
    $w tag configure padding -background \#f0f0f0
    $w configure -undo 1

    set ::diff($w,allowChange) line
}

# Turn on editing on sides where it has not been disallowed
proc allowEdit {top} {
    $top.mt.m entryconfigure "Edit Mode" -state disable
    if {$::diff($top,leftEdit) == 0} {
        set ::diff($top,leftEdit) 1
        $::widgets($top,wDiff1) tag configure padding -background \#f0f0f0
        $::widgets($top,wDiff1) configure -undo 1
        turnOnEdit $::widgets($top,wDiff1)
    }
    if {$::diff($top,rightEdit) == 0} {
        set ::diff($top,rightEdit) 1
        $::widgets($top,wDiff2) tag configure padding -background \#f0f0f0
        $::widgets($top,wDiff2) configure -undo 1
        turnOnEdit $::widgets($top,wDiff2)
    }
}

# Turn off editing on sides that do not correspond to a file
proc disallowEdit {top {side 0}} {
    if {$side == 0 || $side == 1} {
        set ::diff($top,leftEdit) -1

    }
}

# Start an undo block in a bunch of text widgets
proc startUndoBlock {args} {
    foreach w $args {
        $w configure -autoseparators 0
        # Open up editing for copy functions
        set ::diff($w,allowChange) all
    }
}

# End an undo block in a bunch of text widgets
proc endUndoBlock {args} {
    foreach w $args {
        $w configure -autoseparators 1
        $w edit separator
        set ::diff($w,allowChange) line
    }
}

# Copy a block
proc copyBlock {top from first last} {
    set to [expr {3 - $from}]

    set wfrom $::widgets($top,wDiff$from)
    set wto   $::widgets($top,wDiff$to)

    set tags ""