Eskil

    set ch1 [open $::diff($top,leftFile) r]
    set ch2 [open $::diff($top,rightFile) r]
    set doingLine1 1
    set doingLine2 1
    set changeNo 0
    foreach change $::diff($top,changes) {
        foreach {start length type line1 n1 line2 n2} $change break
        lassign $change start length type line1 n1 line2 n2
        set data1 {}
        set data2 {}
        while {$doingLine1 < $line1} {
            gets $ch1 apa
            append data1 $apa\n
            incr doingLine1
        }