This is a study on replacing Tk's error dialog. The goal was to have something that better fits into [TclTalk]'s browsers design. The result is completely developed within TclTalk, for TclTalk.

 # Package tcltalkerrdlg
 #
 namespace eval ::tcltalk::errdlg {}

 variable ::tcltalk::errdlg::CALLERS
 variable ::tcltalk::errdlg::ERR
 variable ::tcltalk::errdlg::INFO
 variable ::tcltalk::errdlg::button

 proc ::tcltalk::errdlg::collectCallers {args} {
    # 2008-07-31|15:30:35|tb
    # Wrap up $::errorInfo to get a list of
    # procedure names and line numbers

    set lines [split "$::tcltalk::errdlg::INFO" \n]
    set pr ""
    set nr ""
    set result {}
    foreach ln $lines {
	set l [string trim $ln]

	if {[string range $l 1 4]=="proc"} {
	    regsub -all {\(} $l "" l
	    regsub -all {\)} $l "" l
	    regsub -all {\"} $l "" l
	    set pr [lindex [split $l " "] 1]
	    set nr [lindex [split $l " "] 3]
	    lappend result $pr
	    lappend result $nr
	}
    }
    return $result
 }

 proc ::tcltalk::errdlg::initializeNamespace {args} {
    # 2008-07-31|15:10:54|tb
    # Namespaces with dynamic variable content are
    # generally better initialized somewhere, also
    # other special initialization can be scripted
    # here, as TclTalk adds a call to this script
    # at the end of a packages source file.

    set ::tcltalk::errdlg::CALLERS {}
    set ::tcltalk::errdlg::ERR ""
    set ::tcltalk::errdlg::INFO ""
    set ::tcltalk::errdlg::button 0

    if {[info proc ::bgerror*] == "::bgerror"} {
	rename ::bgerror ::_bgerror
    }

    proc ::bgerror {err} {
	::tcltalk::errdlg::open $err
    }

 }

 proc ::tcltalk::errdlg::open {args} {
    # 2008-07-31|17:41:24|tb
    # This shows the error dialog, to be used as a replacement
    # for the source version of ::bgerror

    variable button
    set ::tcltalk::errdlg::INFO $::errorInfo
    set ::tcltalk::errdlg::ERR "Error: [lindex [split $::tcltalk::errdlg::INFO \n] 0]"
    set ::tcltalk::errdlg::CALLERS [::tcltalk::errdlg::collectCallers]

    catch {destroy .errDlg}
    set w [toplevel .errDlg]
    wm title $w "Application Error"

    set lblfont {Times 12 bold italic}
    pack [frame $w.labels -relief flat -borderwidth 2] -side top -fill x
    pack [canvas $w.labels.bitmap -width 32 -height 32 -highlightthickness 0] -side left
    $w.labels.bitmap create oval 0 0 31 31 -fill red -outline black
    $w.labels.bitmap create line 9 9 23 23 -fill white -width 4
    $w.labels.bitmap create line 9 23 23 9 -fill white -width 4
    pack [label $w.labels.info -wrap 600 -textvar ::tcltalk::errdlg::ERR -font $lblfont -foreground red -anchor w] -side left -fill x

    pack [frame $w.procs -relief flat -borderwidth 2] -side top -fill x
    pack [listbox $w.procs.lb -yscroll [list $w.procs.sb set] -height 4] -side left -fill both -expand true
    bind $w.procs.lb <<ListboxSelect>> [list ::tcltalk::errdlg::selectProcedure $w.procs.lb]
    pack [scrollbar $w.procs.sb -orient vertical -command [list $w.procs.lb yview]] -side right -fill y

    pack [frame $w.code -relief flat -borderwidth 2] -side top -fill both -expand true
    pack [::workspace $w.code.ws -width 64 -height 16 -yscroll [list $w.code.sb set]] -side left -fill both -expand true
    pack [scrollbar $w.code.sb -orient vertical -command [list $w.code.ws yview]] -side right -fill y

    pack [frame $w.buttons -relief flat -borderwidth 2] -side bottom -fill x
    set buttons [list ok Ok dismiss "Skip Messages"]
    set i 0
    foreach {name caption} $buttons {
	pack [button $w.buttons.$name -text $caption -default normal -command [namespace code [list set button $i]]] -side left
	incr i
    }
    $w.buttons.ok configure -default active

    foreach {p l} $::tcltalk::errdlg::CALLERS {
	$w.procs.lb insert end $p
    }

    ::tk::SetFocusGrab $w $w.buttons.ok

    vwait [namespace which -variable button]
    set copy $button; # Save a copy...

    ::tk::RestoreFocusGrab $w $w.buttons.ok destroy

    if {$copy == 1} {
	return -code break
    }
 }

 proc ::tcltalk::errdlg::selectProcedure {w} {
    # 2008-07-31|15:53:44|tb
    # This event handler is bound to <<ListboxSelect>>
    # on the error dialogs listbox.

    if {[winfo exists $w]} {
    set ndx [lindex [$w curselection] 0]
	if {"$ndx" != ""} {
	    set p [$w get $ndx]
	    set t [winfo toplevel $w]
	    set ws $t.code.ws
	    $ws delete 1.0 end
	    $ws insert end [::tcltalk::errdlg::see $p]
	    $ws.t edit modified 0
	    array set linenos $::tcltalk::errdlg::CALLERS
	    $ws.t see $linenos($p).0
	    $ws.t tag add errln $linenos($p).0 "$linenos($p).0 lineend"
	    $ws.t tag configure errln -background [lindex [$w configure -selectbackground] end]
	    $ws.t tag configure errln -foreground white
	}
    }
 }

 proc ::tcltalk::errdlg::see {cmd} {
    # 2008-08-01|00:00:40|tb
    set result "proc $cmd \{[info args $cmd]\} \{"
    append result [info body $cmd]
    append result "\}"
    return [string map {\t "    "} $result]
 }

 # Initialization
 ::tcltalk::errdlg::initializeNamespace

 package provide tcltalkerrdlg 0.1

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%| Category Development |%
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