[Xotcl] XOTcl-copy and trace

Gustaf Neumann neumann at wu-wien.ac.at
Fri Jan 4 13:56:31 CET 2008

Dear Florian,

tcl var-traces and copy/move operations is a hairy issue.
You are right, the the current behavior on the issue
is a bug. I can't currently look into the details (i am on vacation
in a small place in the alps until Jan 6), but my guess is that
the behavior was introduced by the changes due to

Use the following fix in the meantime, until i have
more time to look into the details (insert this code before
the first copy).

best regards
-gustaf neumann

Class PreserveVarTraces
PreserveVarTraces instproc copy {obj dest} {
  set traces ""
  foreach v [$obj info vars] {
    set t [$obj trace info variable $v]
    if {$t ne ""} {
      foreach ops $t {
    foreach {op cmd} $ops break
    append traces [list $obj trace add variable $v $op $cmd] "\n"
  set r [next]
  eval $traces
  return $r
::xotcl::Object::CopyHandler instmixin add PreserveVarTraces

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