From The RT System itself

...................
Because the transliteration table is built at compile time,
neither the SEARCHLIST nor the REPLACEMENTLIST are subjected to
double quote interpolation. That means that if you want to use
variables, you must use an eval()​:

  eval "tr/$oldlist/$newlist/";
  die $@​ if $@​;

  eval "tr/$oldlist/$newlist/, 1" or die $@​;
...................

Why don't invent a special modifier for such case? A modifier 'e' seems very
suitable. As well as modifier 'o' to compile once.

Good luck,
Vadim.

@iabyn - Status changed from 'stalled' to 'resolved'