>perl -wMstrict -le
"sub tr  (&$) { $_[0]->($_[1]) }
 sub trx (&$) { $_[0]->($_[1]) }
 ;;
 $_ = 'foo';
 print 'A: ', tr{ print qq{tr match: $_[0]} }/foo/;
 print 'B: ', trx{ print qq{trx match: $_[0]} }/foo/;
"
A: 0
trx match: 1
B: 1