use warnings; use Devel::Trace::Subs qw(trace trace_dump); # injected by Devel::Trace::Subs use strict; three(5); sub three { trace() if $ENV{DTS_ENABLE}; # injected by Devel::Trace::Subs return two(shift); } sub two { trace() if $ENV{DTS_ENABLE}; # injected by Devel::Trace::Subs return one(_helper(shift)); } sub one { trace() if $ENV{DTS_ENABLE}; # injected by Devel::Trace::Subs my $num = calc(shift); display($num); } sub calc { trace() if $ENV{DTS_ENABLE}; # injected by Devel::Trace::Subs my $num = shift; return $num ** 3; } sub display { trace() if $ENV{DTS_ENABLE}; # injected by Devel::Trace::Subs my $num = shift; print "$num\n"; } sub _helper { trace() if $ENV{DTS_ENABLE}; # injected by Devel::Trace::Subs my $num = shift; return ++$num; }