my $profile; { my $var = eval '33'; # or just my $var = 33 # or my $var = setme_at_runtime(); $profile = { my_name => sub { ($var =~ /\d+/) ? 1: return } }; } my $fun = $profile->{my_name}; print $profile->{my_name}->( ); print $profile->{my_name}->('a'); print $profile->{my_name}->( 22 );