Re^3: defining constant in other package

in reply to Re^2: defining constant in other package
in thread defining constant in other package

Perl wants a constant (subroutine) to have an empty prototype before it eliminates code guarded by it:

BEGIN {
    sub MyPackg::DBG() {
        0;
    }
    
}
our $a = 1;
package MyPackg;
print 'DEBUGGING' if DBG();  # <-- oops
print 'huhu';
[download]

gives this output:

F:\>perl -MO=Deparse tmp.pl
sub MyPackg::DBG () { 0 }
sub BEGIN {

}
our $a = 1;
package MyPackg;
'???';
print 'huhu';
tmp.pl syntax OK
[download]

In Section Seekers of Perl Wisdom