What can I do to reduce the repetition of writing those 2 lines for every method? Someone suggested that I use a module to handle the attributes of the methods, but I am hoping to do this without the help of a module.
Also, at the end of certain methods (about a dozen or so), I print some HTML. It is always the same HTML. I was hoping the I could use DESTROY as a means of tacking on that HTML to the method calls that need them. Would that be a good thing to do? Thanks Monks.
The documentation for Hook::WrapSub has some suggestions that apply directly to your requirements:
use Hook::WrapSub qw( wrap_subs );
wrap_subs \&before, 'some_func', 'another_func', \&after;
sub before {
croak "No arguments allowed!" if @_;
# but if you're wrapping object methods, you might want to take
# the object reference (i.e. $self) into account:
# croak "No arguments allowed" if @_ > 1;
}
sub after {
print "Always the same ...";
}
# your subs follow
Well, you could reduce it to one line I suppose. This method relies on the fact that if a sub is called with an '&' and without an explicit parameter list, it inherits @_ from its caller (see [doc://perlsub]).
use strict;
use warnings;
package TestClass;
sub has_params {
return @_ > 1 ? scalar(@_) - 1 : 0;
}
sub mytest {
die "@_\n" if &has_params;
print "We're ok.\n";
}
1;
package main;
print "Testing with no parameters.\n\t";
TestClass->mytest( );
print "Testing with one parameter.\n\t";
TestClass->mytest( "Hello" );
There is one trick though, and I'm sure you're already dealing with it somehow: When a sub is called as a method (be it a class method or an object method) it will have one parameter passed into @_; either the class name or the self object ref. That's why in my "has_params()" subroutine, I only trigger a positive if there is more than one parameter.
When you run the snippet above you'll see that it passes the first test, and dies on the second one.
Dave
sub _has_params {
return @_ > 1 ? scalar(@_) - 1 : 0;
}
How 'bout
sub _has_params { @_ - 1 }
?
It would also check if it is called as a sub with no arguments... oh, well, and it wouldn't catch a call like a sub with exactly one argument...
But then if the 'method' was invoked as a sub from within the class it could potentially have no params, leading to a return value of -1, which would give a false positive.
Dave