Hi
TheDamian's new book, Perl Best Practices, covers this in Chapter 9. He recommends passing a hash reference, typically to an anonymous hash.
my $foo = CalcFoo( { bar => 'abc', baz => 'def' } );
sub CalcFoo
{
my $href = $_[0];
my $foo;
if ( defined $href->{bar} and defined $href->{baz} )
{
$foo = $href->{bar} . $href->{baz};
}
else
{
print "Error: pls define bar and baz\n";
}
return $foo;
}
The reasons given for not passing a list of raw key/value pairs is:
Requiring the named arguments to be specified inside a hash ensures that any mismatch,
such as:
$line = padded({text=>$line, cols=>20..21, centered=>1, filler=>$SPACE
+});
will be reported (usually at compile time) in the caller’s context:
Odd number of elements in anonymous hash at demo.pl line 42
Passing those arguments as raw pairs:
$line = padded(text=>$line, cols=>20..21, centered=>1, filler=>$SPACE)
+;
would cause the exception to be thrown at run time, and from the line inside the
subroutine where the odd number of arguments were unpacked and assigned to a
hash:
The chapter on subroutines is currently available as a sample chapter on the O'Reilly website for you to peruse. It's a great book, highly recommended.
- j
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