@@ -215,8 +215,9 @@ passing a hash produces a list of key/value pairs: The C<show_pets()> function works because the C<%pet_names_and_types> hash flattens into the list C<'Lucky', 'dog', 'Rodney', 'dog', 'Tuxedo', 'cat', -'Petunia', 'cat'>. The assignment within C<show_pets()> works effectively as -the assignment to C<%pet_names_and_types> does. +'Petunia', 'cat'>. The hash assignment inside the function C<show_pets()> +works essentially as the more explicit assignment to C<%pet_names_and_types> +does. This is often useful, but there are limitations to understand. If you wish to make a C<show_pets_of_type()> function, where one parameter is the I<type> of @@ -231,8 +232,8 @@ C<pop> to remove it from the end of C<@_>): while (my ($name, $species) = each %pets) { - B<next unless $species eq $type;> - say "$name is a $species"; + B<next unless $species eq $type;> ## Isn't using 'unless' frowned upon? + say "$name is a $species"; ## according to PBP? (jeremiah) } } @@ -314,7 +315,7 @@ modules on the CPAN for declarative parameter handling. Defensive programming often benefits from checking types and values of arguments for appropriateness before performing further processing. By default, Perl 5 provides few built-in mechanisms for doing so (in some cases, -L<prototypes> can I<help>, but that's not their primary purpose). You can +L<prototypes> can I<help>, but that's not their primary purpose). You can check that the I<number> of parameters passed to a function is correct by evaluating C<@_> in scalar context: @@ -373,8 +374,9 @@ names: Functions in namespaces are I<visible> outside of those namespaces in the sense that you can refer to them directly, but they are only callable by their short -names from within the namespace, unless you have somehow made them available to -the current namespace by a process called importing and exporting. +names from within the namespace in which they are declared, unless you have +somehow made them available to the current namespace through the processes of +importing and exporting. =head3 Importing @@ -428,7 +430,7 @@ has compiled the entire statement. =for review Discuss unimporting? In my experience, it's not nearly as well supported as -importing. +importing. (I agree with you, I rarely (okay, never) use it.) (jeremiah) =end for @@ -438,6 +440,8 @@ importing. Does this belong instead in the Modules chapter? ++1 (jeremiah) + =end for X<functions; exporting> sections/functions.pod d57e55b864e5d0b4ea354afc8ee20ba64c1b1741 99c78c9b3115d1624618d481ef6525055ea3a7e9 chromatic chromatic@wgz.org http://github.com/chromatic/modern_perl_book/commit/cd6ab69edc5e9beaa2a321d52ce9671432822c25 cd6ab69edc5e9beaa2a321d52ce9671432822c25 2009-11-05T16:58:26-08:00 2009-11-05T16:58:26-08:00 Merge branch 'master' of git://github.com/jeremiah/modern_perl_book into jeremiah/master 058a107ca333692780c570cb2def404ddfa62a80 chromatic chromatic@wgz.org