Bugzilla:Languages: Difference between revisions

Bugzilla:Languages (view source)

Revision as of 18:04, 13 May 2007

1,944 bytes added , 13 May 2007

→‎Perl Cons: Don't remove this again for any reason, Aaron. You can discuss it in the Discussion page with me, if you want.

MaxKanatAlexander

canmove, Confirmed users

345

edits

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 * See [http://avatraxiom.livejournal.com/58084.html The Problems of Perl].
-* In addition, certain syntax things are confusing for a small minority of new users (from mkanat)
+* In addition, certain syntax things are confusing for new users (from mkanat):
+** The difference between () and [].
+** The fact that %var is a () (which is also the array notation) but {} is $var.
+** The fact that subroutine arguments aren't really subroutine arguments, they're just an array that gets passed to a function. (This also brings up confusion on the difference between using $_[1], my $var = shift, and my ($var) = @_.)
+** The fact that $hash{'key'} and $hash{key} are the same.
+** qq[] is a string (as is qq{}, etc.), q[] is a string, though qw() is an array.
+** &sub() is resolved at runtime but sub() is resolved at compile time, ''except'' for methods.
+** The conversions from one type to another can sometimes be horrendous to read. Eg: [keys %{ @{ $var } }].
+** $$foo[1] and $foo->[1] mean the same thing.
+** That numbers are compared with "==" but strings are compared with "eq", even though in other places strings are interpreted as numbers if used numerically.
+** Figuring out what's $1, $2, $3, etc. from a regex result. And the fact that $1 and $2 don't get reset if there's no match.
+*** Perl 5.10 will have named captures.
+** That Perl errors are in $@ but system errors are in $!, and when to use which one.
+** That Perl doesn't really have a class system, it just has a package system with @ISA or "use base," "bless," and SUPER::.
+** That "my ($var) = @_" will get you the first item of the array, but "my $var = @_" will get you a number.
+** In a hash created with (), if you accidentally have invalid items, you have an invalid hash. That is, you can't really do %hash = (key1 => $cgi->param('unset_param'), key2 => 'something'), because then you'll actually just have an invalid hash. (key1 will equal "key2" and "something" won't even have a real value.) In general it's safer to always make hashrefs when in doubt.
+** In array context, $cgi->param('value') returns an ''empty list'' if "value" wasn't passed to the CGI. It doesn't return undef. This is why we have "scalar $cgi->param()" all over the code.
 == Perl6 ==