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| * See [http://avatraxiom.livejournal.com/58084.html The Problems of Perl]. | | * See [http://avatraxiom.livejournal.com/58084.html The Problems of Perl]. |
| * In addition, certain syntax things are confusing for new users: | | * Some more complaints from people who don't know the language (removed) |
| ** The difference between () and [].
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| ** The fact that %var is a () (which is also the array notation) but {} is $var.
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| ** 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) = @_.)
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| ** The fact that $hash{'key'} and $hash{key} are the same.
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| ** qq[] is a string (as is qq{}, etc.), q[] is a string, though qw() is an array.
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| ** &sub() is resolved at runtime but sub() is resolved at compile time, ''except'' for methods.
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| ** The conversions from one type to another can sometimes be horrendous to read. Eg: [keys %{ @{ $var } }].
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| ** $$foo[1] and $foo->[1] mean the same thing.
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| ** That numbers are compared with "==" but strings are compared with "eq", even though in other places strings are interpreted as numbers if used numerically.
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| ** 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.
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| ** That Perl errors are in $@ but system errors are in $!, and when to use which one.
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| ** That Perl doesn't really have a class system, it just has a package system with @ISA or "use base," "bless," and SUPER::.
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| ** That "my ($var) = @_" will get you the first item of the array, but "my $var = @_" will get you a number.
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| ** 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.
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| ** 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.
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| == Perl6 == | | == Perl6 == |