diff options
Diffstat (limited to 'pod/perllol.pod')
-rw-r--r-- | pod/perllol.pod | 48 |
1 files changed, 4 insertions, 44 deletions
diff --git a/pod/perllol.pod b/pod/perllol.pod index 4b58bee0b2..11632e0c97 100644 --- a/pod/perllol.pod +++ b/pod/perllol.pod @@ -1,8 +1,10 @@ -=head1 TITLE +=head1 NAME perlLoL - Manipulating Lists of Lists in Perl -=head1 Declaration and Access +=head1 DESCRIPTION + +=head1 Declaration and Access of Lists of Lists The simplest thing to build is a list of lists (sometimes called an array of arrays). It's reasonably easy to understand, and almost everything @@ -300,48 +302,6 @@ If I were you, I'd put that in a function: } -=head1 Passing Arguments - -One place where a list of lists crops up is when you pass -in several list references to a function. Consider: - - @tailings = popmany ( \@a, \@b, \@c, \@d ); - - sub popmany { - my $aref; - my @retlist = (); - foreach $aref ( @_ ) { - push @retlist, pop @$aref; - } - return @retlist; - } - -This function was designed to pop off the last element from each of -its arguments and return those in a list. In this function, -you can think of @_ as a list of lists. - -Just as a side note, what happens if the function is called with the -"wrong" types of arguments? Normally nothing, but in the case of -references, we can be a bit pickier. This isn't detectable at -compile-time (yet--Larry does have a prototype prototype in the works for -5.002), but you could check it at run time using the ref() function. - - use Carp; - for $i ( 0 .. $#_) { - if (ref($_[$i]) ne 'ARRAY') { - confess "popmany: arg $i not an array reference\n"; - } - } - -However, that's not usually necessary unless you want to trap it. It's -also dubious in that it would fail on a real array references blessed into -its own class (an object). But since you're all going to be using -C<strict refs>, it would raise an exception anyway even without the die. - -This will matter more to you later on when you start building up -more complex data structures that all aren't woven of the same -cloth, so to speak. - =head1 SEE ALSO perldata(1), perlref(1), perldsc(1) |