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Diffstat (limited to 'pod/perldsc.pod')
| -rw-r--r-- | pod/perldsc.pod | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/pod/perldsc.pod b/pod/perldsc.pod index 11304a67ac..158322b61c 100644 --- a/pod/perldsc.pod +++ b/pod/perldsc.pod @@ -1,4 +1,5 @@ =head1 NAME +X<data structure> X<complex data structure> X<struct> perldsc - Perl Data Structures Cookbook @@ -68,6 +69,7 @@ But for now, let's look at general issues common to all these types of data structures. =head1 REFERENCES +X<reference> X<dereference> X<dereferencing> X<pointer> The most important thing to understand about all data structures in Perl -- including multidimensional arrays--is that even though they might @@ -75,6 +77,7 @@ appear otherwise, Perl C<@ARRAY>s and C<%HASH>es are all internally one-dimensional. They can hold only scalar values (meaning a string, number, or a reference). They cannot directly contain other arrays or hashes, but instead contain I<references> to other arrays or hashes. +X<multidimensional array> X<array, multidimensional> You can't use a reference to an array or hash in quite the same way that you would a real array or hash. For C or C++ programmers unused to @@ -174,6 +177,7 @@ in memory! In C, you'd have to remember to malloc() yourself some new memory. In Perl, you'll want to use the array constructor C<[]> or the hash constructor C<{}> instead. Here's the right way to do the preceding broken code fragments: +X<[]> X<{}> for $i (1..10) { @array = somefunc($i); @@ -248,9 +252,11 @@ In summary: =head1 CAVEAT ON PRECEDENCE +X<dereference, precedence> X<dereferencing, precedence> Speaking of things like C<@{$AoA[$i]}>, the following are actually the same thing: +X<< -> >> $aref->[2][2] # clear $$aref[2][2] # confusing @@ -298,6 +304,10 @@ variable, and it would thereby remind you to write instead: print $aref->[2][2] =head1 DEBUGGING +X<data structure, debugging> X<complex data structure, debugging> +X<AoA, debugging> X<HoA, debugging> X<AoH, debugging> X<HoH, debugging> +X<array of arrays, debugging> X<hash of arrays, debugging> +X<array of hashes, debugging> X<hash of hashes, debugging> Before version 5.002, the standard Perl debugger didn't do a very nice job of printing out complex data structures. With 5.002 or above, the @@ -331,6 +341,7 @@ here are short code examples illustrating access of various types of data structures. =head1 ARRAYS OF ARRAYS +X<array of arrays> X<AoA> =head2 Declaration of an ARRAY OF ARRAYS @@ -387,6 +398,7 @@ types of data structures. } =head1 HASHES OF ARRAYS +X<hash of arrays> X<HoA> =head2 Declaration of a HASH OF ARRAYS @@ -465,6 +477,7 @@ types of data structures. } =head1 ARRAYS OF HASHES +X<array of hashes> X<AoH> =head2 Declaration of an ARRAY OF HASHES @@ -555,6 +568,7 @@ types of data structures. } =head1 HASHES OF HASHES +X<hass of hashes> X<HoH> =head2 Declaration of a HASH OF HASHES @@ -673,6 +687,7 @@ types of data structures. =head1 MORE ELABORATE RECORDS +X<record> X<structure> X<struct> =head2 Declaration of MORE ELABORATE RECORDS |