Hash::AutoHash::AVPairsSingle - Object-oriented access to hash with simple (non-reference) elements
Version 1.16
use Hash::AutoHash::AVPairsSingle; # create object and set intial values my $avp=new Hash::AutoHash::AVPairsSingle name=>'Joe',hobby=>'chess'; # access or change hash elements via methods my $name=$avp->name; # 'Joe' $avp->name('Joey'); # change name to 'Joey' $avp->pets({dog=>'Spot'}); # illegal - reference # you can also use standard hash notation and functions my $name=$avp->{name}; # 'Joey' $avp->{name}='Joe'; # change name back to 'Joe' my($name,$hobby)=@$avp{qw(name hobby)}; # get 2 elements in one statement my @keys=keys %$avp; # ('name','hobby') my @values=values %$avp; # ('Joe','chess') while(my($key,$value)=each %$avp) { print "$key => @$value\n"; # prints each element as usual } delete $avp->{hobby}; # no more hobby # alias $avp to regular hash for more concise hash notation use Hash::AutoHash::AVPairsSingle qw(autohash_alias); my %hash; autohash_alias($avp,%hash); # access or change hash elements without using -> $hash{hobby}='go'; # change hobby to 'go' my $hobby=$hash{hobby}; # 'go' my($name,$hobby)=@hash{qw(name hobby)}; # get 2 elements in one statement
This is a subclass of Hash::AutoHash which wraps a tied hash whose elements are simple values like numbers and strings, not references. "AVP" stands for "attribute-value pairs". Hash::AutoHash::Record uses this class to represent attribute-value pairs parsed from text files.
Like Hash::AutoHash itself, this class lets you get or set hash elements using hash notation or by invoking a method with the same name as the key. See SYNOPSIS for examples.
Also like Hash::AutoHash, this class provides a full plate of functions for performing hash operations on Hash::AutoHash::AVPairsSingle objects. These are useful if you want to avoid hash notation all together.
And also like Hash::AutoHash, you can alias the object to a regular hash for more concise hash notation. See SYNOPSIS for examples. Admittedly, this is a minor convenience, but the reduction in verbosity can be useful in some cases.
As in Hash::AutoHash, the namespace is "clean"; any method invoked on an object is interpreted as a request to access or change an element of the underlying hash. The software accomplishes this by providing all its capabilities through class methods (these are methods, such as 'new', that are invoked on the class rather than on individual objects), functions that must be imported into the caller's namespace, and methods invoked on the tied object implementing the hash.
CAUTION: As of version 1.12, it is not possible to use method notation for keys with the same names as methods inherited from UNIVERSAL (the base class of everything). These are 'can', 'isa', 'DOES', and 'VERSION'. The reason is that as of Perl 5.9.3, calling UNIVERSAL methods as functions is deprecated and developers are encouraged to use method form instead. Previous versions of AutoHash are incompatible with CPAN modules that adopt this style.
Title : new Usage : $avp=new Hash::AutoHash::AVPairsSingle name=>'Joe',hobby=>'chess' -- OR -- $avp=new Hash::AutoHash::AVPairsSingle [name=>'Joe',hobby=>'chess'] -- OR -- $avp=new Hash::AutoHash::AVPairsSingle {name=>'Joe',hobby=>'chess'} Function: Create Hash::AutoHash::AVPairsSingle object and set elements. Returns : Hash::AutoHash::AVPairsSingle object Args : Optional list of key=>value pairs which are used to set elements of the object. Args can also be passed as ARRAY or HASH
The following functions are inherited from Hash::AutoHash and operate exactly as there. You must import them into your namespace before use.
use Hash::AutoHash::AVPairsSingle qw(autohash_alias autohash_tied autohash_get autohash_set autohash_clear autohash_delete autohash_each autohash_exists autohash_keys autohash_values autohash_count autohash_empty autohash_notempty)
Aliasing a Hash::AutoHash::AVPairsSingle object to a regular hash avoids the need to dereference the variable when using hash notation. As a convenience, the autoahash_alias functions can link in either direction depending on whether the given object exists.
Title : autohash_alias Usage : autohash_alias($avp,%hash) Function: Link $avp to %hash such that they will have exactly the same value. Args : Hash::AutoHash::AVPairsSingle object and hash Returns : Hash::AutoHash::AVPairsSingle object
You can access the object implementing the tied hash using Perl's built-in tied function or the autohash_tied function inherited from Hash::AutoHash. Advantages of autohash_tied are (1) it operates directly on the Hash::AutoHash::AVPairsSingle object without requiring a leading '%', and (2) it provide an arguably simpler syntax for invoking methods on the tied object.
Title : autohash_tied Usage : $tied=autohash_tied($avp) -- OR -- $tied=autohash_tied(%hash) -- OR -- $result=autohash_tied($avp,'some_method',@parameters) -- OR -- $result=autohash_tied(%hash,'some_method',@parameters) Function: The first two forms return the object implementing the tied hash. The latter two forms invoke a method on the tied object. In forms 1 and 3, the first argument is the Hash::AutoHash::AVPairsSingle object. In forms 2 and 4, the first argument is a hash to which a Hash::AutoHash::AVPairsSingle object has been aliased Returns : In forms 1 and 2, object implementing tied hash or undef. In forms 3 and 4, result of invoking method (which can be anything or nothing), or undef. Args : Form 1. Hash::AutoHash::AVPairsSingle object Form 2. hash to which Hash::AutoHash::AVPairsSingle object is aliased Form 3. Hash::AutoHash::AVPairsSingle object, method name, optional list of parameters for method Form 4. hash to which Hash::AutoHash::AVPairsSingle object is aliased, method name, optional list of parameters for method
Title : autohash_get Usage : ($name,$hobby)=autohash_get($avp,qw(name hobby)) Function: Get values for multiple keys. Args : Hash::AutoHash::AVPairsSingle object and list of keys Returns : list of argument values
Title : autohash_set Usage : autohash_set($avp,name=>'Joe Plumber',first_name=>'Joe') -- OR -- autohash_set($avp,['name','first_name'],['Joe Plumber','Joe']) Function: Set multiple arguments in existing object. Args : Form 1. Hash::AutoHash::AVPairsSingle object and list of key=>value pairs Form 2. Hash::AutoHash::MultiValue object, ARRAY of keys, ARRAY of values Returns : Hash::AutoHash::AVPairsSingle object
The remaining functions provide hash-like operations on Hash::AutoHash::AVPairsSingle objects. These are useful if you want to avoid hash notation all together.
Title : autohash_clear Usage : autohash_clear($avp) Function: Delete entire contents of $avp Args : Hash::AutoHash::AVPairsSingle object Returns : nothing
Title : autohash_delete Usage : autohash_delete($avp,@keys) Function: Delete keys and their values from $avp. Args : Hash::AutoHash::AVPairsSingle object, list of keys Returns : nothing
Title : autohash_exists Usage : if (autohash_exists($avp,$key)) { ... } Function: Test whether key is present in $avp. Args : Hash::AutoHash::AVPairsSingle object, key Returns : boolean
Title : autohash_each Usage : while (my($key,$value)=autohash_each($avp)) { ... } -- OR -- while (my $key=autohash_each($avp)) { ... } Function: Iterate over all key=>value pairs or all keys present in $avp Args : Hash::AutoHash::AVPairsSingle object Returns : list context: next key=>value pair in $avp or empty list at end scalar context: next key in $avp or undef at end
Title : autohash_keys Usage : @keys=autohash_keys($avp) Function: Get all keys that are present in $avp Args : Hash::AutoHash::AVPairsSingle object Returns : list of keys
Title : autohash_values Usage : @values=autohash_values($avp) Function: Get the values of all keys that are present in $avp Args : Hash::AutoHash::AVPairsSingle object Returns : list of values
Title : autohash_count Usage : $count=autohash_count($avp) Function: Get the number keys that are present in $avp Args : Hash::AutoHash::AVPairsSingle object Returns : number
Title : autohash_empty Usage : if (autohash_empty($avp)) { ... } Function: Test whether $avp is empty Args : Hash::AutoHash::AVPairsSingle object Returns : boolean
Title : autohash_notempty Usage : if (autohash_notempty($avp)) { ... } Function: Test whether $avp is not empty. Complement of autohash_empty Args : Hash::AutoHash::AVPairsSingle object Returns : boolean
perltie and Tie::Hash present background on tied hashes.
Hash::AutoHash provides the object wrapping machinery. The documentation of that class includes a detailed list of caveats and cautions. Hash::AutoHash::Args, Hash::AutoHash::MultiValued, Hash::AutoHash::AVPairsMulti, Hash::AutoHash::Record are other subclasses of Hash::AutoHash.
Hash::AutoHash::AVPairsMulti is similar but allows each attribute to have multiple values.
Hash::AutoHash::Record uses this class to to represent attribute-value pairs parsed from text files.
Nat Goodman, <natg at shore.net>
<natg at shore.net>
Please report any bugs or feature requests to bug-hash-autohash-avpairssingle at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-AutoHash-AVPairsSingle. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
bug-hash-autohash-avpairssingle at rt.cpan.org
You can find documentation for this module with the perldoc command.
perldoc Hash::AutoHash::AVPairsSingle
You can also look for information at:
RT: CPAN's request tracker
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-AutoHash-AVPairsSingle
AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/Hash-AutoHash-AVPairsSingle
CPAN Ratings
http://cpanratings.perl.org/d/Hash-AutoHash-AVPairsSingle
Search CPAN
http://search.cpan.org/dist/Hash-AutoHash-AVPairsSingle/
Copyright 2009 Nat Goodman.
This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.
See http://dev.perl.org/licenses/ for more information.
To install Hash::AutoHash::AVPairsSingle, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Hash::AutoHash::AVPairsSingle
CPAN shell
perl -MCPAN -e shell install Hash::AutoHash::AVPairsSingle
For more information on module installation, please visit the detailed CPAN module installation guide.