Code Index:

package CSS::SAC::Selector
EOF

NAME

CSS::SAC::Selector - base class for SAC selectors

SYNOPSIS

  use CSS::SAC::Selector qw(:constants);
  foo if $sel->is_type(SELECTOR_TYPE_CONSTANT);

DESCRIPTION

SAC Selectors describe selectors that can be expressed in CSS such as ElementSelector or SiblingSelector. This class provides everything that is needed to implement simple selectors (methods, constants) as well as what is needed by subclasses defining more complex selectors.

The constants are those defined in the SAC spec, with the leading SAC_ removed. What the constants map to is to be considered an opaque token that can be tested for equality. If there is demand for it, I will add a way to add new constants (for people wishing to define new condition types).

I have also added the UNKNOWN_SELECTOR constant. It shouldn't occur in normal processing but it's always useful to have such fallback values.

The Selector interface adds $sel->is_type($selector_type) to the interface defined in the SAC spec. This allows for more flexible type checking. The advantages are the same as those described for the same extension in the CSS::SAC::Condition class.

CONSTANTS

* UNKNOWN_SELECTOR
* ANY_NODE_SELECTOR
* CDATA_SECTION_NODE_SELECTOR
* CHILD_SELECTOR
* COMMENT_NODE_SELECTOR
* CONDITIONAL_SELECTOR
* DESCENDANT_SELECTOR
* DIRECT_ADJACENT_SELECTOR
* ELEMENT_NODE_SELECTOR
* NEGATIVE_SELECTOR
* PROCESSING_INSTRUCTION_NODE_SELECTOR
* PSEUDO_ELEMENT_SELECTOR
* ROOT_NODE_SELECTOR
* TEXT_NODE_SELECTOR

METHODS

* CSS::SAC::Selector->new($type) or $sel->new($type): Creates a new selector. The $type must be one of the type constants.
* $sel->SelectorType() or $sel->getSelectorType: Returns the constant corresponding to the type of this selector.
* $sel->is_type($selector_type): Returns a boolean indicating whether this selector is of type $selector_type (a selector constant).

AUTHOR

Robin Berjon <robin@knowscape.com>

This module is licensed under the same terms as Perl itself.

### # CSS::SAC::Selector - base class for SAC selectors # Robin Berjon <robin@knowscape.com> # 24/02/2001 ### package CSS::SAC::Selector; use strict; use vars qw($VERSION); $VERSION = $CSS::SAC::VERSION || '0.03'; #---------------------------------------------------------------------# # build the fields for an array based object #---------------------------------------------------------------------# use Class::ArrayObjects define => { fields => [qw(_type_)], }; #---------------------------------------------------------------------# ### Constants ######################################################### # # # # sub UNKNOWN_SELECTOR () { 1 } sub ANY_NODE_SELECTOR () { 2 } sub CDATA_SECTION_NODE_SELECTOR () { 3 } sub CHILD_SELECTOR () { 4 } sub COMMENT_NODE_SELECTOR () { 5 } sub CONDITIONAL_SELECTOR () { 6 } sub DESCENDANT_SELECTOR () { 7 } sub DIRECT_ADJACENT_SELECTOR () { 8 } sub ELEMENT_NODE_SELECTOR () { 9 } sub NEGATIVE_SELECTOR () { 10 } sub PROCESSING_INSTRUCTION_NODE_SELECTOR () { 11 } sub PSEUDO_ELEMENT_SELECTOR () { 12 } sub ROOT_NODE_SELECTOR () { 13 } sub TEXT_NODE_SELECTOR () { 14 } # EXPERIMENTAL SELECTOR sub INDIRECT_ADJACENT_SELECTOR () { 15 } #---------------------------------------------------------------------# # import() # all import can do is export the constants #---------------------------------------------------------------------# sub import { my $class = shift; my $tag = shift || ''; # check that we have the right tag return unless $tag eq ':constants'; # define some useful vars my $pkg = caller; my @constants = qw( UNKNOWN_SELECTOR ANY_NODE_SELECTOR CDATA_SECTION_NODE_SELECTOR CHILD_SELECTOR COMMENT_NODE_SELECTOR CONDITIONAL_SELECTOR DESCENDANT_SELECTOR DIRECT_ADJACENT_SELECTOR ELEMENT_NODE_SELECTOR NEGATIVE_SELECTOR PROCESSING_INSTRUCTION_NODE_SELECTOR PSEUDO_ELEMENT_SELECTOR ROOT_NODE_SELECTOR TEXT_NODE_SELECTOR INDIRECT_ADJACENT_SELECTOR ); # now lets create the constants in the caller's package no strict 'refs'; for my $c (@constants) { my $qname = "${pkg}::$c"; *$qname = \&{$c}; } } #---------------------------------------------------------------------# # # # # ### Constants ######################################################### ### Constructor ####################################################### # # # # #---------------------------------------------------------------------# # CSS::SAC::Selector->new($type) # creates a new sac selector object #---------------------------------------------------------------------# sub new { my $class = ref($_[0])?ref(shift):shift; my $type = shift; return bless [$type], $class; } #---------------------------------------------------------------------# # # # # ### Constructor ####################################################### ### Accessors ######################################################### # # # # #---------------------------------------------------------------------# # my $type = $sel->SelectorType() # $sel->SelectorType($type) # get/set the selector type #---------------------------------------------------------------------# sub SelectorType { (@_==2) ? $_[0]->[_type_] = $_[1] : $_[0]->[_type_]; } #---------------------------------------------------------------------# *CSS::SAC::Selector::getSelectorType = \&SelectorType; #---------------------------------------------------------------------# # $sel->is_type($selector_constant) # returns true is this selector is of type $selector_constant #---------------------------------------------------------------------# sub is_type { return $_[0]->[_type_] == $_[1]; } #---------------------------------------------------------------------# # # # # ### Accessors ######################################################### 1;