NAME

CSS::SAC::LexicalUnit - SAC units

SYNOPSIS

  use CSS::SAC::LexicalUnit qw(:constants);
  foo if $lu->is_type(LU_TYPE_CONSTANT);

DESCRIPTION

In the SAC spec, LexicalUnit is a linked list, that is, you only ever hold one LexicalUnit, and you ask for the next of for the previous one when you want to move on.

Such a model seems awkward, though I'm sure it makes sense somehow in Java, likely for a Java-specific reason.

In the Perl implementation, I have changed this. A LexicalUnit is an object that stands on it's own and has no next/previous objects. Instead, the $handler->property callback gets called with a LexicalUnitList, which is in fact just an array ref of LexicalUnits.

We also don't differentiate between IntegerValue, FloatValue, and StringValue, it's always Value in Perl. This also applies to Parameters and SubValues. Both are called as Value and return an array ref of LexicalUnits.

I added the is_type() method, see CSS::SAC::Condition for advantages of that approach.

CONSTANTS

ATTR
CENTIMETER
COUNTER_FUNCTION
COUNTERS_FUNCTION
DEGREE
DIMENSION
EM
EX
FUNCTION
GRADIAN
HERTZ
IDENT
INCH
INHERIT
INTEGER
KILOHERTZ
MILLIMETER
MILLISECOND
OPERATOR_COMMA
OPERATOR_EXP
OPERATOR_GE
OPERATOR_GT
OPERATOR_LE
OPERATOR_LT
OPERATOR_MINUS
OPERATOR_MOD
OPERATOR_MULTIPLY
OPERATOR_PLUS
OPERATOR_SLASH
OPERATOR_TILDE
PERCENTAGE
PICA
PIXEL
POINT
RADIAN
REAL
RECT_FUNCTION
RGBCOLOR
SECOND
STRING_VALUE
SUB_EXPRESSION
UNICODERANGE
URI

METHODS

CSS::SAC::LexicalUnit->new($type,$text,$value) or $lu->new($type,$text,$value)
Creates a new unit. The $type must be one of the type constants, the text depends on the type of unit (unit text, func name, etc...), and the value is the content of the lu.
$lu->DimensionUnitText([$dut]) or getDimensionUnitText
get/set the text of the dimension unit (eg cm, px, etc...)
$lu->FunctionName([$fn]) or getFunctionName
get/set the name of the function (eg attr, uri, etc...)
$lu->Value([$value]) or getValue
get/set the value of the lu (which may be another lu, or a lu list)
$lu->LexicalUnitType([$type]) or getLexicalUnitType
get/set the type of the lu
$lu->is_type($lu_constant)
returns true is this lu is of type $lu_constant

AUTHOR

Robin Berjon <robin@knowscape.com>

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