Class: Oga::CSS::Parser Private

Inherits:
LL::Driver
  • Object
show all
Defined in:
lib/oga/css/parser.rb

Overview

This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

AST parser for CSS expressions.

This parser does not build a CSS specific AST, instead it directly produces an XPath AST. This removes the need to transform the AST or generate corresponding XPath expressions as a String.

Similar to XPath::Parser this parser only takes String instances as input.

Constant Summary

CONFIG =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

LL::DriverConfig.new
CACHE =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future.

Returns:

LRU.new

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ Parser

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Parser

Parameters:

  • data (String)

    The input to parse.



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# File 'lib/oga/css/parser.rb', line 249

def initialize(data)
  @lexer = Lexer.new(data)
end

Class Method Details

.parse_with_cache(data) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Parameters:

  • data (String)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 244

def self.parse_with_cache(data)
  CACHE.get_or_set(data) { new(data).parse }
end

Instance Method Details

#current_elementAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns the node test for the current element.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 279

def current_element
  @current_element ||= s(:test, nil, '*')
end

#each_token {|| ... } ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Yields the next token from the lexer.

Yield Parameters:

  • (Array)


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# File 'lib/oga/css/parser.rb', line 268

def each_token
  @lexer.advance do |*args|
    yield args
  end

  yield [-1, -1]
end

#on_op_ends_with(attr, value) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the $= operator.

Parameters:

  • attr (AST::Node)
  • value (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 465

def on_op_ends_with(attr, value)
  s(
    :eq,
    s(
      :call,
      'substring',
      attr,
      s(
        :add,
        s(
          :sub,
          s(:call, 'string-length', attr),
          s(:call, 'string-length', value)
        ),
        s(:int, 1)
      ),
      s(:call, 'string-length', value)
    ),
    value
  )
end

#on_op_eq(attr, value) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the = operator.

Parameters:

  • attr (AST::Node)
  • value (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 433

def on_op_eq(attr, value)
  s(:eq, attr, value)
end

#on_op_hyphen_in(attr, value) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the |= operator.

Parameters:

  • attr (AST::Node)
  • value (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 501

def on_op_hyphen_in(attr, value)
  s(
    :or,
    s(:eq, attr, value),
    s(
      :call,
      'starts-with',
      attr,
      s(:call, 'concat', value, s(:string, '-'))
    )
  )
end

#on_op_in(attr, value) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the *= operator.

Parameters:

  • attr (AST::Node)
  • value (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 492

def on_op_in(attr, value)
  s(:call, 'contains', attr, value)
end

#on_op_space_in(attr, value) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the ~= operator.

Parameters:

  • attr (AST::Node)
  • value (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 442

def on_op_space_in(attr, value)
  s(
    :call,
    'contains',
    s(:call, 'concat', s(:string, ' '), attr, s(:string, ' ')),
    s(:call, 'concat', s(:string, ' '), value, s(:string, ' '))
  )
end

#on_op_starts_with(attr, value) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the ^= operator.

Parameters:

  • attr (AST::Node)
  • value (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 456

def on_op_starts_with(attr, value)
  s(:call, 'starts-with', attr, value)
end

#on_pseudo_class(name, arg = nil) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Parameters:

  • name (String)
  • arg (AST::Node) (defaults to: nil)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 308

def on_pseudo_class(name, arg = nil)
  handler = "on_pseudo_class_#{name.gsub('-', '_')}"

  arg ? send(handler, arg) : send(handler)
end

#on_pseudo_class_emptyAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :empty selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 406

def on_pseudo_class_empty
  s(:call, 'not', s(:axis, 'child', s(:type_test, 'node')))
end

#on_pseudo_class_first_childAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :first-child selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 364

def on_pseudo_class_first_child
  generate_no_siblings('preceding-sibling')
end

#on_pseudo_class_first_of_typeAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :first-of-type selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 378

def on_pseudo_class_first_of_type
  generate_no_siblings('preceding-sibling', current_element)
end

#on_pseudo_class_last_childAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :last-child selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 371

def on_pseudo_class_last_child
  generate_no_siblings('following-sibling')
end

#on_pseudo_class_last_of_typeAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :last-of-type selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 385

def on_pseudo_class_last_of_type
  generate_no_siblings('following-sibling', current_element)
end

#on_pseudo_class_not(arg) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :not selector.

Parameters:

  • arg (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 414

def on_pseudo_class_not(arg)
  # Unpacks (axis "descendant" (test nil "x")) into just (test nil "x") as
  # in this case we want to wrap the (test) node in a (axis "self") node.
  if arg.type == :axis
    arg = s(:axis, 'self', arg.children[1])

  # Unpack (predicate (eq ...)) into just (eq)
  elsif arg.type == :predicate
    arg = arg.children[1]
  end

  s(:call, 'not', arg)
end

#on_pseudo_class_nth(arg) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the nth pseudo class.

Parameters:

  • arg (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 357

def on_pseudo_class_nth(arg)
  s(:eq, s(:call, 'position'), arg)
end

#on_pseudo_class_nth_child(arg) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the nth-child pseudo class.

Parameters:

  • arg (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 325

def on_pseudo_class_nth_child(arg)
  generate_nth_child('preceding-sibling', arg)
end

#on_pseudo_class_nth_last_child(arg) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the nth-last-child pseudo class.

Parameters:

  • arg (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 333

def on_pseudo_class_nth_last_child(arg)
  generate_nth_child('following-sibling', arg)
end

#on_pseudo_class_nth_last_of_type(arg) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the nth-last-of-type pseudo class.

Parameters:

  • arg (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 349

def on_pseudo_class_nth_last_of_type(arg)
  generate_nth_child('following-sibling', arg, current_element)
end

#on_pseudo_class_nth_of_type(arg) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the nth-of-type pseudo class.

Parameters:

  • arg (AST::Node)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 341

def on_pseudo_class_nth_of_type(arg)
  generate_nth_child('preceding-sibling', arg, current_element)
end

#on_pseudo_class_only_childAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :only-child selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 392

def on_pseudo_class_only_child
  s(:and, on_pseudo_class_first_child, on_pseudo_class_last_child)
end

#on_pseudo_class_only_of_typeAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the :only-of-type selector.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 399

def on_pseudo_class_only_of_type
  s(:and, on_pseudo_class_first_of_type, on_pseudo_class_last_of_type)
end

#on_pseudo_class_rootAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for the root pseudo class.

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 317

def on_pseudo_class_root
  s(:call, 'not', s(:axis, 'parent', s(:test, nil, '*')))
end

#on_test(namespace, name) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Generates the AST for a node test.

Parameters:

  • namespace (String)
  • name (String)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 301

def on_test(namespace, name)
  @current_element = s(:test, namespace, name)
end

#parseAST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Parses the input and returns the corresponding AST.

Examples:

parser = Oga::CSS::Parser.new('foo.bar')
ast    = parser.parse

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 290

def parse
  reset

  super
end

#resetObject

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Resets the internal state of the parser.



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# File 'lib/oga/css/parser.rb', line 254

def reset
  @current_element = nil
end

#s(type, *children) ⇒ AST::Node

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Parameters:

  • type (Symbol)
  • children (Array)

Returns:

  • (AST::Node)


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# File 'lib/oga/css/parser.rb', line 261

def s(type, *children)
  AST::Node.new(type, children)
end