Class: Twig::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/twig/parser.rb

Constant Summary collapse

STACKABLE = 
%i[
  stream
  parent
  blocks
  block_stack
  macros
  imported_symbols
  traits
  embedded_templates
  ignore_unknown_twig_callables
].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(environment) ⇒ Parser

Returns a new instance of Parser.

Parameters:



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# File 'lib/twig/parser.rb', line 25

def initialize(environment)
  @environment = environment
  @parsers = environment.expression_parsers
  @stack = []
end

Instance Attribute Details

#block_stack ⇒ Object (readonly)

Returns the value of attribute block_stack.



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# File 'lib/twig/parser.rb', line 7

def block_stack
  @block_stack
end

#environment ⇒ Environment (readonly)

Returns:



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# File 'lib/twig/parser.rb', line 10

def environment
  @environment
end

#stream ⇒ TokenStream (readonly)

Returns:



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# File 'lib/twig/parser.rb', line 6

class Parser
  attr_reader :stream, :block_stack

  # @return [Environment]
  attr_reader :environment

  STACKABLE = %i[
    stream
    parent
    blocks
    block_stack
    macros
    imported_symbols
    traits
    embedded_templates
    ignore_unknown_twig_callables
  ].freeze

  # @param [Environment] environment
  def initialize(environment)
    @environment = environment
    @parsers = environment.expression_parsers
    @stack = []
  end

  # @param [TokenStream] stream
  # @return [Node::Module]
  def parse(stream, test = nil, drop_needle: false)
    # Save the current value to stack
    frame = {}
    STACKABLE.each do |attr|
      frame[attr] = instance_variable_get("@#{attr}")
    end

    @stack << frame
    @stream = stream
    @parent = nil
    @traits = AutoHash.new
    @macros = {}
    @blocks = {}
    @embedded_templates = AutoHash.new
    @block_stack = []
    @imported_symbols = [{}]
    @ignore_unknown_twig_callables = false

    begin
      body = subparse(test, drop_needle:)

      if !@parent.nil? && (body = filter_body_nodes(body)).nil?
        body = Node::Empty.new
      end
    rescue Error::Syntax => e
      unless e.source_context
        e.source_context = stream.source
      end

      unless e.lineno
        e.lineno = stream.current.lineno
      end

      raise e
    end

    node = Node::Module.new(
      Node::Body.new({ 0 => body }),
      @parent,
      @blocks.empty? ? Node::Empty.new : Node::Nodes.new(@blocks),
      @macros.empty? ? Node::Empty.new : Node::Nodes.new(@macros),
      @traits.empty? ? Node::Empty.new : Node::Nodes.new(@traits),
      @embedded_templates.empty? ? Node::Empty.new : Node::Nodes.new(@embedded_templates),
      stream.source
    )

    @visitors ||= environment.node_visitors

    node = NodeTraverser.
      new(environment, @visitors).
      traverse(node)

    # Restore stack
    frame = @stack.pop
    STACKABLE.each do |attr|
      instance_variable_set("@#{attr}", frame[attr])
    end

    node
  end

  # @param [Method, nil] test
  # @return [Node::Base]
  def subparse(test, drop_needle: false)
    lineno = current_token.lineno
    rv = AutoHash.new

    until stream.eof?
      case current_token.type
      when Token::TEXT_TYPE
        token = stream.next
        rv.add(Node::Text.new(token.value, token.lineno))
      when Token::VAR_START_TYPE
        token = stream.next
        expr = parse_expression
        stream.expect(Token::VAR_END_TYPE)

        rv.add(Node::Print.new(expr, token.lineno))
      when Token::BLOCK_START_TYPE
        stream.next
        token = current_token

        unless token.type == Token::NAME_TYPE
          raise Error::Syntax.new('A block must start with a tag name.', token.lineno, stream.source)
        end

        if test&.call(token)
          stream.next if drop_needle
          return rv.values.first if rv.length == 1

          return Node::Nodes.new(rv, lineno)
        end

        subparser = @environment.token_parser(token.value)

        unless subparser
          if test.nil?
            raise Error::Syntax.new("Unknown \"#{token.value}\" tag.", token.lineno, stream.source)
          else
            e = Error::Syntax.new("Unexpected \"#{token.value}\" tag", token.lineno, stream.source)

            if test.respond_to?(:receiver) && (receiver = test.receiver) && receiver.is_a?(Twig::TokenParser::Base)
              e.append_message(
                " (expecting closing tag for the \"#{receiver.tag}\" tag defined near line #{lineno})."
              )
            end

            raise e
          end
        end

        stream.next
        subparser.parser = self
        node = subparser.parse(token)

        raise 'Cannot return nil from TokenParser' unless node

        node.tag = subparser.tag

        rv.add(node)
      else
        raise "Unable to parse token of type #{current_token.type}"
      end
    end

    Node::Nodes.new(rv)
  end

  def subparse_ignore_unknown_twig_callables(test, drop_needle: false)
    previous = @ignore_unknown_twig_callables
    @ignore_unknown_twig_callables = true

    begin
      subparse(test, drop_needle:)
    ensure
      @ignore_unknown_twig_callables = previous
    end
  end

  # @return [Token]
  def current_token
    stream.current
  end

  def parse_expression(precedence = 0)
    token = current_token
    if token.test(Token::OPERATOR_TYPE) && (parser = parsers.by_name(:prefix, token.value))
      stream.next
      expr = parser.parse(self, token)
    else
      expr = parsers.by_class(ExpressionParser::Prefix::Literal.name).parse(self, token)
    end

    token = current_token
    while token.test(Token::OPERATOR_TYPE) &&
          (parser = parsers.by_name(:infix, token.value)) &&
          parser.precedence >= precedence

      stream.next
      expr = parser.parse(self, expr, token)
      token = current_token
    end

    expr
  end

  # @return [TwigFilter]
  def filter(name, lineno)
    unless (filter = environment.filter(name))
      unless ignore_unknown_twig_callables?
        raise Error::Syntax.new("Unknown '#{name}' filter.", lineno, stream.source)
      end

      filter = TwigFilter.new(name, -> {})
    end

    filter
  end

  # @return [TwigFunction, Node::Expression::HelperMethod]
  def function(name, args, lineno)
    unless (function = environment.function(name))
      if ignore_unknown_twig_callables?
        return TwigFunction.new(name, -> {})
      elsif environment.allow_helper_methods?
        return Node::Expression::HelperMethod.new(name, args, lineno)
      else
        raise Error::Syntax.new("Unknown \"#{name}\" function.", lineno, stream.source)
      end
    end

    function
  end

  # @param [Integer] line
  # @return [TwigTest]
  def test(line)
    name = stream.expect(Token::NAME_TYPE).value

    if stream.test(Token::NAME_TYPE)
      # try 2 word tests
      name = "#{name} #{current_token.value}"

      if (test = environment.test(name))
        stream.next
      end
    else
      test = environment.test(name)
    end

    if test.nil? && ignore_unknown_twig_callables?
      test = TwigTest.new(name, -> {})
    end

    unless test
      raise Error::Syntax.new("Unknown #{name} test.", line, stream.source)
    end

    test
  end

  # @return [ExpressionParser]
  def expression_parser
    @expression_parser ||= ExpressionParser.new(self, @environment)
  end

  # @return [Boolean]
  def inheritance?
    @parent || @traits.length.positive?
  end

  def main_scope?
    @imported_symbols.one?
  end

  def push_local_scope
    @imported_symbols.unshift({})
  end

  def pop_local_scope
    @imported_symbols.shift
  end

  def add_imported_symbol(type, symbol_alias, name = nil, internal_ref = nil)
    @imported_symbols[0][type] ||= {}
    @imported_symbols[0][type][symbol_alias] = { name:, node: internal_ref }
  end

  def imported_symbol(type, symbol_alias)
    if (symbol = @imported_symbols.dig(0, type, symbol_alias))
      symbol
    else
      @imported_symbols.dig(-1, type, symbol_alias)
    end
  end

  # @param [Node::Module] template
  def embed_template(template)
    template.index = rand(2**32)

    @embedded_templates << template
  end

  def peek_block_stack
    @block_stack[-1]
  end

  def pop_block_stack
    @block_stack.pop
  end

  def push_block_stack(name)
    @block_stack << name
  end

  def block?(name)
    @blocks.key?(name)
  end

  def add_trait(trait)
    @traits << trait
  end

  # @param [String] name
  # @param [Node::Macro] node
  def set_macro(name, node)
    @macros[name] = node
  end

  # @param [String] name
  # @param [Node::Body] value
  def set_block(name, value)
    if @blocks.key?(name)
      raise Error::Syntax.new(
        "The block '#{name}' has already been defined line #{@blocks[name].lineno}.",
        current_token.lineno,
        @blocks[name].source_context
      )
    end

    @blocks[name] = Node::Body.new({ 0 => value }, {}, value.lineno)
  end

  # @param [Node::Base] parent
  def parent=(parent)
    if @parent
      raise Error::Syntax.new('Cannot extends twice', parent.lineno, parent.source_context)
    end

    @parent = parent
  end

  def ignore_unknown_twig_callables?
    @ignore_unknown_twig_callables
  end

  private

  # @return [ExpressionParser::ExpressionParsers]
  attr_reader :parsers

  def filter_body_nodes(node, nested: false)
    # check that the body does not contain non-empty output nodes
    if (node.is_a?(Node::Text) && !node.attributes[:data].match?(/\A[[:space:]]*\z/)) ||
       (!node.is_a?(Node::Text) && !node.is_a?(Node::BlockReference) && node.is_a?(Node::Output))
      if node.to_s.include?("\xEF\xBB\xBF")
        t = node.attributes[:data][3..]
        # bypass empty nodes starting with a BOM
        if t == '' || t.match?(/\A[[:space:]]*\z/)
          return nil
        end
      end

      raise Error::Syntax.new(
        'A template that extends another one cannot include content outside Twig blocks. Did you forget ' \
        'to put the content inside a {% block %} tag?',
        node.lineno,
        stream.source
      )
    end

    # Bypass nodes that "capture" the output
    if node.is_a?(Node::Set)
      return node
    end

    # "block" tags that are not captured (see above) are only used for defining
    # the content of the block. In such a case, nesting it does not work as
    # expected as the definition is not part of the default template code flow.
    if nested && node.is_a?(Node::BlockReference)
      raise Error::Syntax.new(
        'A block definition cannot be nested under non-capturing nodes.',
        node.lineno,
        stream.source
      )
    end

    if node.is_a?(Node::Output)
      return nil
    end

    nested ||= !node.is_a?(Node::Nodes)
    node.nodes.each do |k, n|
      if filter_body_nodes(n, nested: nested).nil?
        node.nodes.delete(k)
      end
    end

    node
  end
end

Instance Method Details

#add_imported_symbol(type, symbol_alias, name = nil, internal_ref = nil) ⇒ Object 



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# File 'lib/twig/parser.rb', line 276

def add_imported_symbol(type, symbol_alias, name = nil, internal_ref = nil)
  @imported_symbols[0][type] ||= {}
  @imported_symbols[0][type][symbol_alias] = { name:, node: internal_ref }
end

#add_trait(trait) ⇒ Object 



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# File 'lib/twig/parser.rb', line 312

def add_trait(trait)
  @traits << trait
end

#block?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twig/parser.rb', line 308

def block?(name)
  @blocks.key?(name)
end

#current_token ⇒ Token

Returns:



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# File 'lib/twig/parser.rb', line 173

def current_token
  stream.current
end

#embed_template(template) ⇒ Object

Parameters:



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# File 'lib/twig/parser.rb', line 290

def embed_template(template)
  template.index = rand(2**32)

  @embedded_templates << template
end

#expression_parser ⇒ ExpressionParser

Returns:



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# File 'lib/twig/parser.rb', line 255

def expression_parser
  @expression_parser ||= ExpressionParser.new(self, @environment)
end

#filter(name, lineno) ⇒ TwigFilter

Returns:



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# File 'lib/twig/parser.rb', line 200

def filter(name, lineno)
  unless (filter = environment.filter(name))
    unless ignore_unknown_twig_callables?
      raise Error::Syntax.new("Unknown '#{name}' filter.", lineno, stream.source)
    end

    filter = TwigFilter.new(name, -> {})
  end

  filter
end

#function(name, args, lineno) ⇒ TwigFunction, Node::Expression::HelperMethod

Returns:



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# File 'lib/twig/parser.rb', line 213

def function(name, args, lineno)
  unless (function = environment.function(name))
    if ignore_unknown_twig_callables?
      return TwigFunction.new(name, -> {})
    elsif environment.allow_helper_methods?
      return Node::Expression::HelperMethod.new(name, args, lineno)
    else
      raise Error::Syntax.new("Unknown \"#{name}\" function.", lineno, stream.source)
    end
  end

  function
end

#ignore_unknown_twig_callables? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twig/parser.rb', line 345

def ignore_unknown_twig_callables?
  @ignore_unknown_twig_callables
end

#imported_symbol(type, symbol_alias) ⇒ Object 



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# File 'lib/twig/parser.rb', line 281

def imported_symbol(type, symbol_alias)
  if (symbol = @imported_symbols.dig(0, type, symbol_alias))
    symbol
  else
    @imported_symbols.dig(-1, type, symbol_alias)
  end
end

#inheritance? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twig/parser.rb', line 260

def inheritance?
  @parent || @traits.length.positive?
end

#main_scope? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/twig/parser.rb', line 264

def main_scope?
  @imported_symbols.one?
end

#parent=(parent) ⇒ Object

Parameters:



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# File 'lib/twig/parser.rb', line 337

def parent=(parent)
  if @parent
    raise Error::Syntax.new('Cannot extends twice', parent.lineno, parent.source_context)
  end

  @parent = parent
end

#parse(stream, test = nil, drop_needle: false) ⇒ Node::Module

Parameters:

Returns:



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# File 'lib/twig/parser.rb', line 33

def parse(stream, test = nil, drop_needle: false)
  # Save the current value to stack
  frame = {}
  STACKABLE.each do |attr|
    frame[attr] = instance_variable_get("@#{attr}")
  end

  @stack << frame
  @stream = stream
  @parent = nil
  @traits = AutoHash.new
  @macros = {}
  @blocks = {}
  @embedded_templates = AutoHash.new
  @block_stack = []
  @imported_symbols = [{}]
  @ignore_unknown_twig_callables = false

  begin
    body = subparse(test, drop_needle:)

    if !@parent.nil? && (body = filter_body_nodes(body)).nil?
      body = Node::Empty.new
    end
  rescue Error::Syntax => e
    unless e.source_context
      e.source_context = stream.source
    end

    unless e.lineno
      e.lineno = stream.current.lineno
    end

    raise e
  end

  node = Node::Module.new(
    Node::Body.new({ 0 => body }),
    @parent,
    @blocks.empty? ? Node::Empty.new : Node::Nodes.new(@blocks),
    @macros.empty? ? Node::Empty.new : Node::Nodes.new(@macros),
    @traits.empty? ? Node::Empty.new : Node::Nodes.new(@traits),
    @embedded_templates.empty? ? Node::Empty.new : Node::Nodes.new(@embedded_templates),
    stream.source
  )

  @visitors ||= environment.node_visitors

  node = NodeTraverser.
    new(environment, @visitors).
    traverse(node)

  # Restore stack
  frame = @stack.pop
  STACKABLE.each do |attr|
    instance_variable_set("@#{attr}", frame[attr])
  end

  node
end

#parse_expression(precedence = 0) ⇒ Object 



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# File 'lib/twig/parser.rb', line 177

def parse_expression(precedence = 0)
  token = current_token
  if token.test(Token::OPERATOR_TYPE) && (parser = parsers.by_name(:prefix, token.value))
    stream.next
    expr = parser.parse(self, token)
  else
    expr = parsers.by_class(ExpressionParser::Prefix::Literal.name).parse(self, token)
  end

  token = current_token
  while token.test(Token::OPERATOR_TYPE) &&
        (parser = parsers.by_name(:infix, token.value)) &&
        parser.precedence >= precedence

    stream.next
    expr = parser.parse(self, expr, token)
    token = current_token
  end

  expr
end

#peek_block_stack ⇒ Object 



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# File 'lib/twig/parser.rb', line 296

def peek_block_stack
  @block_stack[-1]
end

#pop_block_stack ⇒ Object 



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# File 'lib/twig/parser.rb', line 300

def pop_block_stack
  @block_stack.pop
end

#pop_local_scope ⇒ Object 



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# File 'lib/twig/parser.rb', line 272

def pop_local_scope
  @imported_symbols.shift
end

#push_block_stack(name) ⇒ Object 



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# File 'lib/twig/parser.rb', line 304

def push_block_stack(name)
  @block_stack << name
end

#push_local_scope ⇒ Object 



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# File 'lib/twig/parser.rb', line 268

def push_local_scope
  @imported_symbols.unshift({})
end

#set_block(name, value) ⇒ Object

Parameters:



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# File 'lib/twig/parser.rb', line 324

def set_block(name, value)
  if @blocks.key?(name)
    raise Error::Syntax.new(
      "The block '#{name}' has already been defined line #{@blocks[name].lineno}.",
      current_token.lineno,
      @blocks[name].source_context
    )
  end

  @blocks[name] = Node::Body.new({ 0 => value }, {}, value.lineno)
end

#set_macro(name, node) ⇒ Object

Parameters:



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# File 'lib/twig/parser.rb', line 318

def set_macro(name, node)
  @macros[name] = node
end

#subparse(test, drop_needle: false) ⇒ Node::Base

Parameters:

  • test (Method, nil)

Returns:



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# File 'lib/twig/parser.rb', line 96

def subparse(test, drop_needle: false)
  lineno = current_token.lineno
  rv = AutoHash.new

  until stream.eof?
    case current_token.type
    when Token::TEXT_TYPE
      token = stream.next
      rv.add(Node::Text.new(token.value, token.lineno))
    when Token::VAR_START_TYPE
      token = stream.next
      expr = parse_expression
      stream.expect(Token::VAR_END_TYPE)

      rv.add(Node::Print.new(expr, token.lineno))
    when Token::BLOCK_START_TYPE
      stream.next
      token = current_token

      unless token.type == Token::NAME_TYPE
        raise Error::Syntax.new('A block must start with a tag name.', token.lineno, stream.source)
      end

      if test&.call(token)
        stream.next if drop_needle
        return rv.values.first if rv.length == 1

        return Node::Nodes.new(rv, lineno)
      end

      subparser = @environment.token_parser(token.value)

      unless subparser
        if test.nil?
          raise Error::Syntax.new("Unknown \"#{token.value}\" tag.", token.lineno, stream.source)
        else
          e = Error::Syntax.new("Unexpected \"#{token.value}\" tag", token.lineno, stream.source)

          if test.respond_to?(:receiver) && (receiver = test.receiver) && receiver.is_a?(Twig::TokenParser::Base)
            e.append_message(
              " (expecting closing tag for the \"#{receiver.tag}\" tag defined near line #{lineno})."
            )
          end

          raise e
        end
      end

      stream.next
      subparser.parser = self
      node = subparser.parse(token)

      raise 'Cannot return nil from TokenParser' unless node

      node.tag = subparser.tag

      rv.add(node)
    else
      raise "Unable to parse token of type #{current_token.type}"
    end
  end

  Node::Nodes.new(rv)
end

#subparse_ignore_unknown_twig_callables(test, drop_needle: false) ⇒ Object 



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# File 'lib/twig/parser.rb', line 161

def subparse_ignore_unknown_twig_callables(test, drop_needle: false)
  previous = @ignore_unknown_twig_callables
  @ignore_unknown_twig_callables = true

  begin
    subparse(test, drop_needle:)
  ensure
    @ignore_unknown_twig_callables = previous
  end
end

#test(line) ⇒ TwigTest

Parameters:

  • line (Integer)

Returns:



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# File 'lib/twig/parser.rb', line 229

def test(line)
  name = stream.expect(Token::NAME_TYPE).value

  if stream.test(Token::NAME_TYPE)
    # try 2 word tests
    name = "#{name} #{current_token.value}"

    if (test = environment.test(name))
      stream.next
    end
  else
    test = environment.test(name)
  end

  if test.nil? && ignore_unknown_twig_callables?
    test = TwigTest.new(name, -> {})
  end

  unless test
    raise Error::Syntax.new("Unknown #{name} test.", line, stream.source)
  end

  test
end