# Class: Haml::Parser

Inherits:
  Object
  - Object
  - Haml::Parser
  show all

Includes:
  Util

Defined in:
  lib/haml/parser.rb

## Defined Under Namespace

Classes: AttributeMerger=Object.new, DynamicAttributes

## Instance Attribute Summary collapse

- #root readonly

  Returns the value of attribute root.

## Instance Method Summary collapse

- #call(template)
- #compute_tabs(line)
- #initialize(options) ⇒ Parser constructor

  A new instance of Parser.

### Methods included from Util

#check_encoding, #check_haml_encoding, #contains_interpolation?, escape_html_safe, #handle_interpolation, #human_indentation, #inspect_obj, #rails_xss_safe?, #silence_warnings, #unescape_interpolation

## Constructor Details

### #initialize(options) ⇒ `Parser`

Returns a new instance of Parser.

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    # File 'lib/haml/parser.rb', line 99

    def initialize(options)
      @options = ParserOptions.new(options)
      # Record the indent levels of "if" statements to validate the subsequent
      # elsif and else statements are indented at the appropriate level.
      @script_level_stack = []
      @template_index     = 0
      @template_tabs      = 0
      # When used in Haml::Engine, which gives options[:generator] to every filter
      # in the engine, including Haml::Parser, we don't want to throw exceptions.
      # However, when Haml::Parser is used as a library, we want to throw exceptions.
      @raise_error = !options.key?(:generator)
    end

## Instance Attribute Details

### #root (readonly)

Returns the value of attribute root.

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    # File 'lib/haml/parser.rb', line 12

    def root
      @root
    end

## Instance Method Details

### #call(template)

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    # File 'lib/haml/parser.rb', line 112

    def call(template)
      template = Haml::Util.check_haml_encoding(template) do |msg, line|
        raise Haml::Error.new(msg, line)
      end

      match = template.rstrip.scan(/(([ \t]+)?(.*?))(?:\Z|\r\n|\r|\n)/m)
      # discard the last match which is always blank
      match.pop
      @template = match.each_with_index.map do |(full, whitespace, text), index|
        Line.new(whitespace, text.rstrip, full, index, self, false)
      end
      # Append special end-of-document marker
      @template << Line.new(nil, '-#', '-#', @template.size, self, true)

      @root = @parent = ParseNode.new(:root)
      @flat = false
      @filter_buffer = nil
      @indentation = nil
      @line = next_line

      raise SyntaxError.new(Error.message(:indenting_at_start), @line.index) if @line.tabs != 0

      loop do
        next_line

        process_indent(@line) unless @line.text.empty?

        if flat?
          text = @line.full.dup
          text = "" unless text.gsub!(/^#{@flat_spaces}/, '')
          @filter_buffer << "#{text}\n"
          @line = @next_line
          next
        end

        @tab_up = nil
        process_line(@line) unless @line.text.empty?
        if block_opened? || @tab_up
          @template_tabs += 1
          @parent = @parent.children.last
        end

        if !flat? && @next_line.tabs - @line.tabs > 1
          raise SyntaxError.new(Error.message(:deeper_indenting, @next_line.tabs - @line.tabs), @next_line.index)
        end

        @line = @next_line
      end
      # Close all the open tags
      close until @parent.type == :root
      @root
    rescue Haml::Error => e
      e.backtrace.unshift "#{@options.filename}:#{(e.line ? e.line + 1 : @line.index + 1) + @options.line - 1}"
      raise if @raise_error
      error_with_lineno(e)
    end

### #compute_tabs(line)

Raises:

- (`SyntaxError`)

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    # File 'lib/haml/parser.rb', line 169

    def compute_tabs(line)
      return 0 if line.text.empty? || !line.whitespace

      if @indentation.nil?
        @indentation = line.whitespace

        if @indentation.include?(?\s) && @indentation.include?(?\t)
          raise SyntaxError.new(Error.message(:cant_use_tabs_and_spaces), line.index)
        end

        @flat_spaces = @indentation * (@template_tabs+1) if flat?
        return 1
      end

      tabs = line.whitespace.length / @indentation.length
      return tabs if line.whitespace == @indentation * tabs
      return @template_tabs + 1 if flat? && line.whitespace =~ /^#{@flat_spaces}/

      message = Error.message(:inconsistent_indentation,
        human_indentation(line.whitespace),
        human_indentation(@indentation)
      )
      raise SyntaxError.new(message, line.index)
    end