Class: Antlers::Lexer

Inherits:
Object
  • Object
show all
Defined in:
lib/antlers/lexer.rb

Instance Method Summary collapse

Constructor Details

#initialize(lexeme_types:) ⇒ Lexer

Returns a new instance of Lexer.



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# File 'lib/antlers/lexer.rb', line 9

def initialize(lexeme_types:)
  @lexeme_types = lexeme_types.to_a
  @var_lexeme = @lexeme_types.find { it == VarLexeme }

  @delimiters = ['<{', '}>']
  @delimiters = [*@delimiters, '{', '}'] if @var_lexeme

  @keywords = @lexeme_types.flat_map { |lexeme| lexeme.const_get(:KEYWORDS) }
  @cursor = 0
end

Instance Method Details

#parse(template:) ⇒ Object 



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# File 'lib/antlers/lexer.rb', line 20

def parse(template:)
  @cursor = 0
  sequence = []

  # Split on delimiters and retain capture groups.
  segments = template.split(/(#{Regexp.union(@delimiters)})/).map(&:strip)

  until segments[@cursor].nil?
    if (segment = antlers_segment(segments:))
      sequence << antlers_lexeme(segment:, segments:)
      # Skipping: ['{', 'expression', '}']
      # Skipping: ['<{', 'name + props + keywords', '}>']
      @cursor += 3
    else
      segment = segments[@cursor]
      sequence << segment unless segment.empty?
      @cursor += 1
    end
  end

  sequence
end