Class: Rng::RncParser

Inherits:
Parslet::Parser
  • Object
show all
Defined in:
lib/rng/rnc_parser.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.convert_to_rng(tree) ⇒ Object

Convert parse tree to RNG XML



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# File 'lib/rng/rnc_parser.rb', line 691

def self.convert_to_rng(tree)
  RncToRngConverter.new.convert(tree)
end

.extract_string(obj) ⇒ Object

Helper method to extract clean string without Parslet position markers



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# File 'lib/rng/rnc_parser.rb', line 10

def self.extract_string(obj)
  if obj.respond_to?(:str)
    # Parslet::Slice - use .str to get clean string
    obj.str
  elsif obj.is_a?(String)
    obj
  else
    obj.to_s
  end
end

.parse(input) ⇒ Object 



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# File 'lib/rng/rnc_parser.rb', line 671

def self.parse(input)
  parser = new
  preprocessed = preprocess_hex_escapes(input.strip)
  tree = parser.parse(preprocessed)

  # Normalize parse tree
  processor = ParseTreeProcessor.new(tree)
  normalized = processor.normalize

  # Convert to RNG XML and Grammar object
  rng_xml = convert_to_rng(normalized.grammar_tree)
  Grammar.from_xml(rng_xml)
end

.parse_file(file_path, base_dir = nil, visited_files = Set.new) ⇒ Object

Class method to parse a file with include resolution



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# File 'lib/rng/rnc_parser.rb', line 597

def self.parse_file(file_path, base_dir = nil, visited_files = Set.new)
  IncludeProcessor.new.parse_file(file_path, base_dir, visited_files)
end

.preprocess_hex_escapes(input) ⇒ Object

Pre-process RNC input to resolve hex escapes (xHHHHHH) outside of string literals. This allows keywords to contain hex escapes (e.g., x65lx00065ment = “element”). String literals keep their hex escapes for the parser to handle, because control characters like xA (newline) are forbidden inside single-line quoted strings and must remain escaped.



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# File 'lib/rng/rnc_parser.rb', line 607

def self.preprocess_hex_escapes(input)
  result = +''
  i = 0
  while i < input.length
    # Triple-quoted strings: copy verbatim
    if input[i, 3] == '"""'
      end_idx = input.index('"""', i + 3)
      end_idx ||= input.length - 3
      result << input[i..(end_idx + 2)]
      i = end_idx + 3
    elsif input[i, 3] == "'''"
      end_idx = input.index("'''", i + 3)
      end_idx ||= input.length - 3
      result << input[i..(end_idx + 2)]
      i = end_idx + 3
    # Single-line double-quoted string: copy verbatim
    elsif input[i] == '"'
      j = i + 1
      while j < input.length && input[j] != '"'
        j += 1 if input[j] == '\\' && j + 1 < input.length # skip escaped char
        j += 1
      end
      result << input[i..j]
      i = j + 1
    # Single-line single-quoted string: copy verbatim
    elsif input[i] == "'"
      j = i + 1
      while j < input.length && input[j] != "'"
        j += 1 if input[j] == '\\' && j + 1 < input.length # skip escaped char
        j += 1
      end
      result << input[i..j]
      i = j + 1
    # Comment: copy verbatim to end of line
    elsif input[i] == '#'
      j = input.index("\n", i) || input.length
      result << input[i...j]
      i = j
    # Hex escape outside string: decode it
    elsif input[i] == '\\' && input[i + 1] == 'x' && input[i + 2] == '{'
      end_brace = input.index('}', i + 3)
      if end_brace
        hex = input[(i + 3)...end_brace]
        if hex.match?(/\A[0-9a-fA-F]{1,6}\z/)
          code_point = hex.to_i(16)
          if code_point <= 0x10FFFF && !code_point.between?(0xD800, 0xDFFF) &&
             code_point >= 0x20 # Reject control characters outside strings
            result << [code_point].pack('U')
            i = end_brace + 1
            next
          end
        end
      end
      # Not a valid hex escape, copy as-is
      result << input[i]
      i += 1
    else
      result << input[i]
      i += 1
    end
  end
  result
end

.to_rnc(schema) ⇒ Object

Convert RNG schema to RNC



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# File 'lib/rng/rnc_parser.rb', line 686

def self.to_rnc(schema)
  RncBuilder.new.build(schema)
end

Instance Method Details

#keyword(kw) ⇒ Object

Match a keyword that may contain hex escapes Hex escapes are resolved in pre-processing, so keywords match literally here But we still need to handle the case where pre-processing didn’t happen



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# File 'lib/rng/rnc_parser.rb', line 49

def keyword(kw)
  str(kw)
end