Function ToGNString

tools/gypi_to_gn.py:109–207

Returns a stringified GN equivalent of a Python value. Args: value: The Python value to convert. pretty: Whether to pretty print. If true, then non-empty lists are rendered recursively with one item per line, with indents. Otherwise lists are rendered without new line. R

(value, pretty=False)

# This function is copied from build/gn_helpers.py in Chromium.
def ToGNString(value, pretty=False):
  """Returns a stringified GN equivalent of a Python value.

  Args:
    value: The Python value to convert.
    pretty: Whether to pretty print. If true, then non-empty lists are rendered
        recursively with one item per line, with indents. Otherwise lists are
        rendered without new line.
  Returns:
    The stringified GN equivalent to |value|.

  Raises:
    ValueError: |value| cannot be printed to GN.
  """

  # Emits all output tokens without intervening whitespaces.
  def GenerateTokens(v, level):
    if isinstance(v, str):
      yield '"' + ''.join(TranslateToGnChars(v)) + '"'

    elif isinstance(v, bool):
      yield 'true' if v else 'false'

    elif isinstance(v, int):
      yield str(v)

    elif isinstance(v, list):
      yield '['
      for i, item in enumerate(v):
        if i > 0:
          yield ','
        for tok in GenerateTokens(item, level + 1):
          yield tok
      yield ']'

    elif isinstance(v, dict):
      if level > 0:
        yield '{'
      for key in sorted(v):
        if not isinstance(key, str):
          raise ValueError('Dictionary key is not a string.')
        if not key or key[0].isdigit() or not key.replace('_', '').isalnum():
          raise ValueError('Dictionary key is not a valid GN identifier.')
        yield key  # No quotations.
        yield '='
        for tok in GenerateTokens(v[key], level + 1):
          yield tok
      if level > 0:
        yield '}'

    else:  # Not supporting float: Add only when needed.
      raise ValueError('Unsupported type when printing to GN.')

  can_start = lambda tok: tok and tok not in ',}]='
  can_end = lambda tok: tok and tok not in ',{[='

  # Adds whitespaces, trying to keep everything (except dicts) in 1 line.
  def PlainGlue(gen):