def preprocess_cell(self, cell: NotebookNode, resources, index):
if cell.cell_type == 'code':
for match in re.finditer(r'^%{1,2}(?P<magic>[^ \n\t]*) (?P<parameters>.*)$', cell.source):
magic = match.group('magic')
parameters = match.group('parameters').split()
resources['magics'][magic] = parameters
cell.source = cell.source[:match.start()] + cell.source[match.end() + 1:]
return cell, resources
def blacken_code(cell: NotebookNode, resources: dict,
index: int) -> Tuple[NotebookNode, dict]:
"""Format python source code with black (see https://black.readthedocs.io)."""
try:
import black
except ImportError:
raise ImportError(
"black not installed: see https://black.readthedocs.io")
if cell.get("cell_type", None) != "code":
return cell, resources
# TODO use metadata to set target versions and whether to raise on exceptions
# i.e. black.FileMode(target_versions, {black.TargetVersion.PY36})
try:
cell.source = black.format_str(cell.source, mode=black.FileMode())
except (SyntaxError, black.InvalidInput):
logger.debug(f"cell {index} could not be formatted by black.")
# code cells don't require a trailing new line
cell.source = cell.source.rstrip()
return cell, resources
