def visit_future(node):
"""Accumulates a set of compiler flags for the compiler __future__ imports.
Returns an instance of FutureFeatures which encapsulates the flags and the
line number of the last valid future import parsed. A downstream parser can
use the latter to detect invalid future imports that appear too late in the
file.
"""
# If this is the module node, do an initial pass through the module body's
# statements to detect future imports and process their directives (i.e.,
# set compiler flags), and detect ones that don't appear at the beginning of
# the file. The only things that can proceed a future statement are other
# future statements and/or a doc string.
assert isinstance(node, ast.Module)
ff = FutureFeatures()
done = False
found_docstring = False
for node in node.body:
if isinstance(node, ast.ImportFrom):
modname = node.module
if modname == '__future__':
if done:
raise util.ParseError(node, late_future)
ff.parser_flags |= import_from_future(node)
ff.future_lineno = node.lineno
else:
done = True
elif isinstance(node, ast.Expr) and not found_docstring:
e = node.value
if not isinstance(e, ast.Str): # pylint: disable=simplifiable-if-statement
done = True
else:
found_docstring = True
else:
done = True
return ff
def _node_not_implemented(self, node): msg = 'node not yet implemented: ' + type(node).__name__ raise util.ParseError(node, msg)
def generic_visit(self, node): msg = 'expression node not yet implemented: ' + type(node).__name__ raise util.ParseError(node, msg)
def visit_Continue(self, node):
if not self.block.loop_stack:
raise util.ParseError(node, "'continue' not in loop")
self._write_py_context(node.lineno)
self.writer.write('goto Label{}'.format(self.block.top_loop().start_label))
def generic_visit(self, node):
msg = 'node not yet implemented: {}'.format(type(node).__name__)
raise util.ParseError(node, msg)
def visit_Continue(self, node):
if not self.block.loop_stack:
raise util.ParseError(node, "'continue' not in loop")
self._write_py_context(node.lineno)
self.writer.write('continue')