| """Fixer for function definitions with tuple parameters. |
| |
| def func(((a, b), c), d): |
| ... |
| |
| -> |
| |
| def func(x, d): |
| ((a, b), c) = x |
| ... |
| |
| It will also support lambdas: |
| |
| lambda (x, y): x + y -> lambda t: t[0] + t[1] |
| |
| # The parens are a syntax error in Python 3 |
| lambda (x): x + y -> lambda x: x + y |
| """ |
| # Author: Collin Winter |
| |
| # Local imports |
| from .. import pytree |
| from ..pgen2 import token |
| from .. import fixer_base |
| from ..fixer_util import Assign, Name, Newline, Number, Subscript, syms |
| |
| def is_docstring(stmt): |
| return isinstance(stmt, pytree.Node) and \ |
| stmt.children[0].type == token.STRING |
| |
| class FixTupleParams(fixer_base.BaseFix): |
| PATTERN = """ |
| funcdef< 'def' any parameters< '(' args=any ')' > |
| ['->' any] ':' suite=any+ > |
| | |
| lambda= |
| lambdef< 'lambda' args=vfpdef< '(' inner=any ')' > |
| ':' body=any |
| > |
| """ |
| |
| def transform(self, node, results): |
| if "lambda" in results: |
| return self.transform_lambda(node, results) |
| |
| new_lines = [] |
| suite = results["suite"] |
| args = results["args"] |
| # This crap is so "def foo(...): x = 5; y = 7" is handled correctly. |
| # TODO(cwinter): suite-cleanup |
| if suite[0].children[1].type == token.INDENT: |
| start = 2 |
| indent = suite[0].children[1].value |
| end = Newline() |
| else: |
| start = 0 |
| indent = "; " |
| end = pytree.Leaf(token.INDENT, "") |
| |
| # We need access to self for new_name(), and making this a method |
| # doesn't feel right. Closing over self and new_lines makes the |
| # code below cleaner. |
| def handle_tuple(tuple_arg, add_prefix=False): |
| n = Name(self.new_name()) |
| arg = tuple_arg.clone() |
| arg.prefix = "" |
| stmt = Assign(arg, n.clone()) |
| if add_prefix: |
| n.prefix = " " |
| tuple_arg.replace(n) |
| new_lines.append(pytree.Node(syms.simple_stmt, |
| [stmt, end.clone()])) |
| |
| if args.type == syms.tfpdef: |
| handle_tuple(args) |
| elif args.type == syms.typedargslist: |
| for i, arg in enumerate(args.children): |
| if arg.type == syms.tfpdef: |
| # Without add_prefix, the emitted code is correct, |
| # just ugly. |
| handle_tuple(arg, add_prefix=(i > 0)) |
| |
| if not new_lines: |
| return node |
| |
| # This isn't strictly necessary, but it plays nicely with other fixers. |
| # TODO(cwinter) get rid of this when children becomes a smart list |
| for line in new_lines: |
| line.parent = suite[0] |
| |
| # TODO(cwinter) suite-cleanup |
| after = start |
| if start == 0: |
| new_lines[0].prefix = " " |
| elif is_docstring(suite[0].children[start]): |
| new_lines[0].prefix = indent |
| after = start + 1 |
| |
| for line in new_lines: |
| line.parent = suite[0] |
| suite[0].children[after:after] = new_lines |
| for i in range(after+1, after+len(new_lines)+1): |
| suite[0].children[i].prefix = indent |
| suite[0].changed() |
| |
| def transform_lambda(self, node, results): |
| args = results["args"] |
| body = results["body"] |
| inner = simplify_args(results["inner"]) |
| |
| # Replace lambda ((((x)))): x with lambda x: x |
| if inner.type == token.NAME: |
| inner = inner.clone() |
| inner.prefix = " " |
| args.replace(inner) |
| return |
| |
| params = find_params(args) |
| to_index = map_to_index(params) |
| tup_name = self.new_name(tuple_name(params)) |
| |
| new_param = Name(tup_name, prefix=" ") |
| args.replace(new_param.clone()) |
| for n in body.post_order(): |
| if n.type == token.NAME and n.value in to_index: |
| subscripts = [c.clone() for c in to_index[n.value]] |
| new = pytree.Node(syms.power, |
| [new_param.clone()] + subscripts) |
| new.prefix = n.prefix |
| n.replace(new) |
| |
| |
| ### Helper functions for transform_lambda() |
| |
| def simplify_args(node): |
| if node.type in (syms.vfplist, token.NAME): |
| return node |
| elif node.type == syms.vfpdef: |
| # These look like vfpdef< '(' x ')' > where x is NAME |
| # or another vfpdef instance (leading to recursion). |
| while node.type == syms.vfpdef: |
| node = node.children[1] |
| return node |
| raise RuntimeError("Received unexpected node %s" % node) |
| |
| def find_params(node): |
| if node.type == syms.vfpdef: |
| return find_params(node.children[1]) |
| elif node.type == token.NAME: |
| return node.value |
| return [find_params(c) for c in node.children if c.type != token.COMMA] |
| |
| def map_to_index(param_list, prefix=[], d=None): |
| if d is None: |
| d = {} |
| for i, obj in enumerate(param_list): |
| trailer = [Subscript(Number(i))] |
| if isinstance(obj, list): |
| map_to_index(obj, trailer, d=d) |
| else: |
| d[obj] = prefix + trailer |
| return d |
| |
| def tuple_name(param_list): |
| l = [] |
| for obj in param_list: |
| if isinstance(obj, list): |
| l.append(tuple_name(obj)) |
| else: |
| l.append(obj) |
| return "_".join(l) |