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