unparser: refactor delimiting with context managers in ast.unparse
Backport of 4b3b1226e8
pull/28346/head
Todd Gamblin
Greg Becker
parent
5847eb1e65
commit
afb358313a
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@ -13,6 +13,7 @@ from six import StringIO
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# TODO: if we require Python 3.7, use its `nullcontext()`
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@contextmanager
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def nullcontext():
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yield
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@ -101,6 +102,21 @@ class Unparser:
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def block(self):
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return self._Block(self)
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@contextmanager
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def delimit(self, start, end):
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"""A context manager for preparing the source for expressions. It adds
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*start* to the buffer and enters, after exit it adds *end*."""
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self.write(start)
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yield
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self.write(end)
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def delimit_if(self, start, end, condition):
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if condition:
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return self.delimit(start, end)
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else:
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return nullcontext()
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def dispatch(self, tree):
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"Dispatcher function, dispatching tree type T to method _T."
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if isinstance(tree, list):
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@ -135,11 +151,10 @@ class Unparser:
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self.dispatch(tree.value)
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def _NamedExpr(self, tree):
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self.write("(")
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self.dispatch(tree.target)
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self.write(" := ")
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self.dispatch(tree.value)
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self.write(")")
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with self.delimit("(", ")"):
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self.dispatch(tree.target)
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self.write(" := ")
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self.dispatch(tree.value)
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def _Import(self, t):
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self.fill("import ")
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@ -172,11 +187,9 @@ class Unparser:
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def _AnnAssign(self, t):
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self.fill()
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if not t.simple and isinstance(t.target, ast.Name):
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self.write('(')
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self.dispatch(t.target)
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if not t.simple and isinstance(t.target, ast.Name):
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self.write(')')
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with self.delimit_if(
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"(", ")", not node.simple and isinstance(t.target, ast.Name)):
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self.dispatch(t.target)
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self.write(": ")
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self.dispatch(t.annotation)
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if t.value:
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@ -250,28 +263,25 @@ class Unparser:
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interleave(lambda: self.write(", "), self.write, t.names)
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def _Await(self, t):
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self.write("(")
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self.write("await")
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if t.value:
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self.write(" ")
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self.dispatch(t.value)
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self.write(")")
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with self.delimit("(", ")"):
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self.write("await")
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if t.value:
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self.write(" ")
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self.dispatch(t.value)
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def _Yield(self, t):
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self.write("(")
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self.write("yield")
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if t.value:
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self.write(" ")
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self.dispatch(t.value)
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self.write(")")
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with self.delimit("(", ")"):
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self.write("yield")
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if t.value:
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self.write(" ")
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self.dispatch(t.value)
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def _YieldFrom(self, t):
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self.write("(")
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self.write("yield from")
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if t.value:
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self.write(" ")
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self.dispatch(t.value)
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self.write(")")
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with self.delimit("(", ")"):
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self.write("yield from")
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if t.value:
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self.write(" ")
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self.dispatch(t.value)
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def _Raise(self, t):
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self.fill("raise")
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@ -356,35 +366,33 @@ class Unparser:
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self.dispatch(deco)
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self.fill("class "+t.name)
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if six.PY3:
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self.write("(")
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comma = False
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for e in t.bases:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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for e in t.keywords:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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if sys.version_info[:2] < (3, 5):
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if t.starargs:
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with self.delimit("(", ")"):
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comma = False
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for e in t.bases:
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if comma: self.write(", ")
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else: comma = True
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self.write("*")
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self.dispatch(t.starargs)
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if t.kwargs:
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self.dispatch(e)
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for e in t.keywords:
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if comma: self.write(", ")
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else: comma = True
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self.write("**")
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self.dispatch(t.kwargs)
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self.write(")")
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self.dispatch(e)
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if sys.version_info[:2] < (3, 5):
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if t.starargs:
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if comma: self.write(", ")
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else: comma = True
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self.write("*")
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self.dispatch(t.starargs)
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if t.kwargs:
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if comma: self.write(", ")
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else: comma = True
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self.write("**")
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self.dispatch(t.kwargs)
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elif t.bases:
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self.write("(")
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with self.delimit("(", ")"):
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for a in t.bases[:-1]:
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self.dispatch(a)
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self.write(", ")
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self.dispatch(t.bases[-1])
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self.write(")")
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with self.block():
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self.dispatch(t.body)
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@ -399,10 +407,10 @@ class Unparser:
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for deco in t.decorator_list:
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self.fill("@")
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self.dispatch(deco)
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def_str = fill_suffix+" "+t.name + "("
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def_str = fill_suffix + " " + t.name
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self.fill(def_str)
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self.dispatch(t.args)
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self.write(")")
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with self.delimit("(", ")"):
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self.dispatch(t.args)
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if getattr(t, "returns", False):
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self.write(" -> ")
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self.dispatch(t.returns)
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@ -574,13 +582,12 @@ class Unparser:
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def _Constant(self, t):
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value = t.value
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if isinstance(value, tuple):
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self.write("(")
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if len(value) == 1:
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self._write_constant(value[0])
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self.write(",")
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else:
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interleave(lambda: self.write(", "), self._write_constant, value)
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self.write(")")
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with self.delimit("(", ")"):
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if len(value) == 1:
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self._write_constant(value[0])
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self.write(",")
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else:
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interleave(lambda: self.write(", "), self._write_constant, value)
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elif value is Ellipsis: # instead of `...` for Py2 compatibility
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self.write("...")
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else:
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@ -594,49 +601,41 @@ class Unparser:
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self.write(repr_n.replace("inf", INFSTR))
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else:
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# Parenthesize negative numbers, to avoid turning (-1)**2 into -1**2.
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if repr_n.startswith("-"):
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self.write("(")
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if "inf" in repr_n and repr_n.endswith("*j"):
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repr_n = repr_n.replace("*j", "j")
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# Substitute overflowing decimal literal for AST infinities.
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self.write(repr_n.replace("inf", INFSTR))
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if repr_n.startswith("-"):
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self.write(")")
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with self.delimit_if("(", ")", repr_n.startswith("-")):
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if "inf" in repr_n and repr_n.endswith("*j"):
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repr_n = repr_n.replace("*j", "j")
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# Substitute overflowing decimal literal for AST infinities.
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self.write(repr_n.replace("inf", INFSTR))
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def _List(self, t):
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self.write("[")
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interleave(lambda: self.write(", "), self.dispatch, t.elts)
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self.write("]")
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with self.delimit("[", "]"):
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interleave(lambda: self.write(", "), self.dispatch, t.elts)
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def _ListComp(self, t):
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self.write("[")
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self.dispatch(t.elt)
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for gen in t.generators:
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self.dispatch(gen)
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self.write("]")
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with self.delimit("[", "]"):
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self.dispatch(t.elt)
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for gen in t.generators:
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self.dispatch(gen)
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def _GeneratorExp(self, t):
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self.write("(")
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self.dispatch(t.elt)
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for gen in t.generators:
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self.dispatch(gen)
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self.write(")")
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with self.delimit("(", ")"):
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self.dispatch(t.elt)
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for gen in t.generators:
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self.dispatch(gen)
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def _SetComp(self, t):
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self.write("{")
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self.dispatch(t.elt)
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for gen in t.generators:
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self.dispatch(gen)
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self.write("}")
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with self.delimit("{", "}"):
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self.dispatch(t.elt)
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for gen in t.generators:
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self.dispatch(gen)
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def _DictComp(self, t):
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self.write("{")
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self.dispatch(t.key)
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self.write(": ")
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self.dispatch(t.value)
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for gen in t.generators:
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self.dispatch(gen)
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self.write("}")
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with self.delimit("{", "}"):
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self.dispatch(t.key)
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self.write(": ")
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self.dispatch(t.value)
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for gen in t.generators:
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self.dispatch(gen)
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def _comprehension(self, t):
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if getattr(t, 'is_async', False):
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@ -651,22 +650,19 @@ class Unparser:
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self.dispatch(if_clause)
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def _IfExp(self, t):
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self.write("(")
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self.dispatch(t.body)
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self.write(" if ")
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self.dispatch(t.test)
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self.write(" else ")
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self.dispatch(t.orelse)
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self.write(")")
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with self.delimit("(", ")"):
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self.dispatch(t.body)
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self.write(" if ")
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self.dispatch(t.test)
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self.write(" else ")
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self.dispatch(t.orelse)
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def _Set(self, t):
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assert(t.elts) # should be at least one element
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self.write("{")
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interleave(lambda: self.write(", "), self.dispatch, t.elts)
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self.write("}")
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with self.delimit("{", "}"):
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interleave(lambda: self.write(", "), self.dispatch, t.elts)
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def _Dict(self, t):
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self.write("{")
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def write_key_value_pair(k, v):
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self.dispatch(k)
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self.write(": ")
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@ -681,64 +677,59 @@ class Unparser:
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self.dispatch(v)
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else:
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write_key_value_pair(k, v)
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interleave(lambda: self.write(", "), write_item, zip(t.keys, t.values))
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self.write("}")
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with self.delimit("{", "}"):
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interleave(lambda: self.write(", "), write_item, zip(t.keys, t.values))
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def _Tuple(self, t):
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self.write("(")
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if len(t.elts) == 1:
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elt = t.elts[0]
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self.dispatch(elt)
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self.write(",")
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else:
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interleave(lambda: self.write(", "), self.dispatch, t.elts)
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self.write(")")
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with self.delimit("(", ")"):
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if len(t.elts) == 1:
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elt = t.elts[0]
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self.dispatch(elt)
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self.write(",")
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else:
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interleave(lambda: self.write(", "), self.dispatch, t.elts)
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unop = {"Invert":"~", "Not": "not", "UAdd":"+", "USub":"-"}
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def _UnaryOp(self, t):
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self.write("(")
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self.write(self.unop[t.op.__class__.__name__])
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if not self._py_ver_consistent:
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self.write(" ")
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if six.PY2 and isinstance(t.op, ast.USub) and isinstance(t.operand, ast.Num):
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# If we're applying unary minus to a number, parenthesize the number.
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# This is necessary: -2147483648 is different from -(2147483648) on
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# a 32-bit machine (the first is an int, the second a long), and
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# -7j is different from -(7j). (The first has real part 0.0, the second
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# has real part -0.0.)
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self.write("(")
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self.dispatch(t.operand)
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self.write(")")
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else:
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self.dispatch(t.operand)
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self.write(")")
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with self.delimit("(", ")"):
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self.write(self.unop[t.op.__class__.__name__])
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if not self._py_ver_consistent:
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self.write(" ")
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if six.PY2 and isinstance(t.op, ast.USub) and isinstance(t.operand, ast.Num):
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# If we're applying unary minus to a number, parenthesize the number.
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# This is necessary: -2147483648 is different from -(2147483648) on
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# a 32-bit machine (the first is an int, the second a long), and
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# -7j is different from -(7j). (The first has real part 0.0, the second
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# has real part -0.0.)
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with self.delimit("(", ")"):
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self.dispatch(t.operand)
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else:
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self.dispatch(t.operand)
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binop = { "Add":"+", "Sub":"-", "Mult":"*", "MatMult":"@", "Div":"/", "Mod":"%",
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"LShift":"<<", "RShift":">>", "BitOr":"|", "BitXor":"^", "BitAnd":"&",
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"FloorDiv":"//", "Pow": "**"}
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def _BinOp(self, t):
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self.write("(")
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self.dispatch(t.left)
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self.write(" " + self.binop[t.op.__class__.__name__] + " ")
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self.dispatch(t.right)
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self.write(")")
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with self.delimit("(", ")"):
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self.dispatch(t.left)
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self.write(" " + self.binop[t.op.__class__.__name__] + " ")
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self.dispatch(t.right)
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cmpops = {"Eq":"==", "NotEq":"!=", "Lt":"<", "LtE":"<=", "Gt":">", "GtE":">=",
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"Is":"is", "IsNot":"is not", "In":"in", "NotIn":"not in"}
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def _Compare(self, t):
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self.write("(")
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self.dispatch(t.left)
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for o, e in zip(t.ops, t.comparators):
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self.write(" " + self.cmpops[o.__class__.__name__] + " ")
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self.dispatch(e)
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self.write(")")
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with self.delimit("(", ")"):
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self.dispatch(t.left)
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for o, e in zip(t.ops, t.comparators):
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self.write(" " + self.cmpops[o.__class__.__name__] + " ")
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self.dispatch(e)
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boolops = {ast.And: 'and', ast.Or: 'or'}
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def _BoolOp(self, t):
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self.write("(")
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s = " %s " % self.boolops[t.op.__class__]
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interleave(lambda: self.write(s), self.dispatch, t.values)
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self.write(")")
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with self.delimit("(", ")"):
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s = " %s " % self.boolops[t.op.__class__]
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interleave(lambda: self.write(s), self.dispatch, t.values)
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def _Attribute(self,t):
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self.dispatch(t.value)
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@ -752,55 +743,52 @@ class Unparser:
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def _Call(self, t):
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self.dispatch(t.func)
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self.write("(")
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comma = False
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with self.delimit("(", ")"):
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comma = False
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# move starred arguments last in Python 3.5+, for consistency w/earlier versions
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star_and_kwargs = []
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move_stars_last = sys.version_info[:2] >= (3, 5)
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# starred arguments last in Python 3.5+, for consistency w/earlier versions
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star_and_kwargs = []
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move_stars_last = sys.version_info[:2] >= (3, 5)
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for e in t.args:
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if move_stars_last and isinstance(e, ast.Starred):
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star_and_kwargs.append(e)
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else:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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for e in t.args:
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if move_stars_last and isinstance(e, ast.Starred):
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star_and_kwargs.append(e)
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else:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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for e in t.keywords:
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# starting from Python 3.5 this denotes a kwargs part of the invocation
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if e.arg is None and move_stars_last:
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star_and_kwargs.append(e)
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else:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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for e in t.keywords:
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# starting from Python 3.5 this denotes a kwargs part of the invocation
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if e.arg is None and move_stars_last:
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star_and_kwargs.append(e)
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else:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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if move_stars_last:
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for e in star_and_kwargs:
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if comma: self.write(", ")
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else: comma = True
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self.dispatch(e)
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if move_stars_last:
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for e in star_and_kwargs:
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if comma: self.write(", ")
|
||||
else: comma = True
|
||||
self.dispatch(e)
|
||||
|
||||
if sys.version_info[:2] < (3, 5):
|
||||
if t.starargs:
|
||||
if comma: self.write(", ")
|
||||
else: comma = True
|
||||
self.write("*")
|
||||
self.dispatch(t.starargs)
|
||||
if t.kwargs:
|
||||
if comma: self.write(", ")
|
||||
else: comma = True
|
||||
self.write("**")
|
||||
self.dispatch(t.kwargs)
|
||||
|
||||
self.write(")")
|
||||
if sys.version_info[:2] < (3, 5):
|
||||
if t.starargs:
|
||||
if comma: self.write(", ")
|
||||
else: comma = True
|
||||
self.write("*")
|
||||
self.dispatch(t.starargs)
|
||||
if t.kwargs:
|
||||
if comma: self.write(", ")
|
||||
else: comma = True
|
||||
self.write("**")
|
||||
self.dispatch(t.kwargs)
|
||||
|
||||
def _Subscript(self, t):
|
||||
self.dispatch(t.value)
|
||||
self.write("[")
|
||||
self.dispatch(t.slice)
|
||||
self.write("]")
|
||||
with self.delimit("[", "]"):
|
||||
self.dispatch(t.slice)
|
||||
|
||||
def _Starred(self, t):
|
||||
self.write("*")
|
||||
|
|
@ -902,12 +890,11 @@ class Unparser:
|
|||
self.dispatch(t.value)
|
||||
|
||||
def _Lambda(self, t):
|
||||
self.write("(")
|
||||
self.write("lambda ")
|
||||
self.dispatch(t.args)
|
||||
self.write(": ")
|
||||
self.dispatch(t.body)
|
||||
self.write(")")
|
||||
with self.delimit("(", ")"):
|
||||
self.write("lambda ")
|
||||
self.dispatch(t.args)
|
||||
self.write(": ")
|
||||
self.dispatch(t.body)
|
||||
|
||||
def _alias(self, t):
|
||||
self.write(t.name)
|
||||
|
|
|
|||
Loading…
Reference in New Issue