618 lines
17 KiB
Python
618 lines
17 KiB
Python
"Usage: unparse.py <path to source file>"
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import sys
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import ast
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import tokenize
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import io
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import os
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# Large float and imaginary literals get turned into infinities in the AST.
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# We unparse those infinities to INFSTR.
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INFSTR = "1e" + repr(sys.float_info.max_10_exp + 1)
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def interleave(inter, f, seq):
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"""Call f on each item in seq, calling inter() in between.
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"""
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seq = iter(seq)
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try:
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f(next(seq))
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except StopIteration:
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pass
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else:
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for x in seq:
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inter()
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f(x)
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class Unparser:
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"""Methods in this class recursively traverse an AST and
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output source code for the abstract syntax; original formatting
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is disregarded. """
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def __init__(self, tree, file = sys.stdout):
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"""Unparser(tree, file=sys.stdout) -> None.
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Print the source for tree to file."""
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self.f = file
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self._indent = 0
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self.dispatch(tree)
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print("", file=self.f)
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self.f.flush()
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def fill(self, text = ""):
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"Indent a piece of text, according to the current indentation level"
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self.f.write("\n"+" "*self._indent + text)
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def write(self, text):
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"Append a piece of text to the current line."
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self.f.write(text)
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def enter(self):
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"Print ':', and increase the indentation."
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self.write(":")
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self._indent += 1
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def leave(self):
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"Decrease the indentation level."
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self._indent -= 1
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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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for t in tree:
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self.dispatch(t)
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return
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meth = getattr(self, "_"+tree.__class__.__name__)
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meth(tree)
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############### Unparsing methods ######################
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# There should be one method per concrete grammar type #
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# Constructors should be grouped by sum type. Ideally, #
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# this would follow the order in the grammar, but #
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# currently doesn't. #
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########################################################
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def _Module(self, tree):
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for stmt in tree.body:
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self.dispatch(stmt)
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# stmt
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def _Expr(self, tree):
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self.fill()
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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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interleave(lambda: self.write(", "), self.dispatch, t.names)
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def _ImportFrom(self, t):
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self.fill("from ")
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self.write("." * t.level)
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if t.module:
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self.write(t.module)
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self.write(" import ")
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interleave(lambda: self.write(", "), self.dispatch, t.names)
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def _Assign(self, t):
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self.fill()
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for target in t.targets:
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self.dispatch(target)
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self.write(" = ")
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self.dispatch(t.value)
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def _AugAssign(self, t):
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self.fill()
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self.dispatch(t.target)
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self.write(" "+self.binop[t.op.__class__.__name__]+"= ")
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self.dispatch(t.value)
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def _Return(self, t):
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self.fill("return")
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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 _Pass(self, t):
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self.fill("pass")
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def _Break(self, t):
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self.fill("break")
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def _Continue(self, t):
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self.fill("continue")
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def _Delete(self, t):
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self.fill("del ")
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interleave(lambda: self.write(", "), self.dispatch, t.targets)
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def _Assert(self, t):
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self.fill("assert ")
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self.dispatch(t.test)
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if t.msg:
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self.write(", ")
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self.dispatch(t.msg)
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def _Global(self, t):
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self.fill("global ")
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interleave(lambda: self.write(", "), self.write, t.names)
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def _Nonlocal(self, t):
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self.fill("nonlocal ")
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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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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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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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def _Raise(self, t):
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self.fill("raise")
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if not t.exc:
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assert not t.cause
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return
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self.write(" ")
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self.dispatch(t.exc)
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if t.cause:
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self.write(" from ")
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self.dispatch(t.cause)
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def _Try(self, t):
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self.fill("try")
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self.enter()
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self.dispatch(t.body)
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self.leave()
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for ex in t.handlers:
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self.dispatch(ex)
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if t.orelse:
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self.fill("else")
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self.enter()
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self.dispatch(t.orelse)
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self.leave()
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if t.finalbody:
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self.fill("finally")
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self.enter()
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self.dispatch(t.finalbody)
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self.leave()
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def _ExceptHandler(self, t):
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self.fill("except")
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if t.type:
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self.write(" ")
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self.dispatch(t.type)
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if t.name:
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self.write(" as ")
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self.write(t.name)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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def _ClassDef(self, t):
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self.write("\n")
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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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self.fill("class "+t.name)
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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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self.write(")")
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self.enter()
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self.dispatch(t.body)
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self.leave()
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def _FunctionDef(self, t):
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self.__FunctionDef_helper(t, "def")
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def _AsyncFunctionDef(self, t):
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self.__FunctionDef_helper(t, "async def")
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def __FunctionDef_helper(self, t, fill_suffix):
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self.write("\n")
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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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self.fill(def_str)
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self.dispatch(t.args)
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self.write(")")
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if t.returns:
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self.write(" -> ")
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self.dispatch(t.returns)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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def _For(self, t):
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self.__For_helper("for ", t)
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def _AsyncFor(self, t):
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self.__For_helper("async for ", t)
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def __For_helper(self, fill, t):
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self.fill(fill)
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self.dispatch(t.target)
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self.write(" in ")
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self.dispatch(t.iter)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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if t.orelse:
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self.fill("else")
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self.enter()
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self.dispatch(t.orelse)
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self.leave()
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def _If(self, t):
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self.fill("if ")
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self.dispatch(t.test)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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# collapse nested ifs into equivalent elifs.
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while (t.orelse and len(t.orelse) == 1 and
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isinstance(t.orelse[0], ast.If)):
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t = t.orelse[0]
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self.fill("elif ")
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self.dispatch(t.test)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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# final else
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if t.orelse:
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self.fill("else")
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self.enter()
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self.dispatch(t.orelse)
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self.leave()
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def _While(self, t):
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self.fill("while ")
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self.dispatch(t.test)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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if t.orelse:
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self.fill("else")
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self.enter()
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self.dispatch(t.orelse)
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self.leave()
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def _With(self, t):
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self.fill("with ")
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interleave(lambda: self.write(", "), self.dispatch, t.items)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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def _AsyncWith(self, t):
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self.fill("async with ")
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interleave(lambda: self.write(", "), self.dispatch, t.items)
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self.enter()
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self.dispatch(t.body)
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self.leave()
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# expr
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def _Bytes(self, t):
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self.write(repr(t.s))
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def _Str(self, tree):
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self.write(repr(tree.s))
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def _Name(self, t):
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self.write(t.id)
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def _NameConstant(self, t):
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self.write(repr(t.value))
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def _Num(self, t):
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# Substitute overflowing decimal literal for AST infinities.
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self.write(repr(t.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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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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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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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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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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def _comprehension(self, t):
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self.write(" for ")
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self.dispatch(t.target)
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self.write(" in ")
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self.dispatch(t.iter)
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for if_clause in t.ifs:
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self.write(" if ")
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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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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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def _Dict(self, t):
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self.write("{")
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def write_pair(pair):
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(k, v) = pair
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self.dispatch(k)
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self.write(": ")
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self.dispatch(v)
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interleave(lambda: self.write(", "), write_pair, zip(t.keys, t.values))
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self.write("}")
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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
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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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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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self.write(" ")
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self.dispatch(t.operand)
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self.write(")")
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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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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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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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def _Attribute(self,t):
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self.dispatch(t.value)
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# Special case: 3.__abs__() is a syntax error, so if t.value
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# is an integer literal then we need to either parenthesize
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# it or add an extra space to get 3 .__abs__().
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if isinstance(t.value, ast.Num) and isinstance(t.value.n, int):
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self.write(" ")
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self.write(".")
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self.write(t.attr)
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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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for e in t.args:
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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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self.write(")")
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def _Subscript(self, t):
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self.dispatch(t.value)
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self.write("[")
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self.dispatch(t.slice)
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self.write("]")
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def _Starred(self, t):
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self.write("*")
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self.dispatch(t.value)
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# slice
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def _Ellipsis(self, t):
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self.write("...")
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def _Index(self, t):
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self.dispatch(t.value)
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def _Slice(self, t):
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if t.lower:
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self.dispatch(t.lower)
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self.write(":")
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if t.upper:
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self.dispatch(t.upper)
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if t.step:
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self.write(":")
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self.dispatch(t.step)
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def _ExtSlice(self, t):
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interleave(lambda: self.write(', '), self.dispatch, t.dims)
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# argument
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def _arg(self, t):
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self.write(t.arg)
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if t.annotation:
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self.write(": ")
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self.dispatch(t.annotation)
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# others
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def _arguments(self, t):
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first = True
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# normal arguments
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defaults = [None] * (len(t.args) - len(t.defaults)) + t.defaults
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for a, d in zip(t.args, defaults):
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if first:first = False
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else: self.write(", ")
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self.dispatch(a)
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if d:
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self.write("=")
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self.dispatch(d)
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# varargs, or bare '*' if no varargs but keyword-only arguments present
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if t.vararg or t.kwonlyargs:
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if first:first = False
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else: self.write(", ")
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self.write("*")
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if t.vararg:
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self.write(t.vararg.arg)
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if t.vararg.annotation:
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self.write(": ")
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self.dispatch(t.vararg.annotation)
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# keyword-only arguments
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if t.kwonlyargs:
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for a, d in zip(t.kwonlyargs, t.kw_defaults):
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if first:first = False
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else: self.write(", ")
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self.dispatch(a),
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if d:
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self.write("=")
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self.dispatch(d)
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# kwargs
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if t.kwarg:
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if first:first = False
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else: self.write(", ")
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self.write("**"+t.kwarg.arg)
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if t.kwarg.annotation:
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self.write(": ")
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self.dispatch(t.kwarg.annotation)
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def _keyword(self, t):
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if t.arg is None:
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self.write("**")
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else:
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self.write(t.arg)
|
|
self.write("=")
|
|
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(")")
|
|
|
|
def _alias(self, t):
|
|
self.write(t.name)
|
|
if t.asname:
|
|
self.write(" as "+t.asname)
|
|
|
|
def _withitem(self, t):
|
|
self.dispatch(t.context_expr)
|
|
if t.optional_vars:
|
|
self.write(" as ")
|
|
self.dispatch(t.optional_vars)
|
|
|
|
def roundtrip(filename, output=sys.stdout):
|
|
with open(filename, "rb") as pyfile:
|
|
encoding = tokenize.detect_encoding(pyfile.readline)[0]
|
|
with open(filename, "r", encoding=encoding) as pyfile:
|
|
source = pyfile.read()
|
|
tree = compile(source, filename, "exec", ast.PyCF_ONLY_AST)
|
|
Unparser(tree, output)
|
|
|
|
|
|
|
|
def testdir(a):
|
|
try:
|
|
names = [n for n in os.listdir(a) if n.endswith('.py')]
|
|
except OSError:
|
|
print("Directory not readable: %s" % a, file=sys.stderr)
|
|
else:
|
|
for n in names:
|
|
fullname = os.path.join(a, n)
|
|
if os.path.isfile(fullname):
|
|
output = io.StringIO()
|
|
print('Testing %s' % fullname)
|
|
try:
|
|
roundtrip(fullname, output)
|
|
except Exception as e:
|
|
print(' Failed to compile, exception is %s' % repr(e))
|
|
elif os.path.isdir(fullname):
|
|
testdir(fullname)
|
|
|
|
def main(args):
|
|
if args[0] == '--testdir':
|
|
for a in args[1:]:
|
|
testdir(a)
|
|
else:
|
|
for a in args:
|
|
roundtrip(a)
|
|
|
|
if __name__=='__main__':
|
|
main(sys.argv[1:])
|