source: python/vendor/Python-2.7.6/Demo/parser/unparse.py

Last change on this file was 388, checked in by dmik, 11 years ago

python: Update vendor to 2.7.6.
  • Property svn:eol-style set to native
File size: 16.9 KB
Line 
1"Usage: unparse.py <path to source file>"
2import sys
3import ast
4import cStringIO
5import os
6
7# Large float and imaginary literals get turned into infinities in the AST.
8# We unparse those infinities to INFSTR.
9INFSTR = "1e" + repr(sys.float_info.max_10_exp + 1)
10
11def interleave(inter, f, seq):
12 """Call f on each item in seq, calling inter() in between.
13 """
14 seq = iter(seq)
15 try:
16 f(next(seq))
17 except StopIteration:
18 pass
19 else:
20 for x in seq:
21 inter()
22 f(x)
23
24class Unparser:
25 """Methods in this class recursively traverse an AST and
26 output source code for the abstract syntax; original formatting
27 is disregarded. """
28
29 def __init__(self, tree, file = sys.stdout):
30 """Unparser(tree, file=sys.stdout) -> None.
31 Print the source for tree to file."""
32 self.f = file
33 self.future_imports = []
34 self._indent = 0
35 self.dispatch(tree)
36 self.f.write("")
37 self.f.flush()
38
39 def fill(self, text = ""):
40 "Indent a piece of text, according to the current indentation level"
41 self.f.write("\n"+" "*self._indent + text)
42
43 def write(self, text):
44 "Append a piece of text to the current line."
45 self.f.write(text)
46
47 def enter(self):
48 "Print ':', and increase the indentation."
49 self.write(":")
50 self._indent += 1
51
52 def leave(self):
53 "Decrease the indentation level."
54 self._indent -= 1
55
56 def dispatch(self, tree):
57 "Dispatcher function, dispatching tree type T to method _T."
58 if isinstance(tree, list):
59 for t in tree:
60 self.dispatch(t)
61 return
62 meth = getattr(self, "_"+tree.__class__.__name__)
63 meth(tree)
64
65
66 ############### Unparsing methods ######################
67 # There should be one method per concrete grammar type #
68 # Constructors should be grouped by sum type. Ideally, #
69 # this would follow the order in the grammar, but #
70 # currently doesn't. #
71 ########################################################
72
73 def _Module(self, tree):
74 for stmt in tree.body:
75 self.dispatch(stmt)
76
77 # stmt
78 def _Expr(self, tree):
79 self.fill()
80 self.dispatch(tree.value)
81
82 def _Import(self, t):
83 self.fill("import ")
84 interleave(lambda: self.write(", "), self.dispatch, t.names)
85
86 def _ImportFrom(self, t):
87 # A from __future__ import may affect unparsing, so record it.
88 if t.module and t.module == '__future__':
89 self.future_imports.extend(n.name for n in t.names)
90
91 self.fill("from ")
92 self.write("." * t.level)
93 if t.module:
94 self.write(t.module)
95 self.write(" import ")
96 interleave(lambda: self.write(", "), self.dispatch, t.names)
97
98 def _Assign(self, t):
99 self.fill()
100 for target in t.targets:
101 self.dispatch(target)
102 self.write(" = ")
103 self.dispatch(t.value)
104
105 def _AugAssign(self, t):
106 self.fill()
107 self.dispatch(t.target)
108 self.write(" "+self.binop[t.op.__class__.__name__]+"= ")
109 self.dispatch(t.value)
110
111 def _Return(self, t):
112 self.fill("return")
113 if t.value:
114 self.write(" ")
115 self.dispatch(t.value)
116
117 def _Pass(self, t):
118 self.fill("pass")
119
120 def _Break(self, t):
121 self.fill("break")
122
123 def _Continue(self, t):
124 self.fill("continue")
125
126 def _Delete(self, t):
127 self.fill("del ")
128 interleave(lambda: self.write(", "), self.dispatch, t.targets)
129
130 def _Assert(self, t):
131 self.fill("assert ")
132 self.dispatch(t.test)
133 if t.msg:
134 self.write(", ")
135 self.dispatch(t.msg)
136
137 def _Exec(self, t):
138 self.fill("exec ")
139 self.dispatch(t.body)
140 if t.globals:
141 self.write(" in ")
142 self.dispatch(t.globals)
143 if t.locals:
144 self.write(", ")
145 self.dispatch(t.locals)
146
147 def _Print(self, t):
148 self.fill("print ")
149 do_comma = False
150 if t.dest:
151 self.write(">>")
152 self.dispatch(t.dest)
153 do_comma = True
154 for e in t.values:
155 if do_comma:self.write(", ")
156 else:do_comma=True
157 self.dispatch(e)
158 if not t.nl:
159 self.write(",")
160
161 def _Global(self, t):
162 self.fill("global ")
163 interleave(lambda: self.write(", "), self.write, t.names)
164
165 def _Yield(self, t):
166 self.write("(")
167 self.write("yield")
168 if t.value:
169 self.write(" ")
170 self.dispatch(t.value)
171 self.write(")")
172
173 def _Raise(self, t):
174 self.fill('raise ')
175 if t.type:
176 self.dispatch(t.type)
177 if t.inst:
178 self.write(", ")
179 self.dispatch(t.inst)
180 if t.tback:
181 self.write(", ")
182 self.dispatch(t.tback)
183
184 def _TryExcept(self, t):
185 self.fill("try")
186 self.enter()
187 self.dispatch(t.body)
188 self.leave()
189
190 for ex in t.handlers:
191 self.dispatch(ex)
192 if t.orelse:
193 self.fill("else")
194 self.enter()
195 self.dispatch(t.orelse)
196 self.leave()
197
198 def _TryFinally(self, t):
199 if len(t.body) == 1 and isinstance(t.body[0], ast.TryExcept):
200 # try-except-finally
201 self.dispatch(t.body)
202 else:
203 self.fill("try")
204 self.enter()
205 self.dispatch(t.body)
206 self.leave()
207
208 self.fill("finally")
209 self.enter()
210 self.dispatch(t.finalbody)
211 self.leave()
212
213 def _ExceptHandler(self, t):
214 self.fill("except")
215 if t.type:
216 self.write(" ")
217 self.dispatch(t.type)
218 if t.name:
219 self.write(" as ")
220 self.dispatch(t.name)
221 self.enter()
222 self.dispatch(t.body)
223 self.leave()
224
225 def _ClassDef(self, t):
226 self.write("\n")
227 for deco in t.decorator_list:
228 self.fill("@")
229 self.dispatch(deco)
230 self.fill("class "+t.name)
231 if t.bases:
232 self.write("(")
233 for a in t.bases:
234 self.dispatch(a)
235 self.write(", ")
236 self.write(")")
237 self.enter()
238 self.dispatch(t.body)
239 self.leave()
240
241 def _FunctionDef(self, t):
242 self.write("\n")
243 for deco in t.decorator_list:
244 self.fill("@")
245 self.dispatch(deco)
246 self.fill("def "+t.name + "(")
247 self.dispatch(t.args)
248 self.write(")")
249 self.enter()
250 self.dispatch(t.body)
251 self.leave()
252
253 def _For(self, t):
254 self.fill("for ")
255 self.dispatch(t.target)
256 self.write(" in ")
257 self.dispatch(t.iter)
258 self.enter()
259 self.dispatch(t.body)
260 self.leave()
261 if t.orelse:
262 self.fill("else")
263 self.enter()
264 self.dispatch(t.orelse)
265 self.leave()
266
267 def _If(self, t):
268 self.fill("if ")
269 self.dispatch(t.test)
270 self.enter()
271 self.dispatch(t.body)
272 self.leave()
273 # collapse nested ifs into equivalent elifs.
274 while (t.orelse and len(t.orelse) == 1 and
275 isinstance(t.orelse[0], ast.If)):
276 t = t.orelse[0]
277 self.fill("elif ")
278 self.dispatch(t.test)
279 self.enter()
280 self.dispatch(t.body)
281 self.leave()
282 # final else
283 if t.orelse:
284 self.fill("else")
285 self.enter()
286 self.dispatch(t.orelse)
287 self.leave()
288
289 def _While(self, t):
290 self.fill("while ")
291 self.dispatch(t.test)
292 self.enter()
293 self.dispatch(t.body)
294 self.leave()
295 if t.orelse:
296 self.fill("else")
297 self.enter()
298 self.dispatch(t.orelse)
299 self.leave()
300
301 def _With(self, t):
302 self.fill("with ")
303 self.dispatch(t.context_expr)
304 if t.optional_vars:
305 self.write(" as ")
306 self.dispatch(t.optional_vars)
307 self.enter()
308 self.dispatch(t.body)
309 self.leave()
310
311 # expr
312 def _Str(self, tree):
313 # if from __future__ import unicode_literals is in effect,
314 # then we want to output string literals using a 'b' prefix
315 # and unicode literals with no prefix.
316 if "unicode_literals" not in self.future_imports:
317 self.write(repr(tree.s))
318 elif isinstance(tree.s, str):
319 self.write("b" + repr(tree.s))
320 elif isinstance(tree.s, unicode):
321 self.write(repr(tree.s).lstrip("u"))
322 else:
323 assert False, "shouldn't get here"
324
325 def _Name(self, t):
326 self.write(t.id)
327
328 def _Repr(self, t):
329 self.write("`")
330 self.dispatch(t.value)
331 self.write("`")
332
333 def _Num(self, t):
334 repr_n = repr(t.n)
335 # Parenthesize negative numbers, to avoid turning (-1)**2 into -1**2.
336 if repr_n.startswith("-"):
337 self.write("(")
338 # Substitute overflowing decimal literal for AST infinities.
339 self.write(repr_n.replace("inf", INFSTR))
340 if repr_n.startswith("-"):
341 self.write(")")
342
343 def _List(self, t):
344 self.write("[")
345 interleave(lambda: self.write(", "), self.dispatch, t.elts)
346 self.write("]")
347
348 def _ListComp(self, t):
349 self.write("[")
350 self.dispatch(t.elt)
351 for gen in t.generators:
352 self.dispatch(gen)
353 self.write("]")
354
355 def _GeneratorExp(self, t):
356 self.write("(")
357 self.dispatch(t.elt)
358 for gen in t.generators:
359 self.dispatch(gen)
360 self.write(")")
361
362 def _SetComp(self, t):
363 self.write("{")
364 self.dispatch(t.elt)
365 for gen in t.generators:
366 self.dispatch(gen)
367 self.write("}")
368
369 def _DictComp(self, t):
370 self.write("{")
371 self.dispatch(t.key)
372 self.write(": ")
373 self.dispatch(t.value)
374 for gen in t.generators:
375 self.dispatch(gen)
376 self.write("}")
377
378 def _comprehension(self, t):
379 self.write(" for ")
380 self.dispatch(t.target)
381 self.write(" in ")
382 self.dispatch(t.iter)
383 for if_clause in t.ifs:
384 self.write(" if ")
385 self.dispatch(if_clause)
386
387 def _IfExp(self, t):
388 self.write("(")
389 self.dispatch(t.body)
390 self.write(" if ")
391 self.dispatch(t.test)
392 self.write(" else ")
393 self.dispatch(t.orelse)
394 self.write(")")
395
396 def _Set(self, t):
397 assert(t.elts) # should be at least one element
398 self.write("{")
399 interleave(lambda: self.write(", "), self.dispatch, t.elts)
400 self.write("}")
401
402 def _Dict(self, t):
403 self.write("{")
404 def write_pair(pair):
405 (k, v) = pair
406 self.dispatch(k)
407 self.write(": ")
408 self.dispatch(v)
409 interleave(lambda: self.write(", "), write_pair, zip(t.keys, t.values))
410 self.write("}")
411
412 def _Tuple(self, t):
413 self.write("(")
414 if len(t.elts) == 1:
415 (elt,) = t.elts
416 self.dispatch(elt)
417 self.write(",")
418 else:
419 interleave(lambda: self.write(", "), self.dispatch, t.elts)
420 self.write(")")
421
422 unop = {"Invert":"~", "Not": "not", "UAdd":"+", "USub":"-"}
423 def _UnaryOp(self, t):
424 self.write("(")
425 self.write(self.unop[t.op.__class__.__name__])
426 self.write(" ")
427 # If we're applying unary minus to a number, parenthesize the number.
428 # This is necessary: -2147483648 is different from -(2147483648) on
429 # a 32-bit machine (the first is an int, the second a long), and
430 # -7j is different from -(7j). (The first has real part 0.0, the second
431 # has real part -0.0.)
432 if isinstance(t.op, ast.USub) and isinstance(t.operand, ast.Num):
433 self.write("(")
434 self.dispatch(t.operand)
435 self.write(")")
436 else:
437 self.dispatch(t.operand)
438 self.write(")")
439
440 binop = { "Add":"+", "Sub":"-", "Mult":"*", "Div":"/", "Mod":"%",
441 "LShift":"<<", "RShift":">>", "BitOr":"|", "BitXor":"^", "BitAnd":"&",
442 "FloorDiv":"//", "Pow": "**"}
443 def _BinOp(self, t):
444 self.write("(")
445 self.dispatch(t.left)
446 self.write(" " + self.binop[t.op.__class__.__name__] + " ")
447 self.dispatch(t.right)
448 self.write(")")
449
450 cmpops = {"Eq":"==", "NotEq":"!=", "Lt":"<", "LtE":"<=", "Gt":">", "GtE":">=",
451 "Is":"is", "IsNot":"is not", "In":"in", "NotIn":"not in"}
452 def _Compare(self, t):
453 self.write("(")
454 self.dispatch(t.left)
455 for o, e in zip(t.ops, t.comparators):
456 self.write(" " + self.cmpops[o.__class__.__name__] + " ")
457 self.dispatch(e)
458 self.write(")")
459
460 boolops = {ast.And: 'and', ast.Or: 'or'}
461 def _BoolOp(self, t):
462 self.write("(")
463 s = " %s " % self.boolops[t.op.__class__]
464 interleave(lambda: self.write(s), self.dispatch, t.values)
465 self.write(")")
466
467 def _Attribute(self,t):
468 self.dispatch(t.value)
469 # Special case: 3.__abs__() is a syntax error, so if t.value
470 # is an integer literal then we need to either parenthesize
471 # it or add an extra space to get 3 .__abs__().
472 if isinstance(t.value, ast.Num) and isinstance(t.value.n, int):
473 self.write(" ")
474 self.write(".")
475 self.write(t.attr)
476
477 def _Call(self, t):
478 self.dispatch(t.func)
479 self.write("(")
480 comma = False
481 for e in t.args:
482 if comma: self.write(", ")
483 else: comma = True
484 self.dispatch(e)
485 for e in t.keywords:
486 if comma: self.write(", ")
487 else: comma = True
488 self.dispatch(e)
489 if t.starargs:
490 if comma: self.write(", ")
491 else: comma = True
492 self.write("*")
493 self.dispatch(t.starargs)
494 if t.kwargs:
495 if comma: self.write(", ")
496 else: comma = True
497 self.write("**")
498 self.dispatch(t.kwargs)
499 self.write(")")
500
501 def _Subscript(self, t):
502 self.dispatch(t.value)
503 self.write("[")
504 self.dispatch(t.slice)
505 self.write("]")
506
507 # slice
508 def _Ellipsis(self, t):
509 self.write("...")
510
511 def _Index(self, t):
512 self.dispatch(t.value)
513
514 def _Slice(self, t):
515 if t.lower:
516 self.dispatch(t.lower)
517 self.write(":")
518 if t.upper:
519 self.dispatch(t.upper)
520 if t.step:
521 self.write(":")
522 self.dispatch(t.step)
523
524 def _ExtSlice(self, t):
525 interleave(lambda: self.write(', '), self.dispatch, t.dims)
526
527 # others
528 def _arguments(self, t):
529 first = True
530 # normal arguments
531 defaults = [None] * (len(t.args) - len(t.defaults)) + t.defaults
532 for a,d in zip(t.args, defaults):
533 if first:first = False
534 else: self.write(", ")
535 self.dispatch(a),
536 if d:
537 self.write("=")
538 self.dispatch(d)
539
540 # varargs
541 if t.vararg:
542 if first:first = False
543 else: self.write(", ")
544 self.write("*")
545 self.write(t.vararg)
546
547 # kwargs
548 if t.kwarg:
549 if first:first = False
550 else: self.write(", ")
551 self.write("**"+t.kwarg)
552
553 def _keyword(self, t):
554 self.write(t.arg)
555 self.write("=")
556 self.dispatch(t.value)
557
558 def _Lambda(self, t):
559 self.write("(")
560 self.write("lambda ")
561 self.dispatch(t.args)
562 self.write(": ")
563 self.dispatch(t.body)
564 self.write(")")
565
566 def _alias(self, t):
567 self.write(t.name)
568 if t.asname:
569 self.write(" as "+t.asname)
570
571def roundtrip(filename, output=sys.stdout):
572 with open(filename, "r") as pyfile:
573 source = pyfile.read()
574 tree = compile(source, filename, "exec", ast.PyCF_ONLY_AST)
575 Unparser(tree, output)
576
577
578
579def testdir(a):
580 try:
581 names = [n for n in os.listdir(a) if n.endswith('.py')]
582 except OSError:
583 sys.stderr.write("Directory not readable: %s" % a)
584 else:
585 for n in names:
586 fullname = os.path.join(a, n)
587 if os.path.isfile(fullname):
588 output = cStringIO.StringIO()
589 print 'Testing %s' % fullname
590 try:
591 roundtrip(fullname, output)
592 except Exception as e:
593 print ' Failed to compile, exception is %s' % repr(e)
594 elif os.path.isdir(fullname):
595 testdir(fullname)
596
597def main(args):
598 if args[0] == '--testdir':
599 for a in args[1:]:
600 testdir(a)
601 else:
602 for a in args:
603 roundtrip(a)
604
605if __name__=='__main__':
606 main(sys.argv[1:])
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