/Demo/parser/unparse.py
Python | 518 lines | 508 code | 3 blank | 7 comment | 11 complexity | 1931bab04f70736294ae846c3265878c MD5 | raw file
1"Usage: unparse.py <path to source file>" 2import sys 3import _ast 4import cStringIO 5import os 6 7def interleave(inter, f, seq): 8 """Call f on each item in seq, calling inter() in between. 9 """ 10 seq = iter(seq) 11 try: 12 f(seq.next()) 13 except StopIteration: 14 pass 15 else: 16 for x in seq: 17 inter() 18 f(x) 19 20class Unparser: 21 """Methods in this class recursively traverse an AST and 22 output source code for the abstract syntax; original formatting 23 is disregarged. """ 24 25 def __init__(self, tree, file = sys.stdout): 26 """Unparser(tree, file=sys.stdout) -> None. 27 Print the source for tree to file.""" 28 self.f = file 29 self._indent = 0 30 self.dispatch(tree) 31 print >>self.f,"" 32 self.f.flush() 33 34 def fill(self, text = ""): 35 "Indent a piece of text, according to the current indentation level" 36 self.f.write("\n"+" "*self._indent + text) 37 38 def write(self, text): 39 "Append a piece of text to the current line." 40 self.f.write(text) 41 42 def enter(self): 43 "Print ':', and increase the indentation." 44 self.write(":") 45 self._indent += 1 46 47 def leave(self): 48 "Decrease the indentation level." 49 self._indent -= 1 50 51 def dispatch(self, tree): 52 "Dispatcher function, dispatching tree type T to method _T." 53 if isinstance(tree, list): 54 for t in tree: 55 self.dispatch(t) 56 return 57 meth = getattr(self, "_"+tree.__class__.__name__) 58 meth(tree) 59 60 61 ############### Unparsing methods ###################### 62 # There should be one method per concrete grammar type # 63 # Constructors should be grouped by sum type. Ideally, # 64 # this would follow the order in the grammar, but # 65 # currently doesn't. # 66 ######################################################## 67 68 def _Module(self, tree): 69 for stmt in tree.body: 70 self.dispatch(stmt) 71 72 # stmt 73 def _Expr(self, tree): 74 self.fill() 75 self.dispatch(tree.value) 76 77 def _Import(self, t): 78 self.fill("import ") 79 interleave(lambda: self.write(", "), self.dispatch, t.names) 80 81 def _ImportFrom(self, t): 82 self.fill("from ") 83 self.write(t.module) 84 self.write(" import ") 85 interleave(lambda: self.write(", "), self.dispatch, t.names) 86 # XXX(jpe) what is level for? 87 88 def _Assign(self, t): 89 self.fill() 90 for target in t.targets: 91 self.dispatch(target) 92 self.write(" = ") 93 self.dispatch(t.value) 94 95 def _AugAssign(self, t): 96 self.fill() 97 self.dispatch(t.target) 98 self.write(" "+self.binop[t.op.__class__.__name__]+"= ") 99 self.dispatch(t.value) 100 101 def _Return(self, t): 102 self.fill("return") 103 if t.value: 104 self.write(" ") 105 self.dispatch(t.value) 106 107 def _Pass(self, t): 108 self.fill("pass") 109 110 def _Break(self, t): 111 self.fill("break") 112 113 def _Continue(self, t): 114 self.fill("continue") 115 116 def _Delete(self, t): 117 self.fill("del ") 118 self.dispatch(t.targets) 119 120 def _Assert(self, t): 121 self.fill("assert ") 122 self.dispatch(t.test) 123 if t.msg: 124 self.write(", ") 125 self.dispatch(t.msg) 126 127 def _Exec(self, t): 128 self.fill("exec ") 129 self.dispatch(t.body) 130 if t.globals: 131 self.write(" in ") 132 self.dispatch(t.globals) 133 if t.locals: 134 self.write(", ") 135 self.dispatch(t.locals) 136 137 def _Print(self, t): 138 self.fill("print ") 139 do_comma = False 140 if t.dest: 141 self.write(">>") 142 self.dispatch(t.dest) 143 do_comma = True 144 for e in t.values: 145 if do_comma:self.write(", ") 146 else:do_comma=True 147 self.dispatch(e) 148 if not t.nl: 149 self.write(",") 150 151 def _Global(self, t): 152 self.fill("global ") 153 interleave(lambda: self.write(", "), self.write, t.names) 154 155 def _Yield(self, t): 156 self.write("(") 157 self.write("yield") 158 if t.value: 159 self.write(" ") 160 self.dispatch(t.value) 161 self.write(")") 162 163 def _Raise(self, t): 164 self.fill('raise ') 165 if t.type: 166 self.dispatch(t.type) 167 if t.inst: 168 self.write(", ") 169 self.dispatch(t.inst) 170 if t.tback: 171 self.write(", ") 172 self.dispatch(t.tback) 173 174 def _TryExcept(self, t): 175 self.fill("try") 176 self.enter() 177 self.dispatch(t.body) 178 self.leave() 179 180 for ex in t.handlers: 181 self.dispatch(ex) 182 if t.orelse: 183 self.fill("else") 184 self.enter() 185 self.dispatch(t.orelse) 186 self.leave() 187 188 def _TryFinally(self, t): 189 self.fill("try") 190 self.enter() 191 self.dispatch(t.body) 192 self.leave() 193 194 self.fill("finally") 195 self.enter() 196 self.dispatch(t.finalbody) 197 self.leave() 198 199 def _ExceptHandler(self, t): 200 self.fill("except") 201 if t.type: 202 self.write(" ") 203 self.dispatch(t.type) 204 if t.name: 205 self.write(", ") 206 self.dispatch(t.name) 207 self.enter() 208 self.dispatch(t.body) 209 self.leave() 210 211 def _ClassDef(self, t): 212 self.write("\n") 213 self.fill("class "+t.name) 214 if t.bases: 215 self.write("(") 216 for a in t.bases: 217 self.dispatch(a) 218 self.write(", ") 219 self.write(")") 220 self.enter() 221 self.dispatch(t.body) 222 self.leave() 223 224 def _FunctionDef(self, t): 225 self.write("\n") 226 for deco in t.decorator_list: 227 self.fill("@") 228 self.dispatch(deco) 229 self.fill("def "+t.name + "(") 230 self.dispatch(t.args) 231 self.write(")") 232 self.enter() 233 self.dispatch(t.body) 234 self.leave() 235 236 def _For(self, t): 237 self.fill("for ") 238 self.dispatch(t.target) 239 self.write(" in ") 240 self.dispatch(t.iter) 241 self.enter() 242 self.dispatch(t.body) 243 self.leave() 244 if t.orelse: 245 self.fill("else") 246 self.enter() 247 self.dispatch(t.orelse) 248 self.leave 249 250 def _If(self, t): 251 self.fill("if ") 252 self.dispatch(t.test) 253 self.enter() 254 # XXX elif? 255 self.dispatch(t.body) 256 self.leave() 257 if t.orelse: 258 self.fill("else") 259 self.enter() 260 self.dispatch(t.orelse) 261 self.leave() 262 263 def _While(self, t): 264 self.fill("while ") 265 self.dispatch(t.test) 266 self.enter() 267 self.dispatch(t.body) 268 self.leave() 269 if t.orelse: 270 self.fill("else") 271 self.enter() 272 self.dispatch(t.orelse) 273 self.leave 274 275 def _With(self, t): 276 self.fill("with ") 277 self.dispatch(t.context_expr) 278 if t.optional_vars: 279 self.write(" as ") 280 self.dispatch(t.optional_vars) 281 self.enter() 282 self.dispatch(t.body) 283 self.leave() 284 285 # expr 286 def _Str(self, tree): 287 self.write(repr(tree.s)) 288 289 def _Name(self, t): 290 self.write(t.id) 291 292 def _Repr(self, t): 293 self.write("`") 294 self.dispatch(t.value) 295 self.write("`") 296 297 def _Num(self, t): 298 self.write(repr(t.n)) 299 300 def _List(self, t): 301 self.write("[") 302 interleave(lambda: self.write(", "), self.dispatch, t.elts) 303 self.write("]") 304 305 def _ListComp(self, t): 306 self.write("[") 307 self.dispatch(t.elt) 308 for gen in t.generators: 309 self.dispatch(gen) 310 self.write("]") 311 312 def _GeneratorExp(self, t): 313 self.write("(") 314 self.dispatch(t.elt) 315 for gen in t.generators: 316 self.dispatch(gen) 317 self.write(")") 318 319 def _comprehension(self, t): 320 self.write(" for ") 321 self.dispatch(t.target) 322 self.write(" in ") 323 self.dispatch(t.iter) 324 for if_clause in t.ifs: 325 self.write(" if ") 326 self.dispatch(if_clause) 327 328 def _IfExp(self, t): 329 self.write("(") 330 self.dispatch(t.body) 331 self.write(" if ") 332 self.dispatch(t.test) 333 self.write(" else ") 334 self.dispatch(t.orelse) 335 self.write(")") 336 337 def _Dict(self, t): 338 self.write("{") 339 def writem((k, v)): 340 self.dispatch(k) 341 self.write(": ") 342 self.dispatch(v) 343 interleave(lambda: self.write(", "), writem, zip(t.keys, t.values)) 344 self.write("}") 345 346 def _Tuple(self, t): 347 self.write("(") 348 if len(t.elts) == 1: 349 (elt,) = t.elts 350 self.dispatch(elt) 351 self.write(",") 352 else: 353 interleave(lambda: self.write(", "), self.dispatch, t.elts) 354 self.write(")") 355 356 unop = {"Invert":"~", "Not": "not", "UAdd":"+", "USub":"-"} 357 def _UnaryOp(self, t): 358 self.write(self.unop[t.op.__class__.__name__]) 359 self.write("(") 360 self.dispatch(t.operand) 361 self.write(")") 362 363 binop = { "Add":"+", "Sub":"-", "Mult":"*", "Div":"/", "Mod":"%", 364 "LShift":">>", "RShift":"<<", "BitOr":"|", "BitXor":"^", "BitAnd":"&", 365 "FloorDiv":"//", "Pow": "**"} 366 def _BinOp(self, t): 367 self.write("(") 368 self.dispatch(t.left) 369 self.write(" " + self.binop[t.op.__class__.__name__] + " ") 370 self.dispatch(t.right) 371 self.write(")") 372 373 cmpops = {"Eq":"==", "NotEq":"!=", "Lt":"<", "LtE":"<=", "Gt":">", "GtE":">=", 374 "Is":"is", "IsNot":"is not", "In":"in", "NotIn":"not in"} 375 def _Compare(self, t): 376 self.write("(") 377 self.dispatch(t.left) 378 for o, e in zip(t.ops, t.comparators): 379 self.write(" " + self.cmpops[o.__class__.__name__] + " ") 380 self.dispatch(e) 381 self.write(")") 382 383 boolops = {_ast.And: 'and', _ast.Or: 'or'} 384 def _BoolOp(self, t): 385 self.write("(") 386 s = " %s " % self.boolops[t.op.__class__] 387 interleave(lambda: self.write(s), self.dispatch, t.values) 388 self.write(")") 389 390 def _Attribute(self,t): 391 self.dispatch(t.value) 392 self.write(".") 393 self.write(t.attr) 394 395 def _Call(self, t): 396 self.dispatch(t.func) 397 self.write("(") 398 comma = False 399 for e in t.args: 400 if comma: self.write(", ") 401 else: comma = True 402 self.dispatch(e) 403 for e in t.keywords: 404 if comma: self.write(", ") 405 else: comma = True 406 self.dispatch(e) 407 if t.starargs: 408 if comma: self.write(", ") 409 else: comma = True 410 self.write("*") 411 self.dispatch(t.starargs) 412 if t.kwargs: 413 if comma: self.write(", ") 414 else: comma = True 415 self.write("**") 416 self.dispatch(t.kwargs) 417 self.write(")") 418 419 def _Subscript(self, t): 420 self.dispatch(t.value) 421 self.write("[") 422 self.dispatch(t.slice) 423 self.write("]") 424 425 # slice 426 def _Ellipsis(self, t): 427 self.write("...") 428 429 def _Index(self, t): 430 self.dispatch(t.value) 431 432 def _Slice(self, t): 433 if t.lower: 434 self.dispatch(t.lower) 435 self.write(":") 436 if t.upper: 437 self.dispatch(t.upper) 438 if t.step: 439 self.write(":") 440 self.dispatch(t.step) 441 442 def _ExtSlice(self, t): 443 interleave(lambda: self.write(', '), self.dispatch, t.dims) 444 445 # others 446 def _arguments(self, t): 447 first = True 448 nonDef = len(t.args)-len(t.defaults) 449 for a in t.args[0:nonDef]: 450 if first:first = False 451 else: self.write(", ") 452 self.dispatch(a) 453 for a,d in zip(t.args[nonDef:], t.defaults): 454 if first:first = False 455 else: self.write(", ") 456 self.dispatch(a), 457 self.write("=") 458 self.dispatch(d) 459 if t.vararg: 460 if first:first = False 461 else: self.write(", ") 462 self.write("*"+t.vararg) 463 if t.kwarg: 464 if first:first = False 465 else: self.write(", ") 466 self.write("**"+t.kwarg) 467 468 def _keyword(self, t): 469 self.write(t.arg) 470 self.write("=") 471 self.dispatch(t.value) 472 473 def _Lambda(self, t): 474 self.write("lambda ") 475 self.dispatch(t.args) 476 self.write(": ") 477 self.dispatch(t.body) 478 479 def _alias(self, t): 480 self.write(t.name) 481 if t.asname: 482 self.write(" as "+t.asname) 483 484def roundtrip(filename, output=sys.stdout): 485 source = open(filename).read() 486 tree = compile(source, filename, "exec", _ast.PyCF_ONLY_AST) 487 Unparser(tree, output) 488 489 490 491def testdir(a): 492 try: 493 names = [n for n in os.listdir(a) if n.endswith('.py')] 494 except OSError: 495 print >> sys.stderr, "Directory not readable: %s" % a 496 else: 497 for n in names: 498 fullname = os.path.join(a, n) 499 if os.path.isfile(fullname): 500 output = cStringIO.StringIO() 501 print 'Testing %s' % fullname 502 try: 503 roundtrip(fullname, output) 504 except Exception, e: 505 print ' Failed to compile, exception is %s' % repr(e) 506 elif os.path.isdir(fullname): 507 testdir(fullname) 508 509def main(args): 510 if args[0] == '--testdir': 511 for a in args[1:]: 512 testdir(a) 513 else: 514 for a in args: 515 roundtrip(a) 516 517if __name__=='__main__': 518 main(sys.argv[1:])