Parser/asdl_c.py

   1 #! /usr/bin/env python
   2 """Generate C code from an ASDL description."""
   3
   4 # TO DO
   5 # handle fields that have a type but no name
   6
   7 import os, sys, traceback
   8
   9 import asdl
  10
  11 TABSIZE = 8
  12 MAX_COL = 80
  13
  14 def get_c_type(name):
  15     """Return a string for the C name of the type.
  16
  17     This function special cases the default types provided by asdl:
  18     identifier, string, int, bool.
  19     """
  20     # XXX ack!  need to figure out where Id is useful and where string
  21     if isinstance(name, asdl.Id):
  22         name = name.value
  23     if name in asdl.builtin_types:
  24         return name
  25     else:
  26         return "%s_ty" % name
  27
  28 def reflow_lines(s, depth):
  29     """Reflow the line s indented depth tabs.
  30
  31     Return a sequence of lines where no line extends beyond MAX_COL
  32     when properly indented.  The first line is properly indented based
  33     exclusively on depth * TABSIZE.  All following lines -- these are
  34     the reflowed lines generated by this function -- start at the same
  35     column as the first character beyond the opening { in the first
  36     line.
  37     """
  38     size = MAX_COL - depth * TABSIZE
  39     if len(s) < size:
  40         return [s]
  41
  42     lines = []
  43     cur = s
  44     padding = ""
  45     while len(cur) > size:
  46         i = cur.rfind(' ', 0, size)
  47         # XXX this should be fixed for real
  48         if i == -1 and 'GeneratorExp' in cur:
  49             i = size + 3
  50         assert i != -1, "Impossible line %d to reflow: %r" % (size, s)
  51         lines.append(padding + cur[:i])
  52         if len(lines) == 1:
  53             # find new size based on brace
  54             j = cur.find('{', 0, i)
  55             if j >= 0:
  56                 j += 2 # account for the brace and the space after it
  57                 size -= j
  58                 padding = " " * j
  59             else:
  60                 j = cur.find('(', 0, i)
  61                 if j >= 0:
  62                     j += 1 # account for the paren (no space after it)
  63                     size -= j
  64                     padding = " " * j
  65         cur = cur[i+1:]
  66     else:
  67         lines.append(padding + cur)
  68     return lines
  69
  70 def is_simple(sum):
  71     """Return True if a sum is a simple.
  72
  73     A sum is simple if its types have no fields, e.g.
  74     unaryop = Invert | Not | UAdd | USub
  75     """
  76
  77     for t in sum.types:
  78         if t.fields:
  79             return False
  80     return True
  81
  82 class EmitVisitor(asdl.VisitorBase):
  83     """Visit that emits lines"""
  84
  85     def __init__(self, file):
  86         self.file = file
  87         super(EmitVisitor, self).__init__()
  88
  89     def emit(self, s, depth, reflow=1):
  90         # XXX reflow long lines?
  91         if reflow:
  92             lines = reflow_lines(s, depth)
  93         else:
  94             lines = [s]
  95         for line in lines:
  96             line = (" " * TABSIZE * depth) + line + "\n"
  97             self.file.write(line)
  98
  99 class TypeDefVisitor(EmitVisitor):
 100     def visitModule(self, mod):
 101         for dfn in mod.dfns:
 102             self.visit(dfn)
 103
 104     def visitType(self, type, depth=0):
 105         self.visit(type.value, type.name, depth)
 106
 107     def visitSum(self, sum, name, depth):
 108         if is_simple(sum):
 109             self.simple_sum(sum, name, depth)
 110         else:
 111             self.sum_with_constructors(sum, name, depth)
 112
 113     def simple_sum(self, sum, name, depth):
 114         enum = []
 115         for i in range(len(sum.types)):
 116             type = sum.types[i]
 117             enum.append("%s=%d" % (type.name, i + 1))
 118         enums = ", ".join(enum)
 119         ctype = get_c_type(name)
 120         s = "typedef enum _%s { %s } %s;" % (name, enums, ctype)
 121         self.emit(s, depth)
 122         self.emit("", depth)
 123
 124     def sum_with_constructors(self, sum, name, depth):
 125         ctype = get_c_type(name)
 126         s = "typedef struct _%(name)s *%(ctype)s;" % locals()
 127         self.emit(s, depth)
 128         self.emit("", depth)
 129
 130     def visitProduct(self, product, name, depth):
 131         ctype = get_c_type(name)
 132         s = "typedef struct _%(name)s *%(ctype)s;" % locals()
 133         self.emit(s, depth)
 134         self.emit("", depth)
 135
 136 class StructVisitor(EmitVisitor):
 137     """Visitor to generate typdefs for AST."""
 138
 139     def visitModule(self, mod):
 140         for dfn in mod.dfns:
 141             self.visit(dfn)
 142
 143     def visitType(self, type, depth=0):
 144         self.visit(type.value, type.name, depth)
 145
 146     def visitSum(self, sum, name, depth):
 147         if not is_simple(sum):
 148             self.sum_with_constructors(sum, name, depth)
 149
 150     def sum_with_constructors(self, sum, name, depth):
 151         def emit(s, depth=depth):
 152             self.emit(s % sys._getframe(1).f_locals, depth)
 153         enum = []
 154         for i in range(len(sum.types)):
 155             type = sum.types[i]
 156             enum.append("%s_kind=%d" % (type.name, i + 1))
 157
 158         emit("enum _%(name)s_kind {" + ", ".join(enum) + "};")
 159
 160         emit("struct _%(name)s {")
 161         emit("enum _%(name)s_kind kind;", depth + 1)
 162         emit("union {", depth + 1)
 163         for t in sum.types:
 164             self.visit(t, depth + 2)
 165         emit("} v;", depth + 1)
 166         for field in sum.attributes:
 167             # rudimentary attribute handling
 168             type = str(field.type)
 169             assert type in asdl.builtin_types, type
 170             emit("%s %s;" % (type, field.name), depth + 1);
 171         emit("};")
 172         emit("")
 173
 174     def visitConstructor(self, cons, depth):
 175         if cons.fields:
 176             self.emit("struct {", depth)
 177             for f in cons.fields:
 178                 self.visit(f, depth + 1)
 179             self.emit("} %s;" % cons.name, depth)
 180             self.emit("", depth)
 181         else:
 182             # XXX not sure what I want here, nothing is probably fine
 183             pass
 184
 185     def visitField(self, field, depth):
 186         # XXX need to lookup field.type, because it might be something
 187         # like a builtin...
 188         ctype = get_c_type(field.type)
 189         name = field.name
 190         if field.seq:
 191             if field.type.value in ('cmpop',):
 192                 self.emit("asdl_int_seq *%(name)s;" % locals(), depth)
 193             else:
 194                 self.emit("asdl_seq *%(name)s;" % locals(), depth)
 195         else:
 196             self.emit("%(ctype)s %(name)s;" % locals(), depth)
 197
 198     def visitProduct(self, product, name, depth):
 199         self.emit("struct _%(name)s {" % locals(), depth)
 200         for f in product.fields:
 201             self.visit(f, depth + 1)
 202         self.emit("};", depth)
 203         self.emit("", depth)
 204
 205 class PrototypeVisitor(EmitVisitor):
 206     """Generate function prototypes for the .h file"""
 207
 208     def visitModule(self, mod):
 209         for dfn in mod.dfns:
 210             self.visit(dfn)
 211
 212     def visitType(self, type):
 213         self.visit(type.value, type.name)
 214
 215     def visitSum(self, sum, name):
 216         if is_simple(sum):
 217             pass # XXX
 218         else:
 219             for t in sum.types:
 220                 self.visit(t, name, sum.attributes)
 221
 222     def get_args(self, fields):
 223         """Return list of C argument into, one for each field.
 224
 225         Argument info is 3-tuple of a C type, variable name, and flag
 226         that is true if type can be NULL.
 227         """
 228         args = []
 229         unnamed = {}
 230         for f in fields:
 231             if f.name is None:
 232                 name = f.type
 233                 c = unnamed[name] = unnamed.get(name, 0) + 1
 234                 if c > 1:
 235                     name = "name%d" % (c - 1)
 236             else:
 237                 name = f.name
 238             # XXX should extend get_c_type() to handle this
 239             if f.seq:
 240                 if f.type.value in ('cmpop',):
 241                     ctype = "asdl_int_seq *"
 242                 else:
 243                     ctype = "asdl_seq *"
 244             else:
 245                 ctype = get_c_type(f.type)
 246             args.append((ctype, name, f.opt or f.seq))
 247         return args
 248
 249     def visitConstructor(self, cons, type, attrs):
 250         args = self.get_args(cons.fields)
 251         attrs = self.get_args(attrs)
 252         ctype = get_c_type(type)
 253         self.emit_function(cons.name, ctype, args, attrs)
 254
 255     def emit_function(self, name, ctype, args, attrs, union=1):
 256         args = args + attrs
 257         if args:
 258             argstr = ", ".join(["%s %s" % (atype, aname)
 259                                 for atype, aname, opt in args])
 260             argstr += ", PyArena *arena"
 261         else:
 262             argstr = "PyArena *arena"
 263         margs = "a0"
 264         for i in range(1, len(args)+1):
 265             margs += ", a%d" % i
 266         self.emit("#define %s(%s) _Py_%s(%s)" % (name, margs, name, margs), 0,
 267                 reflow = 0)
 268         self.emit("%s _Py_%s(%s);" % (ctype, name, argstr), 0)
 269
 270     def visitProduct(self, prod, name):
 271         self.emit_function(name, get_c_type(name),
 272                            self.get_args(prod.fields), [], union=0)
 273
 274 class FunctionVisitor(PrototypeVisitor):
 275     """Visitor to generate constructor functions for AST."""
 276
 277     def emit_function(self, name, ctype, args, attrs, union=1):
 278         def emit(s, depth=0, reflow=1):
 279             self.emit(s, depth, reflow)
 280         argstr = ", ".join(["%s %s" % (atype, aname)
 281                             for atype, aname, opt in args + attrs])
 282         if argstr:
 283             argstr += ", PyArena *arena"
 284         else:
 285             argstr = "PyArena *arena"
 286         self.emit("%s" % ctype, 0)
 287         emit("%s(%s)" % (name, argstr))
 288         emit("{")
 289         emit("%s p;" % ctype, 1)
 290         for argtype, argname, opt in args:
 291             # XXX hack alert: false is allowed for a bool
 292             if not opt and not (argtype == "bool" or argtype == "int"):
 293                 emit("if (!%s) {" % argname, 1)
 294                 emit("PyErr_SetString(PyExc_ValueError,", 2)
 295                 msg = "field %s is required for %s" % (argname, name)
 296                 emit('                "%s");' % msg,
 297                      2, reflow=0)
 298                 emit('return NULL;', 2)
 299                 emit('}', 1)
 300
 301         emit("p = (%s)PyArena_Malloc(arena, sizeof(*p));" % ctype, 1);
 302         emit("if (!p)", 1)
 303         emit("return NULL;", 2)
 304         if union:
 305             self.emit_body_union(name, args, attrs)
 306         else:
 307             self.emit_body_struct(name, args, attrs)
 308         emit("return p;", 1)
 309         emit("}")
 310         emit("")
 311
 312     def emit_body_union(self, name, args, attrs):
 313         def emit(s, depth=0, reflow=1):
 314             self.emit(s, depth, reflow)
 315         emit("p->kind = %s_kind;" % name, 1)
 316         for argtype, argname, opt in args:
 317             emit("p->v.%s.%s = %s;" % (name, argname, argname), 1)
 318         for argtype, argname, opt in attrs:
 319             emit("p->%s = %s;" % (argname, argname), 1)
 320
 321     def emit_body_struct(self, name, args, attrs):
 322         def emit(s, depth=0, reflow=1):
 323             self.emit(s, depth, reflow)
 324         for argtype, argname, opt in args:
 325             emit("p->%s = %s;" % (argname, argname), 1)
 326         assert not attrs
 327
 328 class PickleVisitor(EmitVisitor):
 329
 330     def visitModule(self, mod):
 331         for dfn in mod.dfns:
 332             self.visit(dfn)
 333
 334     def visitType(self, type):
 335         self.visit(type.value, type.name)
 336
 337     def visitSum(self, sum, name):
 338         pass
 339
 340     def visitProduct(self, sum, name):
 341         pass
 342
 343     def visitConstructor(self, cons, name):
 344         pass
 345
 346     def visitField(self, sum):
 347         pass
 348
 349 class MarshalPrototypeVisitor(PickleVisitor):
 350
 351     def prototype(self, sum, name):
 352         ctype = get_c_type(name)
 353         self.emit("static int marshal_write_%s(PyObject **, int *, %s);"
 354                   % (name, ctype), 0)
 355
 356     visitProduct = visitSum = prototype
 357
 358 class PyTypesDeclareVisitor(PickleVisitor):
 359
 360     def visitProduct(self, prod, name):
 361         self.emit("static PyTypeObject *%s_type;" % name, 0)
 362         self.emit("static PyObject* ast2obj_%s(void*);" % name, 0)
 363         if prod.fields:
 364             self.emit("static char *%s_fields[]={" % name,0)
 365             for f in prod.fields:
 366                 self.emit('"%s",' % f.name, 1)
 367             self.emit("};", 0)
 368
 369     def visitSum(self, sum, name):
 370         self.emit("static PyTypeObject *%s_type;" % name, 0)
 371         if sum.attributes:
 372             self.emit("static char *%s_attributes[] = {" % name, 0)
 373             for a in sum.attributes:
 374                 self.emit('"%s",' % a.name, 1)
 375             self.emit("};", 0)
 376         ptype = "void*"
 377         if is_simple(sum):
 378             ptype = get_c_type(name)
 379             tnames = []
 380             for t in sum.types:
 381                 tnames.append(str(t.name)+"_singleton")
 382             tnames = ", *".join(tnames)
 383             self.emit("static PyObject *%s;" % tnames, 0)
 384         self.emit("static PyObject* ast2obj_%s(%s);" % (name, ptype), 0)
 385         for t in sum.types:
 386             self.visitConstructor(t, name)
 387
 388     def visitConstructor(self, cons, name):
 389         self.emit("static PyTypeObject *%s_type;" % cons.name, 0)
 390         if cons.fields:
 391             self.emit("static char *%s_fields[]={" % cons.name, 0)
 392             for t in cons.fields:
 393                 self.emit('"%s",' % t.name, 1)
 394             self.emit("};",0)
 395
 396 class PyTypesVisitor(PickleVisitor):
 397
 398     def visitModule(self, mod):
 399         self.emit("""
 400 static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int num_fields)
 401 {
 402     PyObject *fnames, *result;
 403     int i;
 404     if (num_fields) {
 405         fnames = PyTuple_New(num_fields);
 406         if (!fnames) return NULL;
 407     } else {
 408         fnames = Py_None;
 409         Py_INCREF(Py_None);
 410     }
 411     for(i=0; i < num_fields; i++) {
 412         PyObject *field = PyString_FromString(fields[i]);
 413         if (!field) {
 414             Py_DECREF(fnames);
 415             return NULL;
 416         }
 417         PyTuple_SET_ITEM(fnames, i, field);
 418     }
 419     result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){sOss}",
 420                     type, base, "_fields", fnames, "__module__", "_ast");
 421     Py_DECREF(fnames);
 422     return (PyTypeObject*)result;
 423 }
 424
 425 static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
 426 {
 427     int i, result;
 428     PyObject *s, *l = PyList_New(num_fields);
 429     if (!l) return 0;
 430     for(i = 0; i < num_fields; i++) {
 431         s = PyString_FromString(attrs[i]);
 432         if (!s) {
 433             Py_DECREF(l);
 434             return 0;
 435         }
 436         PyList_SET_ITEM(l, i, s);
 437     }
 438     result = PyObject_SetAttrString((PyObject*)type, "_attributes", l) >= 0;
 439     Py_DECREF(l);
 440     return result;
 441 }
 442
 443 static PyObject* ast2obj_list(asdl_seq *seq, PyObject* (*func)(void*))
 444 {
 445     int i, n = asdl_seq_LEN(seq);
 446     PyObject *result = PyList_New(n);
 447     PyObject *value;
 448     if (!result)
 449         return NULL;
 450     for (i = 0; i < n; i++) {
 451         value = func(asdl_seq_GET(seq, i));
 452         if (!value) {
 453             Py_DECREF(result);
 454             return NULL;
 455         }
 456         PyList_SET_ITEM(result, i, value);
 457     }
 458     return result;
 459 }
 460
 461 static PyObject* ast2obj_object(void *o)
 462 {
 463     if (!o)
 464         o = Py_None;
 465     Py_INCREF((PyObject*)o);
 466     return (PyObject*)o;
 467 }
 468 #define ast2obj_identifier ast2obj_object
 469 #define ast2obj_string ast2obj_object
 470 static PyObject* ast2obj_bool(bool b)
 471 {
 472     return PyBool_FromLong(b);
 473 }
 474
 475 static PyObject* ast2obj_int(long b)
 476 {
 477     return PyInt_FromLong(b);
 478 }
 479 """, 0, reflow=False)
 480
 481         self.emit("static int init_types(void)",0)
 482         self.emit("{", 0)
 483         self.emit("static int initialized;", 1)
 484         self.emit("if (initialized) return 1;", 1)
 485         self.emit('AST_type = make_type("AST", &PyBaseObject_Type, NULL, 0);', 1)
 486         for dfn in mod.dfns:
 487             self.visit(dfn)
 488         self.emit("initialized = 1;", 1)
 489         self.emit("return 1;", 1);
 490         self.emit("}", 0)
 491
 492     def visitProduct(self, prod, name):
 493         if prod.fields:
 494             fields = name.value+"_fields"
 495         else:
 496             fields = "NULL"
 497         self.emit('%s_type = make_type("%s", AST_type, %s, %d);' %
 498                         (name, name, fields, len(prod.fields)), 1)
 499         self.emit("if (!%s_type) return 0;" % name, 1)
 500
 501     def visitSum(self, sum, name):
 502         self.emit('%s_type = make_type("%s", AST_type, NULL, 0);' % (name, name), 1)
 503         self.emit("if (!%s_type) return 0;" % name, 1)
 504         if sum.attributes:
 505             self.emit("if (!add_attributes(%s_type, %s_attributes, %d)) return 0;" %
 506                             (name, name, len(sum.attributes)), 1)
 507         else:
 508             self.emit("if (!add_attributes(%s_type, NULL, 0)) return 0;" % name, 1)
 509         simple = is_simple(sum)
 510         for t in sum.types:
 511             self.visitConstructor(t, name, simple)
 512
 513     def visitConstructor(self, cons, name, simple):
 514         if cons.fields:
 515             fields = cons.name.value+"_fields"
 516         else:
 517             fields = "NULL"
 518         self.emit('%s_type = make_type("%s", %s_type, %s, %d);' %
 519                             (cons.name, cons.name, name, fields, len(cons.fields)), 1)
 520         self.emit("if (!%s_type) return 0;" % cons.name, 1)
 521         if simple:
 522             self.emit("%s_singleton = PyType_GenericNew(%s_type, NULL, NULL);" %
 523                              (cons.name, cons.name), 1)
 524             self.emit("if (!%s_singleton) return 0;" % cons.name, 1)
 525
 526 def parse_version(mod):
 527     return mod.version.value[12:-3]
 528
 529 class ASTModuleVisitor(PickleVisitor):
 530
 531     def visitModule(self, mod):
 532         self.emit("PyMODINIT_FUNC", 0)
 533         self.emit("init_ast(void)", 0)
 534         self.emit("{", 0)
 535         self.emit("PyObject *m, *d;", 1)
 536         self.emit("if (!init_types()) return;", 1)
 537         self.emit('m = Py_InitModule3("_ast", NULL, NULL);', 1)
 538         self.emit("if (!m) return;", 1)
 539         self.emit("d = PyModule_GetDict(m);", 1)
 540         self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;', 1)
 541         self.emit('if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)', 1)
 542         self.emit("return;", 2)
 543         # Value of version: "$Revision$"
 544         self.emit('if (PyModule_AddStringConstant(m, "__version__", "%s") < 0)'
 545                 % parse_version(mod), 1)
 546         self.emit("return;", 2)
 547         for dfn in mod.dfns:
 548             self.visit(dfn)
 549         self.emit("}", 0)
 550
 551     def visitProduct(self, prod, name):
 552         self.addObj(name)
 553
 554     def visitSum(self, sum, name):
 555         self.addObj(name)
 556         for t in sum.types:
 557             self.visitConstructor(t, name)
 558
 559     def visitConstructor(self, cons, name):
 560         self.addObj(cons.name)
 561
 562     def addObj(self, name):
 563         self.emit('if (PyDict_SetItemString(d, "%s", (PyObject*)%s_type) < 0) return;' % (name, name), 1)
 564
 565 _SPECIALIZED_SEQUENCES = ('stmt', 'expr')
 566
 567 def find_sequence(fields, doing_specialization):
 568     """Return True if any field uses a sequence."""
 569     for f in fields:
 570         if f.seq:
 571             if not doing_specialization:
 572                 return True
 573             if str(f.type) not in _SPECIALIZED_SEQUENCES:
 574                 return True
 575     return False
 576
 577 def has_sequence(types, doing_specialization):
 578     for t in types:
 579         if find_sequence(t.fields, doing_specialization):
 580             return True
 581     return False
 582
 583
 584 class StaticVisitor(PickleVisitor):
 585     CODE = '''Very simple, always emit this static code.  Overide CODE'''
 586
 587     def visit(self, object):
 588         self.emit(self.CODE, 0, reflow=False)
 589
 590 class ObjVisitor(PickleVisitor):
 591
 592     def func_begin(self, name):
 593         ctype = get_c_type(name)
 594         self.emit("PyObject*", 0)
 595         self.emit("ast2obj_%s(void* _o)" % (name), 0)
 596         self.emit("{", 0)
 597         self.emit("%s o = (%s)_o;" % (ctype, ctype), 1)
 598         self.emit("PyObject *result = NULL, *value = NULL;", 1)
 599         self.emit('if (!o) {', 1)
 600         self.emit("Py_INCREF(Py_None);", 2)
 601         self.emit('return Py_None;', 2)
 602         self.emit("}", 1)
 603         self.emit('', 0)
 604
 605     def func_end(self):
 606         self.emit("return result;", 1)
 607         self.emit("failed:", 0)
 608         self.emit("Py_XDECREF(value);", 1)
 609         self.emit("Py_XDECREF(result);", 1)
 610         self.emit("return NULL;", 1)
 611         self.emit("}", 0)
 612         self.emit("", 0)
 613
 614     def visitSum(self, sum, name):
 615         if is_simple(sum):
 616             self.simpleSum(sum, name)
 617             return
 618         self.func_begin(name)
 619         self.emit("switch (o->kind) {", 1)
 620         for i in range(len(sum.types)):
 621             t = sum.types[i]
 622             self.visitConstructor(t, i + 1, name)
 623         self.emit("}", 1)
 624         for a in sum.attributes:
 625             self.emit("value = ast2obj_%s(o->%s);" % (a.type, a.name), 1)
 626             self.emit("if (!value) goto failed;", 1)
 627             self.emit('if (PyObject_SetAttrString(result, "%s", value) < 0)' % a.name, 1)
 628             self.emit('goto failed;', 2)
 629             self.emit('Py_DECREF(value);', 1)
 630         self.func_end()
 631
 632     def simpleSum(self, sum, name):
 633         self.emit("PyObject* ast2obj_%s(%s_ty o)" % (name, name), 0)
 634         self.emit("{", 0)
 635         self.emit("switch(o) {", 1)
 636         for t in sum.types:
 637             self.emit("case %s:" % t.name, 2)
 638             self.emit("Py_INCREF(%s_singleton);" % t.name, 3)
 639             self.emit("return %s_singleton;" % t.name, 3)
 640         self.emit("}", 1)
 641         self.emit("return NULL; /* cannot happen */", 1)
 642         self.emit("}", 0)
 643
 644     def visitProduct(self, prod, name):
 645         self.func_begin(name)
 646         self.emit("result = PyType_GenericNew(%s_type, NULL, NULL);" % name, 1);
 647         self.emit("if (!result) return NULL;", 1)
 648         for field in prod.fields:
 649             self.visitField(field, name, 1, True)
 650         self.func_end()
 651
 652     def visitConstructor(self, cons, enum, name):
 653         self.emit("case %s_kind:" % cons.name, 1)
 654         self.emit("result = PyType_GenericNew(%s_type, NULL, NULL);" % cons.name, 2);
 655         self.emit("if (!result) goto failed;", 2)
 656         for f in cons.fields:
 657             self.visitField(f, cons.name, 2, False)
 658         self.emit("break;", 2)
 659
 660     def visitField(self, field, name, depth, product):
 661         def emit(s, d):
 662             self.emit(s, depth + d)
 663         if product:
 664             value = "o->%s" % field.name
 665         else:
 666             value = "o->v.%s.%s" % (name, field.name)
 667         self.set(field, value, depth)
 668         emit("if (!value) goto failed;", 0)
 669         emit('if (PyObject_SetAttrString(result, "%s", value) == -1)' % field.name, 0)
 670         emit("goto failed;", 1)
 671         emit("Py_DECREF(value);", 0)
 672
 673     def emitSeq(self, field, value, depth, emit):
 674         emit("seq = %s;" % value, 0)
 675         emit("n = asdl_seq_LEN(seq);", 0)
 676         emit("value = PyList_New(n);", 0)
 677         emit("if (!value) goto failed;", 0)
 678         emit("for (i = 0; i < n; i++) {", 0)
 679         self.set("value", field, "asdl_seq_GET(seq, i)", depth + 1)
 680         emit("if (!value1) goto failed;", 1)
 681         emit("PyList_SET_ITEM(value, i, value1);", 1)
 682         emit("value1 = NULL;", 1)
 683         emit("}", 0)
 684
 685     def set(self, field, value, depth):
 686         if field.seq:
 687             # XXX should really check for is_simple, but that requires a symbol table
 688             if field.type.value == "cmpop":
 689                 # While the sequence elements are stored as void*,
 690                 # ast2obj_cmpop expects an enum
 691                 self.emit("{", depth)
 692                 self.emit("int i, n = asdl_seq_LEN(%s);" % value, depth+1)
 693                 self.emit("value = PyList_New(n);", depth+1)
 694                 self.emit("if (!value) goto failed;", depth+1)
 695                 self.emit("for(i = 0; i < n; i++)", depth+1)
 696                 # This cannot fail, so no need for error handling
 697                 self.emit("PyList_SET_ITEM(value, i, ast2obj_cmpop((cmpop_ty)asdl_seq_GET(%s, i)));" % value,
 698                           depth+2, reflow=False)
 699                 self.emit("}", depth)
 700             else:
 701                 self.emit("value = ast2obj_list(%s, ast2obj_%s);" % (value, field.type), depth)
 702         else:
 703             ctype = get_c_type(field.type)
 704             self.emit("value = ast2obj_%s(%s);" % (field.type, value), depth, reflow=False)
 705
 706
 707 class PartingShots(StaticVisitor):
 708
 709     CODE = """
 710 PyObject* PyAST_mod2obj(mod_ty t)
 711 {
 712     init_types();
 713     return ast2obj_mod(t);
 714 }
 715 """
 716
 717 class ChainOfVisitors:
 718     def __init__(self, *visitors):
 719         self.visitors = visitors
 720
 721     def visit(self, object):
 722         for v in self.visitors:
 723             v.visit(object)
 724             v.emit("", 0)
 725
 726 common_msg = "/* File automatically generated by %s. */\n"
 727
 728 c_file_msg = """
 729 /*
 730    __version__ %s.
 731
 732    This module must be committed separately after each AST grammar change;
 733    The __version__ number is set to the revision number of the commit
 734    containing the grammar change.
 735 */
 736 """
 737
 738 def main(srcfile):
 739     argv0 = sys.argv[0]
 740     components = argv0.split(os.sep)
 741     argv0 = os.sep.join(components[-2:])
 742     auto_gen_msg = common_msg % argv0
 743     mod = asdl.parse(srcfile)
 744     if not asdl.check(mod):
 745         sys.exit(1)
 746     if INC_DIR:
 747         p = "%s/%s-ast.h" % (INC_DIR, mod.name)
 748         f = open(p, "wb")
 749         print >> f, auto_gen_msg
 750         print >> f, '#include "asdl.h"\n'
 751         c = ChainOfVisitors(TypeDefVisitor(f),
 752                             StructVisitor(f),
 753                             PrototypeVisitor(f),
 754                             )
 755         c.visit(mod)
 756         print >>f, "PyObject* PyAST_mod2obj(mod_ty t);"
 757         f.close()
 758
 759     if SRC_DIR:
 760         p = os.path.join(SRC_DIR, str(mod.name) + "-ast.c")
 761         f = open(p, "wb")
 762         print >> f, auto_gen_msg
 763         print >> f, c_file_msg % parse_version(mod)
 764         print >> f, '#include "Python.h"'
 765         print >> f, '#include "%s-ast.h"' % mod.name
 766         print >> f
 767         print >>f, "static PyTypeObject* AST_type;"
 768         v = ChainOfVisitors(
 769             PyTypesDeclareVisitor(f),
 770             PyTypesVisitor(f),
 771             FunctionVisitor(f),
 772             ObjVisitor(f),
 773             ASTModuleVisitor(f),
 774             PartingShots(f),
 775             )
 776         v.visit(mod)
 777         f.close()
 778
 779 if __name__ == "__main__":
 780     import sys
 781     import getopt
 782
 783     INC_DIR = ''
 784     SRC_DIR = ''
 785     opts, args = getopt.getopt(sys.argv[1:], "h:c:")
 786     if len(opts) != 1:
 787         print "Must specify exactly one output file"
 788         sys.exit(1)
 789     for o, v in opts:
 790         if o == '-h':
 791             INC_DIR = v
 792         if o == '-c':
 793             SRC_DIR = v
 794     if len(args) != 1:
 795         print "Must specify single input file"
 796         sys.exit(1)
 797     main(args[0])