aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/tools/cython/Cython/CodeWriter.py
blob: a5453b90bcf12c3ceae48989f1ddd98638deb165 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
"""
Serializes a Cython code tree to Cython code. This is primarily useful for
debugging and testing purposes.

The output is in a strict format, no whitespace or comments from the input
is preserved (and it could not be as it is not present in the code tree).
"""

from __future__ import absolute_import, print_function

from .Compiler.Visitor import TreeVisitor
from .Compiler.ExprNodes import *


class LinesResult(object):
    def __init__(self):
        self.lines = []
        self.s = u""

    def put(self, s):
        self.s += s

    def newline(self):
        self.lines.append(self.s)
        self.s = u""

    def putline(self, s):
        self.put(s)
        self.newline()

class DeclarationWriter(TreeVisitor):

    indent_string = u"    "

    def __init__(self, result=None):
        super(DeclarationWriter, self).__init__()
        if result is None:
            result = LinesResult()
        self.result = result
        self.numindents = 0
        self.tempnames = {}
        self.tempblockindex = 0

    def write(self, tree):
        self.visit(tree)
        return self.result

    def indent(self):
        self.numindents += 1

    def dedent(self):
        self.numindents -= 1

    def startline(self, s=u""):
        self.result.put(self.indent_string * self.numindents + s)

    def put(self, s):
        self.result.put(s)

    def putline(self, s):
        self.result.putline(self.indent_string * self.numindents + s)

    def endline(self, s=u""):
        self.result.putline(s)

    def line(self, s):
        self.startline(s)
        self.endline()

    def comma_separated_list(self, items, output_rhs=False):
        if len(items) > 0:
            for item in items[:-1]:
                self.visit(item)
                if output_rhs and item.default is not None:
                    self.put(u" = ")
                    self.visit(item.default)
                self.put(u", ")
            self.visit(items[-1])

    def visit_Node(self, node):
        raise AssertionError("Node not handled by serializer: %r" % node)

    def visit_ModuleNode(self, node):
        self.visitchildren(node)

    def visit_StatListNode(self, node):
        self.visitchildren(node)

    def visit_CDefExternNode(self, node):
        if node.include_file is None:
            file = u'*'
        else:
            file = u'"%s"' % node.include_file
        self.putline(u"cdef extern from %s:" % file)
        self.indent()
        self.visit(node.body)
        self.dedent()

    def visit_CPtrDeclaratorNode(self, node):
        self.put('*')
        self.visit(node.base)

    def visit_CReferenceDeclaratorNode(self, node):
        self.put('&')
        self.visit(node.base)

    def visit_CArrayDeclaratorNode(self, node):
        self.visit(node.base)
        self.put(u'[')
        if node.dimension is not None:
            self.visit(node.dimension)
        self.put(u']')

    def visit_CArrayDeclaratorNode(self, node):
        self.visit(node.base)
        self.put(u'[')
        if node.dimension is not None:
            self.visit(node.dimension)
        self.put(u']')

    def visit_CFuncDeclaratorNode(self, node):
        # TODO: except, gil, etc.
        self.visit(node.base)
        self.put(u'(')
        self.comma_separated_list(node.args)
        self.endline(u')')

    def visit_CNameDeclaratorNode(self, node):
        self.put(node.name)

    def visit_CSimpleBaseTypeNode(self, node):
        # See Parsing.p_sign_and_longness
        if node.is_basic_c_type:
            self.put(("unsigned ", "", "signed ")[node.signed])
            if node.longness < 0:
                self.put("short " * -node.longness)
            elif node.longness > 0:
                self.put("long " * node.longness)
        self.put(node.name)

    def visit_CComplexBaseTypeNode(self, node):
        self.put(u'(')
        self.visit(node.base_type)
        self.visit(node.declarator)
        self.put(u')')

    def visit_CNestedBaseTypeNode(self, node):
        self.visit(node.base_type)
        self.put(u'.')
        self.put(node.name)

    def visit_TemplatedTypeNode(self, node):
        self.visit(node.base_type_node)
        self.put(u'[')
        self.comma_separated_list(node.positional_args + node.keyword_args.key_value_pairs)
        self.put(u']')

    def visit_CVarDefNode(self, node):
        self.startline(u"cdef ")
        self.visit(node.base_type)
        self.put(u" ")
        self.comma_separated_list(node.declarators, output_rhs=True)
        self.endline()

    def visit_container_node(self, node, decl, extras, attributes):
        # TODO: visibility
        self.startline(decl)
        if node.name:
            self.put(u' ')
            self.put(node.name)
            if node.cname is not None:
                self.put(u' "%s"' % node.cname)
        if extras:
            self.put(extras)
        self.endline(':')
        self.indent()
        if not attributes:
            self.putline('pass')
        else:
            for attribute in attributes:
                self.visit(attribute)
        self.dedent()

    def visit_CStructOrUnionDefNode(self, node):
        if node.typedef_flag:
            decl = u'ctypedef '
        else:
            decl = u'cdef '
        if node.visibility == 'public':
            decl += u'public '
        if node.packed:
            decl += u'packed '
        decl += node.kind
        self.visit_container_node(node, decl, None, node.attributes)

    def visit_CppClassNode(self, node):
        extras = ""
        if node.templates:
            extras = u"[%s]" % ", ".join(node.templates)
        if node.base_classes:
            extras += "(%s)" % ", ".join(node.base_classes)
        self.visit_container_node(node, u"cdef cppclass", extras, node.attributes)

    def visit_CEnumDefNode(self, node):
        self.visit_container_node(node, u"cdef enum", None, node.items)

    def visit_CEnumDefItemNode(self, node):
        self.startline(node.name)
        if node.cname:
            self.put(u' "%s"' % node.cname)
        if node.value:
            self.put(u" = ")
            self.visit(node.value)
        self.endline()

    def visit_CClassDefNode(self, node):
        assert not node.module_name
        if node.decorators:
            for decorator in node.decorators:
                self.visit(decorator)
        self.startline(u"cdef class ")
        self.put(node.class_name)
        if node.base_class_name:
            self.put(u"(")
            if node.base_class_module:
                self.put(node.base_class_module)
                self.put(u".")
            self.put(node.base_class_name)
            self.put(u")")
        self.endline(u":")
        self.indent()
        self.visit(node.body)
        self.dedent()

    def visit_CTypeDefNode(self, node):
        self.startline(u"ctypedef ")
        self.visit(node.base_type)
        self.put(u" ")
        self.visit(node.declarator)
        self.endline()

    def visit_FuncDefNode(self, node):
        self.startline(u"def %s(" % node.name)
        self.comma_separated_list(node.args)
        self.endline(u"):")
        self.indent()
        self.visit(node.body)
        self.dedent()

    def visit_CArgDeclNode(self, node):
        if node.base_type.name is not None:
            self.visit(node.base_type)
            self.put(u" ")
        self.visit(node.declarator)
        if node.default is not None:
            self.put(u" = ")
            self.visit(node.default)

    def visit_CImportStatNode(self, node):
        self.startline(u"cimport ")
        self.put(node.module_name)
        if node.as_name:
            self.put(u" as ")
            self.put(node.as_name)
        self.endline()

    def visit_FromCImportStatNode(self, node):
        self.startline(u"from ")
        self.put(node.module_name)
        self.put(u" cimport ")
        first = True
        for pos, name, as_name, kind in node.imported_names:
            assert kind is None
            if first:
                first = False
            else:
                self.put(u", ")
            self.put(name)
            if as_name:
                self.put(u" as ")
                self.put(as_name)
        self.endline()

    def visit_NameNode(self, node):
        self.put(node.name)

    def visit_IntNode(self, node):
        self.put(node.value)

    def visit_NoneNode(self, node):
        self.put(u"None")

    def visit_NotNode(self, node):
        self.put(u"(not ")
        self.visit(node.operand)
        self.put(u")")

    def visit_DecoratorNode(self, node):
        self.startline("@")
        self.visit(node.decorator)
        self.endline()

    def visit_BinopNode(self, node):
        self.visit(node.operand1)
        self.put(u" %s " % node.operator)
        self.visit(node.operand2)

    def visit_AttributeNode(self, node):
        self.visit(node.obj)
        self.put(u".%s" % node.attribute)

    def visit_BoolNode(self, node):
        self.put(str(node.value))

    # FIXME: represent string nodes correctly
    def visit_StringNode(self, node):
        value = node.value
        if value.encoding is not None:
            value = value.encode(value.encoding)
        self.put(repr(value))

    def visit_PassStatNode(self, node):
        self.startline(u"pass")
        self.endline()

class CodeWriter(DeclarationWriter):

    def visit_SingleAssignmentNode(self, node):
        self.startline()
        self.visit(node.lhs)
        self.put(u" = ")
        self.visit(node.rhs)
        self.endline()

    def visit_CascadedAssignmentNode(self, node):
        self.startline()
        for lhs in node.lhs_list:
            self.visit(lhs)
            self.put(u" = ")
        self.visit(node.rhs)
        self.endline()

    def visit_PrintStatNode(self, node):
        self.startline(u"print ")
        self.comma_separated_list(node.arg_tuple.args)
        if not node.append_newline:
            self.put(u",")
        self.endline()

    def visit_ForInStatNode(self, node):
        self.startline(u"for ")
        self.visit(node.target)
        self.put(u" in ")
        self.visit(node.iterator.sequence)
        self.endline(u":")
        self.indent()
        self.visit(node.body)
        self.dedent()
        if node.else_clause is not None:
            self.line(u"else:")
            self.indent()
            self.visit(node.else_clause)
            self.dedent()

    def visit_IfStatNode(self, node):
        # The IfClauseNode is handled directly without a separate match
        # for clariy.
        self.startline(u"if ")
        self.visit(node.if_clauses[0].condition)
        self.endline(":")
        self.indent()
        self.visit(node.if_clauses[0].body)
        self.dedent()
        for clause in node.if_clauses[1:]:
            self.startline("elif ")
            self.visit(clause.condition)
            self.endline(":")
            self.indent()
            self.visit(clause.body)
            self.dedent()
        if node.else_clause is not None:
            self.line("else:")
            self.indent()
            self.visit(node.else_clause)
            self.dedent()

    def visit_SequenceNode(self, node):
        self.comma_separated_list(node.args) # Might need to discover whether we need () around tuples...hmm...

    def visit_SimpleCallNode(self, node):
        self.visit(node.function)
        self.put(u"(")
        self.comma_separated_list(node.args)
        self.put(")")

    def visit_GeneralCallNode(self, node):
        self.visit(node.function)
        self.put(u"(")
        posarg = node.positional_args
        if isinstance(posarg, AsTupleNode):
            self.visit(posarg.arg)
        else:
            self.comma_separated_list(posarg.args)  # TupleNode.args
        if node.keyword_args:
            if isinstance(node.keyword_args, DictNode):
                for i, (name, value) in enumerate(node.keyword_args.key_value_pairs):
                    if i > 0:
                        self.put(', ')
                    self.visit(name)
                    self.put('=')
                    self.visit(value)
            else:
                raise Exception("Not implemented yet")
        self.put(u")")

    def visit_ExprStatNode(self, node):
        self.startline()
        self.visit(node.expr)
        self.endline()

    def visit_InPlaceAssignmentNode(self, node):
        self.startline()
        self.visit(node.lhs)
        self.put(u" %s= " % node.operator)
        self.visit(node.rhs)
        self.endline()

    def visit_WithStatNode(self, node):
        self.startline()
        self.put(u"with ")
        self.visit(node.manager)
        if node.target is not None:
            self.put(u" as ")
            self.visit(node.target)
        self.endline(u":")
        self.indent()
        self.visit(node.body)
        self.dedent()

    def visit_TryFinallyStatNode(self, node):
        self.line(u"try:")
        self.indent()
        self.visit(node.body)
        self.dedent()
        self.line(u"finally:")
        self.indent()
        self.visit(node.finally_clause)
        self.dedent()

    def visit_TryExceptStatNode(self, node):
        self.line(u"try:")
        self.indent()
        self.visit(node.body)
        self.dedent()
        for x in node.except_clauses:
            self.visit(x)
        if node.else_clause is not None:
            self.visit(node.else_clause)

    def visit_ExceptClauseNode(self, node):
        self.startline(u"except")
        if node.pattern is not None:
            self.put(u" ")
            self.visit(node.pattern)
        if node.target is not None:
            self.put(u", ")
            self.visit(node.target)
        self.endline(":")
        self.indent()
        self.visit(node.body)
        self.dedent()

    def visit_ReturnStatNode(self, node):
        self.startline("return ")
        self.visit(node.value)
        self.endline()

    def visit_ReraiseStatNode(self, node):
        self.line("raise")

    def visit_ImportNode(self, node):
        self.put(u"(import %s)" % node.module_name.value)

    def visit_TempsBlockNode(self, node):
        """
        Temporaries are output like $1_1', where the first number is
        an index of the TempsBlockNode and the second number is an index
        of the temporary which that block allocates.
        """
        idx = 0
        for handle in node.temps:
            self.tempnames[handle] = "$%d_%d" % (self.tempblockindex, idx)
            idx += 1
        self.tempblockindex += 1
        self.visit(node.body)

    def visit_TempRefNode(self, node):
        self.put(self.tempnames[node.handle])


class PxdWriter(DeclarationWriter):
    def __call__(self, node):
        print(u'\n'.join(self.write(node).lines))
        return node

    def visit_CFuncDefNode(self, node):
        if 'inline' in node.modifiers:
            return
        if node.overridable:
            self.startline(u'cpdef ')
        else:
            self.startline(u'cdef ')
        if node.visibility != 'private':
            self.put(node.visibility)
            self.put(u' ')
        if node.api:
            self.put(u'api ')
        self.visit(node.declarator)

    def visit_StatNode(self, node):
        pass


class ExpressionWriter(TreeVisitor):

    def __init__(self, result=None):
        super(ExpressionWriter, self).__init__()
        if result is None:
            result = u""
        self.result = result
        self.precedence = [0]

    def write(self, tree):
        self.visit(tree)
        return self.result

    def put(self, s):
        self.result += s

    def remove(self, s):
        if self.result.endswith(s):
            self.result = self.result[:-len(s)]

    def comma_separated_list(self, items):
        if len(items) > 0:
            for item in items[:-1]:
                self.visit(item)
                self.put(u", ")
            self.visit(items[-1])

    def visit_Node(self, node):
        raise AssertionError("Node not handled by serializer: %r" % node)

    def visit_NameNode(self, node):
        self.put(node.name)

    def visit_NoneNode(self, node):
        self.put(u"None")

    def visit_EllipsisNode(self, node):
        self.put(u"...")

    def visit_BoolNode(self, node):
        self.put(str(node.value))

    def visit_ConstNode(self, node):
        self.put(str(node.value))

    def visit_ImagNode(self, node):
        self.put(node.value)
        self.put(u"j")

    def emit_string(self, node, prefix=u""):
        repr_val = repr(node.value)
        if repr_val[0] in 'ub':
            repr_val = repr_val[1:]
        self.put(u"%s%s" % (prefix, repr_val))

    def visit_BytesNode(self, node):
        self.emit_string(node, u"b")

    def visit_StringNode(self, node):
        self.emit_string(node)

    def visit_UnicodeNode(self, node):
        self.emit_string(node, u"u")

    def emit_sequence(self, node, parens=(u"", u"")):
        open_paren, close_paren = parens
        items = node.subexpr_nodes()
        self.put(open_paren)
        self.comma_separated_list(items)
        self.put(close_paren)

    def visit_ListNode(self, node):
        self.emit_sequence(node, u"[]")

    def visit_TupleNode(self, node):
        self.emit_sequence(node, u"()")

    def visit_SetNode(self, node):
        if len(node.subexpr_nodes()) > 0:
            self.emit_sequence(node, u"{}")
        else:
            self.put(u"set()")

    def visit_DictNode(self, node):
        self.emit_sequence(node, u"{}")

    def visit_DictItemNode(self, node):
        self.visit(node.key)
        self.put(u": ")
        self.visit(node.value)

    unop_precedence = {
        'not': 3, '!': 3,
        '+': 11, '-': 11, '~': 11,
    }
    binop_precedence = {
        'or': 1,
        'and': 2,
        # unary: 'not': 3, '!': 3,
        'in': 4, 'not_in': 4, 'is': 4, 'is_not': 4, '<': 4, '<=': 4, '>': 4, '>=': 4, '!=': 4, '==': 4,
        '|': 5,
        '^': 6,
        '&': 7,
        '<<': 8, '>>': 8,
        '+': 9, '-': 9,
        '*': 10, '@': 10, '/': 10, '//': 10, '%': 10,
        # unary: '+': 11, '-': 11, '~': 11
        '**': 12,
    }

    def operator_enter(self, new_prec):
        old_prec = self.precedence[-1]
        if old_prec > new_prec:
            self.put(u"(")
        self.precedence.append(new_prec)

    def operator_exit(self):
        old_prec, new_prec = self.precedence[-2:]
        if old_prec > new_prec:
            self.put(u")")
        self.precedence.pop()

    def visit_NotNode(self, node):
        op = 'not'
        prec = self.unop_precedence[op]
        self.operator_enter(prec)
        self.put(u"not ")
        self.visit(node.operand)
        self.operator_exit()

    def visit_UnopNode(self, node):
        op = node.operator
        prec = self.unop_precedence[op]
        self.operator_enter(prec)
        self.put(u"%s" % node.operator)
        self.visit(node.operand)
        self.operator_exit()

    def visit_BinopNode(self, node):
        op = node.operator
        prec = self.binop_precedence.get(op, 0)
        self.operator_enter(prec)
        self.visit(node.operand1)
        self.put(u" %s " % op.replace('_', ' '))
        self.visit(node.operand2)
        self.operator_exit()

    def visit_BoolBinopNode(self, node):
        self.visit_BinopNode(node)

    def visit_PrimaryCmpNode(self, node):
        self.visit_BinopNode(node)

    def visit_IndexNode(self, node):
        self.visit(node.base)
        self.put(u"[")
        if isinstance(node.index, TupleNode):
            if node.index.subexpr_nodes():
                self.emit_sequence(node.index)
            else:
                self.put(u"()")
        else:
            self.visit(node.index)
        self.put(u"]")

    def visit_SliceIndexNode(self, node):
        self.visit(node.base)
        self.put(u"[")
        if node.start:
            self.visit(node.start)
        self.put(u":")
        if node.stop:
            self.visit(node.stop)
        if node.slice:
            self.put(u":")
            self.visit(node.slice)
        self.put(u"]")

    def visit_SliceNode(self, node):
        if not node.start.is_none:
            self.visit(node.start)
        self.put(u":")
        if not node.stop.is_none:
            self.visit(node.stop)
        if not node.step.is_none:
            self.put(u":")
            self.visit(node.step)

    def visit_CondExprNode(self, node):
        self.visit(node.true_val)
        self.put(u" if ")
        self.visit(node.test)
        self.put(u" else ")
        self.visit(node.false_val)

    def visit_AttributeNode(self, node):
        self.visit(node.obj)
        self.put(u".%s" % node.attribute)

    def visit_SimpleCallNode(self, node):
        self.visit(node.function)
        self.put(u"(")
        self.comma_separated_list(node.args)
        self.put(")")

    def emit_pos_args(self, node):
        if node is None:
            return
        if isinstance(node, AddNode):
            self.emit_pos_args(node.operand1)
            self.emit_pos_args(node.operand2)
        elif isinstance(node, TupleNode):
            for expr in node.subexpr_nodes():
                self.visit(expr)
                self.put(u", ")
        elif isinstance(node, AsTupleNode):
            self.put("*")
            self.visit(node.arg)
            self.put(u", ")
        else:
            self.visit(node)
            self.put(u", ")

    def emit_kwd_args(self, node):
        if node is None:
            return
        if isinstance(node, MergedDictNode):
            for expr in node.subexpr_nodes():
                self.emit_kwd_args(expr)
        elif isinstance(node, DictNode):
            for expr in node.subexpr_nodes():
                self.put(u"%s=" % expr.key.value)
                self.visit(expr.value)
                self.put(u", ")
        else:
            self.put(u"**")
            self.visit(node)
            self.put(u", ")

    def visit_GeneralCallNode(self, node):
        self.visit(node.function)
        self.put(u"(")
        self.emit_pos_args(node.positional_args)
        self.emit_kwd_args(node.keyword_args)
        self.remove(u", ")
        self.put(")")

    def emit_comprehension(self, body, target,
                           sequence, condition,
                           parens=(u"", u"")):
        open_paren, close_paren = parens
        self.put(open_paren)
        self.visit(body)
        self.put(u" for ")
        self.visit(target)
        self.put(u" in ")
        self.visit(sequence)
        if condition:
            self.put(u" if ")
            self.visit(condition)
        self.put(close_paren)

    def visit_ComprehensionAppendNode(self, node):
        self.visit(node.expr)

    def visit_DictComprehensionAppendNode(self, node):
        self.visit(node.key_expr)
        self.put(u": ")
        self.visit(node.value_expr)

    def visit_ComprehensionNode(self, node):
        tpmap = {'list': u"[]", 'dict': u"{}", 'set': u"{}"}
        parens = tpmap[node.type.py_type_name()]
        body = node.loop.body
        target = node.loop.target
        sequence = node.loop.iterator.sequence
        condition = None
        if hasattr(body, 'if_clauses'):
            # type(body) is Nodes.IfStatNode
            condition = body.if_clauses[0].condition
            body = body.if_clauses[0].body
        self.emit_comprehension(body, target, sequence, condition, parens)

    def visit_GeneratorExpressionNode(self, node):
        body = node.loop.body
        target = node.loop.target
        sequence = node.loop.iterator.sequence
        condition = None
        if hasattr(body, 'if_clauses'):
            # type(body) is Nodes.IfStatNode
            condition = body.if_clauses[0].condition
            body = body.if_clauses[0].body.expr.arg
        elif hasattr(body, 'expr'):
            # type(body) is Nodes.ExprStatNode
            body = body.expr.arg
        self.emit_comprehension(body, target, sequence, condition, u"()")