mycpp/cppgen

OILS / mycpp / cppgen_pass.py View on Github | oils.pub

2823 lines, 1770 significant

1	"""
2	cppgen_pass.py - AST pass that prints C++ code
3	"""
4	import itertools
5	import json # for "C escaping"
6
7	from typing import Union, Optional, Dict
8
9	import mypy
10	from mycpp import visitor
11	from mypy.types import (Type, AnyType, NoneTyp, TupleType, Instance,
12	Overloaded, CallableType, UnionType, UninhabitedType,
13	PartialType, TypeAliasType)
14	from mypy.nodes import (Expression, Statement, NameExpr, IndexExpr, MemberExpr,
15	TupleExpr, ExpressionStmt, IfStmt, StrExpr, SliceExpr,
16	FuncDef, UnaryExpr, OpExpr, CallExpr, ListExpr,
17	DictExpr, ClassDef, ForStmt, AssignmentStmt)
18
19	from mycpp import format_strings
20	from mycpp import pass_state
21	from mycpp import util
22	from mycpp.util import log, SymbolToString, SplitPyName
23
24	from typing import Tuple, List, Any, TYPE_CHECKING
25	if TYPE_CHECKING:
26	from mycpp import const_pass
27	from mycpp import conversion_pass
28
29
30	def _IsContextManager(class_name: util.SymbolPath) -> bool:
31	return class_name[-1].startswith('ctx_')
32
33
34	def _GetCTypeForCast(type_expr: Expression) -> str:
35	""" MyPy cast() """
36
37	if isinstance(type_expr, MemberExpr):
38	left = type_expr.expr
39	assert isinstance(left, NameExpr), left # assume it's module.Type
40	subtype_name = '%s::%s' % (left.name, type_expr.name)
41	elif isinstance(type_expr, IndexExpr):
42	# List[word_t] would be a problem.
43	# But worked around it in osh/word_parse.py
44	#subtype_name = 'List<word_t>'
45	raise AssertionError()
46	elif isinstance(type_expr, StrExpr):
47	parts = type_expr.value.split('.')
48	subtype_name = '::'.join(parts)
49	elif isinstance(type_expr, NameExpr):
50	subtype_name = type_expr.name
51	else:
52	raise AssertionError()
53
54	# Hack for now
55	if subtype_name != 'int' and subtype_name != 'mops::BigInt':
56	subtype_name += '*'
57	return subtype_name
58
59
60	def _GetCastKind(module_path: str, cast_to_type: str) -> str:
61	"""Translate MyPy cast to C++ cast.
62
63	Prefer static_cast, but sometimes we need reinterpret_cast.
64	"""
65	cast_kind = 'static_cast'
66
67	# Hack for Id.Expr_CastedDummy in expr_to_ast.py
68	if 'expr_to_ast.py' in module_path:
69	for name in (
70	'ShArrayLiteral',
71	'CommandSub',
72	'BracedVarSub',
73	'DoubleQuoted',
74	'SingleQuoted',
75	# Another kind of hack, not because of CastDummy
76	'y_lhs_t',
77	):
78	if name in cast_to_type:
79	cast_kind = 'reinterpret_cast'
80	break
81
82	# The other side of Id.Expr_CastedDummy
83	if 'expr_parse.py' in module_path:
84	for name in ('Token', ):
85	if name in cast_to_type:
86	cast_kind = 'reinterpret_cast'
87	break
88
89	if 'process.py' in module_path and 'mylib::Writer' in cast_to_type:
90	cast_kind = 'reinterpret_cast'
91
92	return cast_kind
93
94
95	def _ContainsFunc(t: Type) -> Optional[str]:
96	""" x in y """
97	contains_func = None
98
99	if isinstance(t, Instance):
100	type_name = t.type.fullname
101
102	if type_name == 'builtins.list':
103	contains_func = 'list_contains'
104
105	elif type_name == 'builtins.str':
106	contains_func = 'str_contains'
107
108	elif type_name == 'builtins.dict':
109	contains_func = 'dict_contains'
110
111	elif isinstance(t, UnionType):
112	# Special case for Optional[T] == Union[T, None]
113	if len(t.items) != 2:
114	raise NotImplementedError('Expected Optional, got %s' % t)
115
116	if not isinstance(t.items[1], NoneTyp):
117	raise NotImplementedError('Expected Optional, got %s' % t)
118
119	contains_func = _ContainsFunc(t.items[0])
120
121	return contains_func # None checked later
122
123
124	def _EqualsFunc(left_type: Type) -> Optional[str]:
125	if util.IsStr(left_type):
126	return 'str_equals'
127
128	if (isinstance(left_type, UnionType) and len(left_type.items) == 2 and
129	util.IsStr(left_type.items[0]) and
130	isinstance(left_type.items[1], NoneTyp)):
131	return 'maybe_str_equals'
132
133	return None
134
135
136	_EXPLICIT = ('builtins.str', 'builtins.list', 'builtins.dict')
137
138
139	def _CheckCondition(node: Expression, types: Dict[Expression, Type]) -> bool:
140	"""
141	Ban
142	if (mystr)
143	if (mylist)
144	if (mydict)
145
146	They mean non-empty in Python.
147	"""
148	#log('NODE %s', node)
149
150	if isinstance(node, UnaryExpr) and node.op == 'not':
151	return _CheckCondition(node.expr, types)
152
153	if isinstance(node, OpExpr):
154	#log('OpExpr node %s %s', node, dir(node))
155
156	# if x > 0 and not mylist, etc.
157	return (_CheckCondition(node.left, types) and
158	_CheckCondition(node.right, types))
159
160	t = types[node]
161
162	if isinstance(t, Instance):
163	type_name = t.type.fullname
164	if type_name in _EXPLICIT:
165	return False
166
167	elif isinstance(t, UnionType):
168	if len(t.items) == 2 and isinstance(t.items[1], NoneTyp):
169	t2 = t.items[0]
170	assert isinstance(t2, Instance), t2
171	if t2.type.fullname in _EXPLICIT:
172	return False
173
174	return True
175
176
177	def CTypeIsManaged(c_type: str) -> bool:
178	"""For rooting and field masks."""
179	assert c_type != 'void'
180
181	if util.SMALL_STR:
182	if c_type == 'Str':
183	return True
184
185	# int, double, bool, scope_t enums, etc. are not managed
186	return c_type.endswith('*')
187
188
189	def GetCType(t: Type) -> str:
190	"""Recursively translate MyPy type to C++ type."""
191	is_pointer = False
192
193	if isinstance(t, UninhabitedType):
194	# UninhabitedType is used by def e_usage() -> NoReturn
195	# TODO: we could add [[noreturn]] here!
196	c_type = 'void'
197
198	elif isinstance(t, PartialType):
199	# I removed the last instance of this! It was dead code in comp_ui.py.
200	raise AssertionError()
201	#c_type = 'void'
202	#is_pointer = True
203
204	elif isinstance(t,
205	NoneTyp): # e.g. a function that doesn't return anything
206	return 'void'
207
208	elif isinstance(t, AnyType):
209	# 'any' in ASDL becomes void*
210	# It's useful for value::BuiltinFunc(void* f) which is a vm::_Callable*
211	c_type = 'void'
212	is_pointer = True
213
214	elif isinstance(t, CallableType):
215	# Function types are expanded
216	# Callable[[Parser, Token, int], arith_expr_t]
217	# -> arith_expr_t* (f)(Parser, Token*, int) nud;
218
219	ret_type = GetCType(t.ret_type)
220	arg_types = [GetCType(typ) for typ in t.arg_types]
221	c_type = '%s (*f)(%s)' % (ret_type, ', '.join(arg_types))
222
223	elif isinstance(t, TypeAliasType):
224	if 0:
225	log('***')
226	log('%s', t)
227	log('%s', dir(t))
228	log('%s', t.alias)
229	log('%s', dir(t.alias))
230	log('%s', t.alias.target)
231	log('***')
232	return GetCType(t.alias.target)
233
234	elif isinstance(t, Instance):
235	type_name = t.type.fullname
236	#log('** TYPE NAME %s', type_name)
237
238	if type_name == 'builtins.int':
239	c_type = 'int'
240
241	elif type_name == 'builtins.float':
242	c_type = 'double'
243
244	elif type_name == 'builtins.bool':
245	c_type = 'bool'
246
247	elif type_name == 'builtins.str':
248	if util.SMALL_STR:
249	c_type = 'Str'
250	is_pointer = False
251	else:
252	c_type = 'BigStr'
253	is_pointer = True
254
255	elif 'BigInt' in type_name:
256	# also spelled mycpp.mylib.BigInt
257
258	c_type = 'mops::BigInt'
259	# Not a pointer!
260
261	elif type_name == 'typing.IO':
262	c_type = 'mylib::File'
263	is_pointer = True
264
265	# Parameterized types: List, Dict, Iterator
266	elif type_name == 'builtins.list':
267	assert len(t.args) == 1, t.args
268	type_param = t.args[0]
269	inner_c_type = GetCType(type_param)
270	c_type = 'List<%s>' % inner_c_type
271	is_pointer = True
272
273	elif type_name == 'builtins.dict':
274	params = []
275	for type_param in t.args:
276	params.append(GetCType(type_param))
277	c_type = 'Dict<%s>' % ', '.join(params)
278	is_pointer = True
279
280	elif type_name == 'typing.Iterator':
281	assert len(t.args) == 1, t.args
282	type_param = t.args[0]
283	inner_c_type = GetCType(type_param)
284	c_type = 'ListIter<%s>' % inner_c_type
285
286	else:
287	parts = t.type.fullname.split('.')
288	c_type = '%s::%s' % (parts[-2], parts[-1])
289
290	# note: fullname => 'parse.Lexer'; name => 'Lexer'
291	base_class_names = [b.type.fullname for b in t.type.bases]
292
293	# Check base class for pybase.SimpleObj so we can output
294	# expr_asdl::tok_t instead of expr_asdl::tok_t*. That is a enum, while
295	# expr_t is a "regular base class".
296	# NOTE: Could we avoid the typedef? If it's SimpleObj, just generate
297	# tok_e instead?
298
299	if 'asdl.pybase.SimpleObj' not in base_class_names:
300	is_pointer = True
301
302	elif isinstance(t, TupleType):
303	inner_c_types = [GetCType(inner) for inner in t.items]
304	c_type = 'Tuple%d<%s>' % (len(t.items), ', '.join(inner_c_types))
305	is_pointer = True
306
307	elif isinstance(t, UnionType): # Optional[T]
308
309	num_items = len(t.items)
310
311	if num_items == 3:
312	# Special case for Optional[IOError_OSError] ==
313	# Union[IOError, # OSError, None]
314	t0 = t.items[0]
315	t1 = t.items[1]
316	t2 = t.items[2]
317
318	assert isinstance(t0, Instance), t0
319	assert isinstance(t1, Instance), t1
320	t0_name = t0.type.fullname
321	t1_name = t1.type.fullname
322
323	if t0_name != 'builtins.IOError':
324	raise NotImplementedError(
325	'Expected Union[IOError, OSError, None]: t0 = %s' %
326	t0_name)
327
328	if t1_name != 'builtins.OSError':
329	raise NotImplementedError(
330	'Expected Union[IOError, OSError, None]: t1 = %s' %
331	t1_name)
332
333	if not isinstance(t2, NoneTyp):
334	raise NotImplementedError(
335	'Expected Union[IOError, OSError, None]')
336
337	c_type = 'IOError_OSError'
338	is_pointer = True
339
340	elif num_items == 2:
341	# Optional[T]
342
343	t0 = t.items[0]
344	t1 = t.items[1]
345
346	c_type = None
347	if isinstance(t1, NoneTyp):
348	c_type = GetCType(t.items[0])
349	else:
350	assert isinstance(t0, Instance), t0
351	assert isinstance(t1, Instance), t1
352
353	# Detect type alias defined in core/error.py
354	# IOError_OSError = Union[IOError, OSError]
355	t0_name = t0.type.fullname
356	t1_name = t1.type.fullname
357	if (t0_name == 'builtins.IOError' and
358	t1_name == 'builtins.OSError'):
359	c_type = 'IOError_OSError'
360	is_pointer = True
361
362	if c_type is None:
363	raise NotImplementedError('Unexpected Union type %s' % t)
364
365	else:
366	raise NotImplementedError(
367	'Expected 2 or 3 items in Union, got %s' % num_items)
368
369	else:
370	raise NotImplementedError('MyPy type: %s %s' % (type(t), t))
371
372	if is_pointer:
373	c_type += '*'
374
375	return c_type
376
377
378	def GetCReturnType(t: Type) -> Tuple[str, bool, Optional[str]]:
379	"""
380	Returns a C string, whether the tuple-by-value optimization was applied,
381	and the C type of an extra output param if the function is a generator.
382	"""
383
384	c_ret_type = GetCType(t)
385
386	# Optimization: Return tuples BY VALUE
387	if isinstance(t, TupleType):
388	assert c_ret_type.endswith('*')
389	return c_ret_type[:-1], True, None
390	elif c_ret_type.startswith('ListIter<'):
391	assert len(t.args) == 1, t.args
392	inner_c_type = GetCType(t.args[0])
393	return 'void', False, 'List<%s>*' % inner_c_type
394	else:
395	return c_ret_type, False, None
396
397
398	def PythonStringLiteral(s: str) -> str:
399	"""
400	Returns a properly quoted string.
401	"""
402	# MyPy does bad escaping. Decode and push through json to get something
403	# workable in C++.
404	return json.dumps(format_strings.DecodeMyPyString(s))
405
406
407	def _GetNoReturn(func_name: str) -> str:
408	# Avoid C++ warnings by prepending [[noreturn]]
409	if func_name in ('e_die', 'e_die_status', 'e_strict', 'e_usage', 'p_die'):
410	return '[[noreturn]] '
411	else:
412	return ''
413
414
415	# name, type, is_param
416	LocalVar = Tuple[str, Type, bool]
417
418	# lval_type, c_type, is_managed
419	MemberVar = Tuple[Type, str, bool]
420
421	AllMemberVars = Dict[ClassDef, Dict[str, MemberVar]]
422
423	AllLocalVars = Dict[FuncDef, List[Tuple[str, Type]]]
424
425
426	class _Shared(visitor.TypedVisitor):
427
428	def __init__(
429	self,
430	types: Dict[Expression, Type],
431	global_strings: 'const_pass.GlobalStrings',
432	yield_out_params: Dict[FuncDef, Tuple[str, str]], # input
433	# all_member_vars:
434	# - Decl for declaring members in class { }
435	# - Impl for rooting context managers
436	all_member_vars: Optional[AllMemberVars] = None,
437	) -> None:
438	visitor.TypedVisitor.__init__(self, types)
439	self.global_strings = global_strings
440	self.yield_out_params = yield_out_params
441	self.all_member_vars = all_member_vars # for class def, and rooting
442
443	# Primitives shared for default values
444
445	def visit_int_expr(self, o: 'mypy.nodes.IntExpr') -> None:
446	self.write(str(o.value))
447
448	def visit_float_expr(self, o: 'mypy.nodes.FloatExpr') -> None:
449	# e.g. for arg.t > 0.0
450	self.write(str(o.value))
451
452	def visit_str_expr(self, o: 'mypy.nodes.StrExpr') -> None:
453	self.write(self.global_strings.GetVarName(o))
454
455	def oils_visit_name_expr(self, o: 'mypy.nodes.NameExpr') -> None:
456	if o.name == 'None':
457	self.write('nullptr')
458	return
459	if o.name == 'True':
460	self.write('true')
461	return
462	if o.name == 'False':
463	self.write('false')
464	return
465	if o.name == 'self':
466	self.write('this')
467	return
468
469	self.write(o.name)
470
471	def visit_unary_expr(self, o: 'mypy.nodes.UnaryExpr') -> None:
472	# e.g. a[-1] or 'not x'
473	if o.op == 'not':
474	op_str = '!'
475	else:
476	op_str = o.op
477	self.write(op_str)
478	self.accept(o.expr)
479
480	def _NamespaceComment(self) -> str:
481	# abstract method
482	raise NotImplementedError()
483
484	def oils_visit_mypy_file(self, o: 'mypy.nodes.MypyFile') -> None:
485	mod_parts = o.fullname.split('.')
486	comment = self._NamespaceComment()
487
488	self.write_ind('namespace %s { // %s\n', mod_parts[-1], comment)
489	self.write('\n')
490
491	#self.log('defs %s', o.defs)
492	for node in o.defs:
493	self.accept(node)
494
495	self.write('\n')
496	self.write_ind('} // %s namespace %s\n', comment, mod_parts[-1])
497	self.write('\n')
498
499	def _WriteFuncParams(self,
500	func_def: FuncDef,
501	write_defaults: bool = False) -> None:
502	"""Write params for function/method signatures."""
503	arg_types = func_def.type.arg_types
504	arguments = func_def.arguments
505
506	is_first = True # EXCLUDING 'self'
507	for arg_type, arg in zip(arg_types, arguments):
508	if not is_first:
509	self.write(', ')
510
511	c_type = GetCType(arg_type)
512
513	arg_name = arg.variable.name
514
515	# C++ has implicit 'this'
516	if arg_name == 'self':
517	continue
518
519	# int foo
520	self.write('%s %s', c_type, arg_name)
521
522	if write_defaults and arg.initializer: # int foo = 42
523	self.write(' = ')
524	self.accept(arg.initializer)
525
526	is_first = False
527
528	if 0:
529	self.log('Argument %s', arg.variable)
530	self.log(' type_annotation %s', arg.type_annotation)
531	# I think these are for default values
532	self.log(' initializer %s', arg.initializer)
533	self.log(' kind %s', arg.kind)
534
535	# Is the function we're writing params for an iterator?
536	if func_def in self.yield_out_params:
537	self.write(', ')
538
539	arg_name, c_type = self.yield_out_params[func_def]
540	self.write('%s %s', c_type, arg_name)
541
542
543	class Decl(_Shared):
544
545	def __init__(
546	self,
547	types: Dict[Expression, Type],
548	global_strings: 'const_pass.GlobalStrings',
549	yield_out_params: Dict[FuncDef, Tuple[str, str]], # input
550	virtual: pass_state.Virtual = None,
551	all_member_vars: Optional[AllMemberVars] = None,
552	) -> None:
553	_Shared.__init__(
554	self,
555	types,
556	global_strings,
557	yield_out_params,
558	all_member_vars=all_member_vars,
559	)
560	self.virtual = virtual
561
562	def _NamespaceComment(self) -> str:
563	# abstract method
564	return 'declare'
565
566	def oils_visit_func_def(self, o: 'mypy.nodes.FuncDef') -> None:
567	# Avoid C++ warnings by prepending [[noreturn]]
568	noreturn = _GetNoReturn(o.name)
569
570	virtual = ''
571	if self.virtual.IsVirtual(self.current_class_name, o.name):
572	virtual = 'virtual '
573
574	# declaration inside class { }
575	func_name = o.name
576
577	# Why can't we get this Type object with self.types[o]?
578	c_ret_type, _, _ = GetCReturnType(o.type.ret_type)
579
580	self.write_ind('%s%s%s %s(', noreturn, virtual, c_ret_type, func_name)
581
582	self._WriteFuncParams(o, write_defaults=True)
583	self.write(');\n')
584
585	def oils_visit_member_expr(self, o: 'mypy.nodes.MemberExpr') -> None:
586	# In declarations, 'a.b' is only used for default argument
587	# values 'a::b'
588	self.accept(o.expr)
589	# TODO: remove write() in Decl pass
590	self.write('::')
591	self.write(o.name)
592
593	def oils_visit_assignment_stmt(self, o: 'mypy.nodes.AssignmentStmt',
594	lval: Expression, rval: Expression) -> None:
595	# Declare constant strings. They have to be at the top level.
596
597	# TODO: self.at_global_scope doesn't work for context managers and so forth
598	if self.indent == 0:
599	# Top level can't have foo.bar = baz
600	assert isinstance(lval, NameExpr), lval
601	if not util.SkipAssignment(lval.name):
602	c_type = GetCType(self.types[lval])
603	self.write('extern %s %s;\n', c_type, lval.name)
604
605	# TODO: we don't traverse here, so _CheckCondition() isn't called
606	# e.g. x = 'a' if mylist else 'b'
607
608	def oils_visit_constructor(self, o: ClassDef, stmt: FuncDef,
609	base_class_sym: util.SymbolPath) -> None:
610	self.indent += 1
611	self.write_ind('%s(', o.name)
612	self._WriteFuncParams(stmt, write_defaults=True)
613	self.write(');\n')
614	self.indent -= 1
615
616	def oils_visit_dunder_exit(self, o: ClassDef, stmt: FuncDef,
617	base_class_sym: util.SymbolPath) -> None:
618	self.indent += 1
619	# Turn it into a destructor with NO ARGS
620	self.write_ind('~%s();\n', o.name)
621	self.indent -= 1
622
623	def oils_visit_method(self, o: ClassDef, stmt: FuncDef,
624	base_class_sym: util.SymbolPath) -> None:
625	self.indent += 1
626	self.accept(stmt)
627	self.indent -= 1
628
629	def oils_visit_class_members(self, o: ClassDef,
630	base_class_sym: util.SymbolPath) -> None:
631	# Write member variables
632	self.indent += 1
633	self._MemberDecl(o, base_class_sym)
634	self.indent -= 1
635
636	def oils_visit_class_def(
637	self, o: 'mypy.nodes.ClassDef',
638	base_class_sym: Optional[util.SymbolPath]) -> None:
639	self.write_ind('class %s', o.name) # block after this
640
641	# e.g. class TextOutput : public ColorOutput
642	if base_class_sym:
643	self.write(' : public %s',
644	SymbolToString(base_class_sym, strip_package=True))
645
646	self.write(' {\n')
647	self.write_ind(' public:\n')
648
649	# This visits all the methods, with self.indent += 1, param
650	# base_class_sym, self.current_method_name
651
652	super().oils_visit_class_def(o, base_class_sym)
653
654	self.write_ind('};\n')
655	self.write('\n')
656
657	def _GcHeaderDecl(self, o: 'mypy.nodes.ClassDef',
658	field_gc: Tuple[str, str], mask_bits: List[str]) -> None:
659	if mask_bits:
660	self.write_ind('\n')
661	self.write_ind('static constexpr uint32_t field_mask() {\n')
662	self.write_ind(' return ')
663	for i, b in enumerate(mask_bits):
664	if i != 0:
665	self.write('\n')
666	self.write_ind(' \| ')
667	self.write(b)
668	self.write(';\n')
669	self.write_ind('}\n')
670
671	obj_tag, obj_arg = field_gc
672	if obj_tag == 'HeapTag::FixedSize':
673	obj_mask = obj_arg
674	obj_header = 'ObjHeader::ClassFixed(%s, sizeof(%s))' % (obj_mask,
675	o.name)
676	elif obj_tag == 'HeapTag::Scanned':
677	num_pointers = obj_arg
678	obj_header = 'ObjHeader::ClassScanned(%s, sizeof(%s))' % (
679	num_pointers, o.name)
680	else:
681	raise AssertionError(o.name)
682
683	self.write('\n')
684	self.write_ind('static constexpr ObjHeader obj_header() {\n')
685	self.write_ind(' return %s;\n' % obj_header)
686	self.write_ind('}\n')
687
688	def _MemberDecl(self, o: 'mypy.nodes.ClassDef',
689	base_class_sym: util.SymbolPath) -> None:
690	member_vars = self.all_member_vars[o]
691
692	# List of field mask expressions
693	mask_bits = []
694	if self.virtual.CanReorderFields(SplitPyName(o.fullname)):
695	# No inheritance, so we are free to REORDER member vars, putting
696	# pointers at the front.
697
698	pointer_members = []
699	non_pointer_members = []
700
701	for name in member_vars:
702	_, c_type, is_managed = member_vars[name]
703	if is_managed:
704	pointer_members.append(name)
705	else:
706	non_pointer_members.append(name)
707
708	# So we declare them in the right order
709	sorted_member_names = pointer_members + non_pointer_members
710
711	field_gc = ('HeapTag::Scanned', str(len(pointer_members)))
712	else:
713	# Has inheritance
714
715	# The field mask of a derived class is unioned with its base's
716	# field mask.
717	if base_class_sym:
718	mask_bits.append(
719	'%s::field_mask()' %
720	SymbolToString(base_class_sym, strip_package=True))
721
722	for name in sorted(member_vars):
723	_, c_type, is_managed = member_vars[name]
724	if is_managed:
725	mask_bits.append('maskbit(offsetof(%s, %s))' %
726	(o.name, name))
727
728	# A base class with no fields has kZeroMask.
729	if not base_class_sym and not mask_bits:
730	mask_bits.append('kZeroMask')
731
732	sorted_member_names = sorted(member_vars)
733
734	field_gc = ('HeapTag::FixedSize', 'field_mask()')
735
736	# Write member variables
737
738	#log('MEMBERS for %s: %s', o.name, list(self.member_vars.keys()))
739	if len(member_vars):
740	if base_class_sym:
741	self.write('\n') # separate from functions
742
743	for name in sorted_member_names:
744	_, c_type, _ = member_vars[name]
745	# use default zero initialization for all members
746	# (context managers may be on the stack)
747	self.write_ind('%s %s{};\n', c_type, name)
748
749	# Context managers aren't GC objects
750	if not _IsContextManager(self.current_class_name):
751	self._GcHeaderDecl(o, field_gc, mask_bits)
752
753	self.write('\n')
754	self.write_ind('DISALLOW_COPY_AND_ASSIGN(%s)\n', o.name)
755
756
757	class Impl(_Shared):
758
759	def __init__(
760	self,
761	types: Dict[Expression, Type],
762	global_strings: 'const_pass.GlobalStrings',
763	yield_out_params: Dict[FuncDef, Tuple[str, str]], # input
764	all_member_vars: Optional[AllMemberVars] = None,
765	local_vars: Optional[AllLocalVars] = None,
766	dot_exprs: Optional['conversion_pass.DotExprs'] = None,
767	stack_roots_warn: Optional[int] = None,
768	stack_roots: Optional[pass_state.StackRoots] = None) -> None:
769	_Shared.__init__(self,
770	types,
771	global_strings,
772	yield_out_params,
773	all_member_vars=all_member_vars)
774	self.local_vars = local_vars
775
776	# Computed in previous passes
777	self.dot_exprs = dot_exprs
778	self.stack_roots_warn = stack_roots_warn
779	self.stack_roots = stack_roots
780
781	# Traversal state used to to create an EAGER List<T>
782	self.yield_eager_assign: Dict[AssignmentStmt, Tuple[str, str]] = {}
783	self.yield_eager_for: Dict[ForStmt, Tuple[str, str]] = {}
784
785	self.yield_assign_node: Optional[AssignmentStmt] = None
786	self.yield_for_node: Optional[ForStmt] = None
787
788	# More Traversal state
789	self.current_func_node: Optional[FuncDef] = None
790
791	self.unique_id = 0
792
793	def _NamespaceComment(self) -> str:
794	# abstract method
795	return 'define'
796
797	def oils_visit_func_def(self, o: 'mypy.nodes.FuncDef') -> None:
798	if self.current_class_name:
799	# definition looks like
800	# void Class::method(...);
801	func_name = SymbolToString((self.current_class_name[-1], o.name))
802	noreturn = ''
803	else:
804	func_name = o.name
805	noreturn = _GetNoReturn(o.name)
806
807	self.write('\n')
808
809	# Why can't we get this Type object with self.types[o]?
810	c_ret_type, _, _ = GetCReturnType(o.type.ret_type)
811
812	self.write_ind('%s%s %s(', noreturn, c_ret_type, func_name)
813
814	self.current_func_node = o
815	self._WriteFuncParams(o, write_defaults=False)
816
817	self.write(') ')
818	arg_names = [arg.variable.name for arg in o.arguments]
819	#log('arg_names %s', arg_names)
820	#log('local_vars %s', self.local_vars[o])
821	local_var_list: List[LocalVar] = []
822	for (lval_name, lval_type) in self.local_vars[o]:
823	local_var_list.append((lval_name, lval_type, lval_name
824	in arg_names))
825
826	self.write('{\n')
827
828	self.indent += 1
829	self._WriteLocals(local_var_list)
830	self._WriteBody(o.body.body)
831	self.indent -= 1
832
833	self.write('}\n')
834
835	self.current_func_node = None
836
837	def visit_yield_expr(self, o: 'mypy.nodes.YieldExpr') -> None:
838	assert self.current_func_node in self.yield_out_params
839	self.write('%s->append(',
840	self.yield_out_params[self.current_func_node][0])
841	self.accept(o.expr)
842	self.write(')')
843
844	def _WriteArgList(self, args: List[Expression]) -> None:
845	self.write('(')
846	for i, arg in enumerate(args):
847	if i != 0:
848	self.write(', ')
849	self.accept(arg)
850
851	# Pass an extra arg like my_generator(42, &accum)
852	#
853	# Two cases:
854	# ForStmt: for y in generator(42): =>
855	# generator(42, &y)
856	# AssignmentStmt: it = generator(42) =>
857	# List<int> _iter_buf_it;
858	# generator(42, &iter_buf_it); # eagerly append
859
860	eager_pair = (self.yield_eager_assign.get(self.yield_assign_node) or
861	self.yield_eager_for.get(self.yield_for_node))
862
863	if eager_pair:
864	if len(args) > 0:
865	self.write(', ')
866
867	eager_list_name, _ = eager_pair
868	self.write('&%s', eager_list_name)
869
870	self.write(')')
871
872	def oils_visit_member_expr(self, o: 'mypy.nodes.MemberExpr') -> None:
873	dot_expr = self.dot_exprs[o]
874
875	if isinstance(dot_expr, pass_state.StackObjectMember):
876	op = '.'
877
878	elif (isinstance(dot_expr, pass_state.StaticClassMember) or
879	isinstance(dot_expr, pass_state.ModuleMember)):
880	op = '::'
881
882	elif isinstance(dot_expr, pass_state.HeapObjectMember):
883	op = '->'
884
885	else:
886	raise AssertionError()
887
888	self.accept(o.expr)
889	self.write(op)
890
891	if o.name == 'errno':
892	# e->errno -> e->errno_ to avoid conflict with C macro
893	self.write('errno_')
894	else:
895	self.write('%s', o.name)
896
897	def _IsInstantiation(self, o: 'mypy.nodes.CallExpr') -> bool:
898	callee_name = o.callee.name
899	callee_type = self.types[o.callee]
900
901	# e.g. int() takes str, float, etc. It doesn't matter for translation.
902	if isinstance(callee_type, Overloaded):
903	if 0:
904	for item in callee_type.items():
905	self.log('item: %s', item)
906
907	if isinstance(callee_type, CallableType):
908	# If the function name is the same as the return type, then add
909	# 'Alloc<>'. f = Foo() => f = Alloc<Foo>().
910	ret_type = callee_type.ret_type
911
912	# e.g. str(i) is a free function
913	if (callee_name not in ('str', 'bool', 'float') and
914	'BigInt' not in callee_name and
915	isinstance(ret_type, Instance)):
916
917	ret_type_name = ret_type.type.name
918
919	# HACK: Const is the callee; expr__Const is the return type
920	if (ret_type_name == callee_name or
921	ret_type_name.endswith('__' + callee_name)):
922	return True
923
924	return False
925
926	def oils_visit_probe_call(self, o: 'mypy.nodes.CallExpr') -> None:
927	assert len(o.args) >= 2 and len(o.args) < 13, o.args
928	assert isinstance(o.args[0], mypy.nodes.StrExpr), o.args[0]
929	assert isinstance(o.args[1], mypy.nodes.StrExpr), o.args[1]
930	arity = len(o.args) - 2
931	macro = 'DTRACE_PROBE'
932	if arity > 0:
933	macro = 'DTRACE_PROBE%d' % arity
934
935	self.write('%s(%s, %s', macro, o.args[0].value, o.args[1].value)
936
937	for arg in o.args[2:]:
938	arg_type = self.types[arg]
939	self.write(', ')
940	if util.IsStr(arg_type): # TODO: doesn't know it's an Instance
941	self.write('%s->data()' % arg.name)
942	else:
943	self.accept(arg)
944
945	self.write(')')
946
947	def oils_visit_log_call(self, fmt: StrExpr,
948	args: List[Expression]) -> None:
949	if len(args) == 0: # log('const') -> print_stderr(S_xyz)
950	# This is a GC string
951	self.write('mylib::print_stderr(')
952	self.accept(fmt)
953	self.write(')')
954	return
955
956	# log('const %s', a) -> print_stderr(StrFormat("const %s", a))
957	quoted_fmt = PythonStringLiteral(fmt.value)
958	self.write('mylib::print_stderr(StrFormat(%s, ' % quoted_fmt)
959
960	for i, arg in enumerate(args):
961	if i != 0:
962	self.write(', ')
963	self.accept(arg)
964	self.write('))')
965
966	def oils_visit_call_expr(self, o: 'mypy.nodes.CallExpr') -> None:
967	callee_name = o.callee.name
968
969	# return cast(ShArrayLiteral, tok)
970	# -> return static_cast<ShArrayLiteral*>(tok)
971
972	# TODO: Consolidate this with AssignmentExpr logic.
973	if callee_name == 'cast':
974	call = o
975	type_expr = call.args[0]
976
977	subtype_name = _GetCTypeForCast(type_expr)
978	cast_kind = _GetCastKind(self.module_path, subtype_name)
979	self.write('%s<%s>(', cast_kind, subtype_name)
980	self.accept(call.args[1]) # variable being casted
981	self.write(')')
982	return
983
984	if isinstance(o.callee, MemberExpr) and callee_name == 'next':
985	self.accept(o.callee.expr)
986	self.write('.iterNext')
987	self._WriteArgList(o.args)
988	return
989
990	if self._IsInstantiation(o):
991	self.write('Alloc<')
992	self.accept(o.callee)
993	self.write('>')
994	self._WriteArgList(o.args)
995	return
996
997	# Namespace.
998	if callee_name == 'int': # int('foo') in Python conflicts with keyword
999	self.write('to_int')
1000	elif callee_name == 'float':
1001	self.write('to_float')
1002	elif callee_name == 'bool':
1003	self.write('to_bool')
1004	else:
1005	self.accept(o.callee) # could be f() or obj.method()
1006
1007	self._WriteArgList(o.args)
1008
1009	# TODO: we could check that keyword arguments are passed as named args?
1010	#self.log(' arg_kinds %s', o.arg_kinds)
1011	#self.log(' arg_names %s', o.arg_names)
1012
1013	def oils_visit_format_expr(self, left: Expression,
1014	right: Expression) -> None:
1015	self.write('StrFormat(')
1016	if isinstance(left, StrExpr):
1017	self.write(PythonStringLiteral(left.value))
1018	else:
1019	self.accept(left)
1020	#log('right_type %s', right_type)
1021
1022	right_type = self.types[right]
1023
1024	# TODO: Can we restore some type checking?
1025	if 0:
1026	if isinstance(right_type, Instance):
1027	fmt_types: List[Type] = [right_type]
1028	elif isinstance(right_type, TupleType):
1029	fmt_types = right_type.items
1030	# Handle Optional[str]
1031	elif (isinstance(right_type, UnionType) and
1032	len(right_type.items) == 2 and
1033	isinstance(right_type.items[1], NoneTyp)):
1034	fmt_types = [right_type.items[0]]
1035	else:
1036	raise AssertionError(right_type)
1037
1038	# In the definition pass, write the call site.
1039	if isinstance(right_type, TupleType):
1040	assert isinstance(right, TupleExpr), right
1041	for i, item in enumerate(right.items):
1042	self.write(', ')
1043	self.accept(item)
1044
1045	else: # '[%s]' % x
1046	self.write(', ')
1047	self.accept(right)
1048
1049	self.write(')')
1050
1051	def oils_visit_op_expr(self, o: 'mypy.nodes.OpExpr') -> None:
1052	# a + b when a and b are strings. (Can't use operator overloading
1053	# because they're pointers.)
1054	left_type = self.types[o.left]
1055	right_type = self.types[o.right]
1056
1057	# NOTE: Need GetCType to handle Optional[BigStr*] in ASDL schemas.
1058	# Could tighten it up later.
1059	left_ctype = GetCType(left_type)
1060	right_ctype = GetCType(right_type)
1061
1062	c_op = o.op
1063	if left_ctype == right_ctype == 'int' and c_op == '//':
1064	# integer division // -> /
1065	c_op = '/'
1066
1067	# 'abc' + 'def'
1068	if left_ctype == right_ctype == 'BigStr*' and c_op == '+':
1069	self.write('str_concat(')
1070	self.accept(o.left)
1071	self.write(', ')
1072	self.accept(o.right)
1073	self.write(')')
1074	return
1075
1076	# 'abc' * 3
1077	if left_ctype == 'BigStr' and right_ctype == 'int' and c_op == '':
1078	self.write('str_repeat(')
1079	self.accept(o.left)
1080	self.write(', ')
1081	self.accept(o.right)
1082	self.write(')')
1083	return
1084
1085	# [None] * 3 => list_repeat(None, 3)
1086	if (left_ctype.startswith('List<') and right_ctype == 'int' and
1087	c_op == '*'):
1088	self.write('list_repeat(')
1089	self.accept(o.left.items[0])
1090	self.write(', ')
1091	self.accept(o.right)
1092	self.write(')')
1093	return
1094
1095	# These parens are sometimes extra, but sometimes required. Example:
1096	#
1097	# if ((a and (false or true))) { # right
1098	# vs.
1099	# if (a and false or true)) { # wrong
1100	self.write('(')
1101	self.accept(o.left)
1102	self.write(' %s ', c_op)
1103	self.accept(o.right)
1104	self.write(')')
1105
1106	def visit_comparison_expr(self, o: 'mypy.nodes.ComparisonExpr') -> None:
1107	# Make sure it's binary
1108	assert len(o.operators) == 1, o.operators
1109	assert len(o.operands) == 2, o.operands
1110
1111	operator = o.operators[0]
1112	left = o.operands[0]
1113	right = o.operands[1]
1114
1115	# Assume is and is not are for None / nullptr comparison.
1116	if operator == 'is': # foo is None => foo == nullptr
1117	self.accept(o.operands[0])
1118	self.write(' == ')
1119	self.accept(o.operands[1])
1120	return
1121
1122	if operator == 'is not': # foo is not None => foo != nullptr
1123	self.accept(o.operands[0])
1124	self.write(' != ')
1125	self.accept(o.operands[1])
1126	return
1127
1128	t0 = self.types[left]
1129	t1 = self.types[right]
1130
1131	# 0: not a special case
1132	# 1: str
1133	# 2: Optional[str] which is Union[str, None]
1134	left_type_i = 0 # not a special case
1135	right_type_i = 0 # not a special case
1136
1137	if util.IsStr(t0):
1138	left_type_i = 1
1139	elif (isinstance(t0, UnionType) and len(t0.items) == 2 and
1140	util.IsStr(t0.items[0]) and isinstance(t0.items[1], NoneTyp)):
1141	left_type_i = 2
1142
1143	if util.IsStr(t1):
1144	right_type_i = 1
1145	elif (isinstance(t1, UnionType) and len(t1.items) == 2 and
1146	util.IsStr(t1.items[0]) and isinstance(t1.items[1], NoneTyp)):
1147	right_type_i = 2
1148
1149	#self.log('left_type_i %s right_type_i %s', left_type, right_type)
1150
1151	if left_type_i > 0 and right_type_i > 0 and operator in ('==', '!='):
1152	if operator == '!=':
1153	self.write('!(')
1154
1155	# NOTE: This could also be str_equals(left, right)? Does it make a
1156	# difference?
1157	if left_type_i > 1 or right_type_i > 1:
1158	self.write('maybe_str_equals(')
1159	else:
1160	self.write('str_equals(')
1161	self.accept(left)
1162	self.write(', ')
1163	self.accept(right)
1164	self.write(')')
1165
1166	if operator == '!=':
1167	self.write(')')
1168	return
1169
1170	# Note: we could get rid of this altogether and rely on C++ function
1171	# overloading. But somehow I like it more explicit, closer to C (even
1172	# though we use templates).
1173	contains_func = _ContainsFunc(t1)
1174
1175	if operator == 'in':
1176	if isinstance(right, TupleExpr):
1177	left_type = self.types[left]
1178
1179	equals_func = _EqualsFunc(left_type)
1180
1181	# x in (1, 2, 3) => (x == 1 \|\| x == 2 \|\| x == 3)
1182	self.write('(')
1183
1184	for i, item in enumerate(right.items):
1185	if i != 0:
1186	self.write(' \|\| ')
1187
1188	if equals_func:
1189	self.write('%s(' % equals_func)
1190	self.accept(left)
1191	self.write(', ')
1192	self.accept(item)
1193	self.write(')')
1194	else:
1195	self.accept(left)
1196	self.write(' == ')
1197	self.accept(item)
1198
1199	self.write(')')
1200	return
1201
1202	assert contains_func, "RHS of 'in' has type %r" % t1
1203	# x in mylist => list_contains(mylist, x)
1204	self.write('%s(', contains_func)
1205	self.accept(right)
1206	self.write(', ')
1207	self.accept(left)
1208	self.write(')')
1209	return
1210
1211	if operator == 'not in':
1212	if isinstance(right, TupleExpr):
1213	left_type = self.types[left]
1214	equals_func = _EqualsFunc(left_type)
1215
1216	# x not in (1, 2, 3) => (x != 1 && x != 2 && x != 3)
1217	self.write('(')
1218
1219	for i, item in enumerate(right.items):
1220	if i != 0:
1221	self.write(' && ')
1222
1223	if equals_func:
1224	self.write('!%s(' % equals_func)
1225	self.accept(left)
1226	self.write(', ')
1227	self.accept(item)
1228	self.write(')')
1229	else:
1230	self.accept(left)
1231	self.write(' != ')
1232	self.accept(item)
1233
1234	self.write(')')
1235	return
1236
1237	assert contains_func, t1
1238
1239	# x not in mylist => !list_contains(mylist, x)
1240	self.write('!%s(', contains_func)
1241	self.accept(right)
1242	self.write(', ')
1243	self.accept(left)
1244	self.write(')')
1245	return
1246
1247	# Default case
1248	self.accept(o.operands[0])
1249	self.write(' %s ', o.operators[0])
1250	self.accept(o.operands[1])
1251
1252	def _WriteListElements(self,
1253	items: List[Expression],
1254	sep: str = ', ') -> None:
1255	# sep may be 'COMMA' for a macro
1256	self.write('{')
1257	for i, item in enumerate(items):
1258	if i != 0:
1259	self.write(sep)
1260	self.accept(item)
1261	self.write('}')
1262
1263	def visit_list_expr(self, o: 'mypy.nodes.ListExpr') -> None:
1264	list_type = self.types[o]
1265	# Note: need a lookup function that understands ListExpr -> Instance
1266	assert isinstance(list_type, Instance), list_type
1267
1268	#self.log('**** list_type = %s', list_type)
1269	c_type = GetCType(list_type)
1270
1271	item_type = list_type.args[0] # int for List[int]
1272	item_c_type = GetCType(item_type)
1273
1274	assert c_type.endswith('*'), c_type
1275	c_type = c_type[:-1] # HACK TO CLEAN UP
1276
1277	if len(o.items) == 0:
1278	self.write('Alloc<%s>()' % c_type)
1279	else:
1280	self.write('NewList<%s>(std::initializer_list<%s>' %
1281	(item_c_type, item_c_type))
1282	self._WriteListElements(o.items)
1283	self.write(')')
1284
1285	def visit_dict_expr(self, o: 'mypy.nodes.DictExpr') -> None:
1286	dict_type = self.types[o]
1287	# Note: need a lookup function that understands DictExpr -> Instance
1288	assert isinstance(dict_type, Instance), dict_type
1289
1290	c_type = GetCType(dict_type)
1291	assert c_type.endswith('*'), c_type
1292	c_type = c_type[:-1] # HACK TO CLEAN UP
1293
1294	key_type, val_type = dict_type.args
1295	key_c_type = GetCType(key_type)
1296	val_c_type = GetCType(val_type)
1297
1298	self.write('Alloc<%s>(' % c_type)
1299	#self.write('NewDict<%s, %s>(' % (key_c_type, val_c_type))
1300	if o.items:
1301	keys = [k for k, _ in o.items]
1302	values = [v for _, v in o.items]
1303
1304	self.write('std::initializer_list<%s>' % key_c_type)
1305	self._WriteListElements(keys)
1306	self.write(', ')
1307
1308	self.write('std::initializer_list<%s>' % val_c_type)
1309	self._WriteListElements(values)
1310
1311	self.write(')')
1312
1313	def visit_tuple_expr(self, o: 'mypy.nodes.TupleExpr') -> None:
1314	tuple_type = self.types[o]
1315	c_type = GetCType(tuple_type)
1316	assert c_type.endswith('*'), c_type
1317	c_type = c_type[:-1] # HACK TO CLEAN UP
1318
1319	self.write('(Alloc<%s>(' % c_type)
1320	for i, item in enumerate(o.items):
1321	if i != 0:
1322	self.write(', ')
1323	self.accept(item)
1324	self.write('))')
1325
1326	def visit_index_expr(self, o: 'mypy.nodes.IndexExpr') -> None:
1327	self.accept(o.base)
1328
1329	#base_type = self.types[o.base]
1330	#self.log('*** BASE TYPE %s', base_type)
1331
1332	if isinstance(o.index, SliceExpr):
1333	self.accept(o.index) # method call
1334	else:
1335	# it's hard syntactically to do (*a)[0], so do it this way.
1336	if util.SMALL_STR:
1337	self.write('.at(')
1338	else:
1339	self.write('->at(')
1340
1341	self.accept(o.index)
1342	self.write(')')
1343
1344	def visit_slice_expr(self, o: 'mypy.nodes.SliceExpr') -> None:
1345	self.write('->slice(')
1346	if o.begin_index:
1347	self.accept(o.begin_index)
1348	else:
1349	self.write('0') # implicit beginning
1350
1351	if o.end_index:
1352	self.write(', ')
1353	self.accept(o.end_index)
1354
1355	if o.stride:
1356	if not o.begin_index or not o.end_index:
1357	raise AssertionError(
1358	'Stride only supported with beginning and ending index')
1359
1360	self.write(', ')
1361	self.accept(o.stride)
1362
1363	self.write(')')
1364
1365	def visit_conditional_expr(self, o: 'mypy.nodes.ConditionalExpr') -> None:
1366	if not _CheckCondition(o.cond, self.types):
1367	self.report_error(
1368	o,
1369	"Use explicit len(obj) or 'obj is not None' for mystr, mylist, mydict"
1370	)
1371	return
1372
1373	# 0 if b else 1 -> b ? 0 : 1
1374	self.accept(o.cond)
1375	self.write(' ? ')
1376	self.accept(o.if_expr)
1377	self.write(' : ')
1378	self.accept(o.else_expr)
1379
1380	def _WriteTupleUnpacking(self,
1381	temp_name: str,
1382	lval_items: List[Expression],
1383	item_types: List[Type],
1384	is_return: bool = False) -> None:
1385	"""Used by assignment and for loops.
1386
1387	is_return is a special case for:
1388
1389	# return Tuple2<A, B> by VALUE, not Tuple2<A, B>* pointer
1390	a, b = myfunc()
1391	"""
1392	for i, (lval_item, item_type) in enumerate(zip(lval_items,
1393	item_types)):
1394	if isinstance(lval_item, NameExpr):
1395	if util.SkipAssignment(lval_item.name):
1396	continue
1397	self.write_ind('%s', lval_item.name)
1398	else:
1399	# Could be MemberExpr like self.foo, self.bar = baz
1400	self.write_ind('')
1401	self.accept(lval_item)
1402
1403	# Tuples that are return values aren't pointers
1404	op = '.' if is_return else '->'
1405	self.write(' = %s%sat%d();\n', temp_name, op, i) # RHS
1406
1407	def _WriteTupleUnpackingInLoop(self, temp_name: str,
1408	lval_items: List[Expression],
1409	item_types: List[Type]) -> None:
1410	for i, (lval_item, item_type) in enumerate(zip(lval_items,
1411	item_types)):
1412	c_item_type = GetCType(item_type)
1413
1414	if isinstance(lval_item, NameExpr):
1415	if util.SkipAssignment(lval_item.name):
1416	continue
1417
1418	self.write_ind('%s %s', c_item_type, lval_item.name)
1419	else:
1420	# Could be MemberExpr like self.foo, self.bar = baz
1421	self.write_ind('')
1422	self.accept(lval_item)
1423
1424	op = '->'
1425	self.write(' = %s%sat%d();\n', temp_name, op, i) # RHS
1426
1427	# Note: it would be nice to eliminate these roots, just like
1428	# StackRoots _for() below
1429	if isinstance(lval_item, NameExpr):
1430	if CTypeIsManaged(c_item_type) and not self.stack_roots:
1431	self.write_ind('StackRoot _unpack_%d(&%s);\n' %
1432	(i, lval_item.name))
1433
1434	def _AssignNewDictImpl(self, lval: Expression, prefix: str = '') -> None:
1435	"""Translate NewDict() -> Alloc<Dict<K, V>>
1436
1437	This function is a specal case because the RHS need TYPES from the LHS.
1438
1439	e.g. here is how we make ORDERED dictionaries, which can't be done with {}:
1440
1441	d = NewDict() # type: Dict[int, int]
1442
1443	-> one of
1444
1445	auto* d = Alloc<Dict<int, int>>(); # declare
1446	d = Alloc<Dict<int, int>>(); # mutate
1447
1448	We also have:
1449
1450	self.d = NewDict()
1451	->
1452	this->d = Alloc<Dict<int, int>)();
1453	"""
1454	lval_type = self.types[lval]
1455	#self.log('lval type %s', lval_type)
1456
1457	# Fix for Dict[str, value]? in ASDL
1458	if (isinstance(lval_type, UnionType) and len(lval_type.items) == 2 and
1459	isinstance(lval_type.items[1], NoneTyp)):
1460	lval_type = lval_type.items[0]
1461
1462	c_type = GetCType(lval_type)
1463	assert c_type.endswith('*')
1464	self.write('Alloc<%s>()', c_type[:-1])
1465
1466	def _AssignCastImpl(self, lval: Expression, rval: CallExpr) -> None:
1467	"""
1468	is_downcast_and_shadow idiom:
1469
1470	src = cast(source__SourcedFile, UP_src)
1471	-> source__SourcedFile* src = static_cast<source__SourcedFile>(UP_src)
1472	"""
1473	assert isinstance(lval, NameExpr)
1474	type_expr = rval.args[0]
1475	subtype_name = _GetCTypeForCast(type_expr)
1476
1477	cast_kind = _GetCastKind(self.module_path, subtype_name)
1478
1479	is_downcast_and_shadow = False
1480	to_cast = rval.args[1]
1481	if isinstance(to_cast, NameExpr):
1482	if to_cast.name.startswith('UP_'):
1483	is_downcast_and_shadow = True
1484
1485	if is_downcast_and_shadow:
1486	# Declare NEW local variable inside case, which shadows it
1487	self.write_ind('%s %s = %s<%s>(', subtype_name, lval.name,
1488	cast_kind, subtype_name)
1489	else:
1490	# Normal variable
1491	self.write_ind('%s = %s<%s>(', lval.name, cast_kind, subtype_name)
1492
1493	self.accept(rval.args[1]) # variable being casted
1494	self.write(');\n')
1495
1496	def _AssignToGenerator(self, o: 'mypy.nodes.AssignmentStmt',
1497	lval: Expression, rval_type: Instance) -> None:
1498	"""
1499	it_f = f(42)
1500
1501	translates to
1502
1503	List<int> _iter_buf_it;
1504	f(42, &_iter_buf_it);
1505	"""
1506	# We're calling a generator. Create a temporary List<T> on the stack
1507	# to accumulate the results in one big batch, then wrap it in
1508	# ListIter<T>.
1509	assert len(rval_type.args) == 1, rval_type.args
1510	c_type = GetCType(rval_type)
1511
1512	type_param = rval_type.args[0]
1513	inner_c_type = GetCType(type_param)
1514
1515	assert isinstance(lval, NameExpr), lval
1516	eager_list_name = 'YIELD_%s' % lval.name
1517	eager_list_type = 'List<%s>*' % inner_c_type
1518
1519	# write the variable to accumulate into
1520	self.write_ind('List<%s> %s;\n', inner_c_type, eager_list_name)
1521
1522	# AssignmentStmt key, like:
1523	# it_f = f()
1524	# maybe call them self.generator_func, generator_assign
1525	# In MyPy, the type is Iterator though
1526	self.yield_eager_assign[o] = (eager_list_name, eager_list_type)
1527	self.write_ind('')
1528
1529	self.yield_assign_node = o # AssignmentStmt
1530	self.accept(o.rvalue)
1531	self.yield_assign_node = None
1532
1533	self.write(';\n')
1534
1535	self.write_ind('%s %s(&%s);\n', c_type, lval.name, eager_list_name)
1536
1537	def oils_visit_assign_to_listcomp(self, lval: NameExpr,
1538	left_expr: Expression,
1539	index_expr: Expression, seq: Expression,
1540	cond: Expression) -> None:
1541	"""
1542	Special case for list comprehensions. Note that the LHS MUST be on the
1543	LHS, so we can append to it.
1544
1545	y = [i+1 for i in x[1:] if i]
1546	=>
1547	y = []
1548	for i in x[1:]:
1549	if i:
1550	y.append(i+1)
1551	(but in C++)
1552	"""
1553	self.write_ind('%s = ', lval.name)
1554
1555	# BUG: can't use this to filter
1556	# results = [x for x in results]
1557	if isinstance(seq, NameExpr) and seq.name == lval.name:
1558	raise AssertionError(
1559	"Can't use var %r in list comprehension because it would "
1560	"be overwritten" % lval.name)
1561
1562	c_type = GetCType(self.types[lval])
1563	# Write empty container as initialization.
1564	assert c_type.endswith('*'), c_type # Hack
1565	self.write('Alloc<%s>();\n' % c_type[:-1])
1566
1567	over_type = self.types[seq]
1568	assert isinstance(over_type, Instance), over_type
1569
1570	if over_type.type.fullname == 'builtins.list':
1571	c_type = GetCType(over_type)
1572	# remove *
1573	assert c_type.endswith('*'), c_type
1574	c_iter_type = c_type.replace('List', 'ListIter', 1)[:-1]
1575	else:
1576	# List comprehension over dictionary not implemented
1577	c_iter_type = 'TODO_DICT'
1578
1579	self.write_ind('for (%s it(', c_iter_type)
1580	self.accept(seq)
1581	self.write('); !it.Done(); it.Next()) {\n')
1582
1583	item_type = over_type.args[0] # get 'int' from 'List<int>'
1584
1585	if isinstance(item_type, Instance):
1586	self.write_ind(' %s ', GetCType(item_type))
1587	# TODO(StackRoots): for ch in 'abc'
1588	self.accept(index_expr)
1589	self.write(' = it.Value();\n')
1590
1591	elif isinstance(item_type, TupleType): # [x for x, y in pairs]
1592	c_item_type = GetCType(item_type)
1593
1594	if isinstance(index_expr, TupleExpr):
1595	temp_name = 'tup%d' % self.unique_id
1596	self.unique_id += 1
1597	self.write_ind(' %s %s = it.Value();\n', c_item_type,
1598	temp_name)
1599
1600	self.indent += 1
1601
1602	# list comp
1603	self._WriteTupleUnpackingInLoop(temp_name, index_expr.items,
1604	item_type.items)
1605
1606	self.indent -= 1
1607	else:
1608	raise AssertionError()
1609
1610	else:
1611	raise AssertionError('Unexpected type %s' % item_type)
1612
1613	if cond is not None:
1614	self.indent += 1
1615	self.write_ind('if (')
1616	self.accept(cond)
1617	self.write(') {\n')
1618
1619	self.write_ind(' %s->append(', lval.name)
1620	self.accept(left_expr)
1621	self.write(');\n')
1622
1623	if cond:
1624	self.write_ind('}\n')
1625	self.indent -= 1
1626
1627	self.write_ind('}\n')
1628
1629	def oils_visit_assignment_stmt(self, o: 'mypy.nodes.AssignmentStmt',
1630	lval: Expression, rval: Expression) -> None:
1631
1632	# GLOBAL CONSTANTS - Avoid Alloc<T>, since that can't be done until main().
1633	if self.indent == 0:
1634	assert isinstance(lval, NameExpr), lval
1635	if util.SkipAssignment(lval.name):
1636	return
1637	#self.log(' GLOBAL: %s', lval.name)
1638
1639	lval_type = self.types[lval]
1640
1641	# Global
1642	# L = [1, 2] # type: List[int]
1643	if isinstance(rval, ListExpr):
1644	assert isinstance(lval_type, Instance), lval_type
1645
1646	item_type = lval_type.args[0]
1647	item_c_type = GetCType(item_type)
1648
1649	# Any constant strings will have already been written
1650	# TODO: Assert that every item is a constant?
1651	self.write('GLOBAL_LIST(%s, %s, %d, ', lval.name, item_c_type,
1652	len(rval.items))
1653
1654	self._WriteListElements(rval.items, sep=' COMMA ')
1655
1656	self.write(');\n')
1657	return
1658
1659	# Global
1660	# D = {"foo": "bar"} # type: Dict[str, str]
1661	if isinstance(rval, DictExpr):
1662	assert isinstance(lval_type, Instance), lval_type
1663
1664	key_type, val_type = lval_type.args
1665
1666	key_c_type = GetCType(key_type)
1667	val_c_type = GetCType(val_type)
1668
1669	dict_expr = rval
1670	self.write('GLOBAL_DICT(%s, %s, %s, %d, ', lval.name,
1671	key_c_type, val_c_type, len(dict_expr.items))
1672
1673	keys = [k for k, _ in dict_expr.items]
1674	values = [v for _, v in dict_expr.items]
1675
1676	self._WriteListElements(keys, sep=' COMMA ')
1677	self.write(', ')
1678	self._WriteListElements(values, sep=' COMMA ')
1679
1680	self.write(');\n')
1681	return
1682
1683	# We could do GcGlobal<> for ASDL classes, but Oils doesn't use them
1684	if isinstance(rval, CallExpr):
1685	self.report_error(
1686	o,
1687	"Can't initialize objects at the top level, only BigStr List Dict"
1688	)
1689	return
1690
1691	# myconst = 1 << 3 => myconst = 1 << 3 is currently allowed
1692
1693	#
1694	# Non-top-level
1695	#
1696
1697	if isinstance(rval, CallExpr):
1698	callee = rval.callee
1699	callee_name = callee.name
1700
1701	if callee_name == 'NewDict':
1702	self.write_ind('')
1703
1704	# Hack for non-members - why does this work?
1705	# Tests cases in mycpp/examples/containers.py
1706	if (not isinstance(lval, MemberExpr) and
1707	self.current_func_node is None):
1708	self.write('auto* ')
1709
1710	self.accept(lval)
1711	self.write(' = ')
1712	self._AssignNewDictImpl(lval) # uses lval, not rval
1713	self.write(';\n')
1714	return
1715
1716	if callee_name == 'cast':
1717	self._AssignCastImpl(lval, rval)
1718	return
1719
1720	rval_type = self.types[rval]
1721	if (isinstance(rval_type, Instance) and
1722	rval_type.type.fullname == 'typing.Iterator'):
1723	self._AssignToGenerator(o, lval, rval_type)
1724	return
1725
1726	if isinstance(lval, NameExpr):
1727	lval_type = self.types[lval]
1728	#c_type = GetCType(lval_type, local=self.indent != 0)
1729	c_type = GetCType(lval_type)
1730
1731	if self.at_global_scope:
1732	# globals always get a type -- they're not mutated
1733	self.write_ind('%s %s = ', c_type, lval.name)
1734	else:
1735	# local declarations are "hoisted" to the top of the function
1736	self.write_ind('%s = ', lval.name)
1737
1738	self.accept(rval)
1739	self.write(';\n')
1740	return
1741
1742	if isinstance(lval, MemberExpr): # self.x = foo
1743	self.write_ind('')
1744	self.accept(lval)
1745	self.write(' = ')
1746	self.accept(rval)
1747	self.write(';\n')
1748	return
1749
1750	if isinstance(lval, IndexExpr): # a[x] = 1
1751	# d->set(x, 1) for both List and Dict
1752	self.write_ind('')
1753	self.accept(lval.base)
1754	self.write('->set(')
1755	self.accept(lval.index)
1756	self.write(', ')
1757	self.accept(rval)
1758	self.write(');\n')
1759	return
1760
1761	if isinstance(lval, TupleExpr):
1762	# An assignment to an n-tuple turns into n+1 statements. Example:
1763	#
1764	# x, y = mytuple
1765	#
1766	# Tuple2<int, BigStr*> tup1 = mytuple
1767	# int x = tup1->at0()
1768	# BigStr* y = tup1->at1()
1769
1770	rvalue_type = self.types[rval]
1771
1772	# type alias upgrade for MyPy 0.780
1773	if isinstance(rvalue_type, TypeAliasType):
1774	rvalue_type = rvalue_type.alias.target
1775
1776	assert isinstance(rvalue_type, TupleType), rvalue_type
1777
1778	c_type = GetCType(rvalue_type)
1779
1780	is_return = (isinstance(rval, CallExpr) and
1781	rval.callee.name != "next")
1782	if is_return:
1783	assert c_type.endswith('*')
1784	c_type = c_type[:-1]
1785
1786	temp_name = 'tup%d' % self.unique_id
1787	self.unique_id += 1
1788	self.write_ind('%s %s = ', c_type, temp_name)
1789
1790	self.accept(rval)
1791	self.write(';\n')
1792
1793	# assignment
1794	self._WriteTupleUnpacking(temp_name,
1795	lval.items,
1796	rvalue_type.items,
1797	is_return=is_return)
1798	return
1799
1800	raise AssertionError(lval)
1801
1802	def _WriteBody(self, body: List[Statement]) -> None:
1803	"""Write a block without the { }."""
1804	for stmt in body:
1805	self.accept(stmt)
1806
1807	def oils_visit_for_stmt(self, o: 'mypy.nodes.ForStmt',
1808	func_name: Optional[str]) -> None:
1809	if 0:
1810	self.log('ForStmt')
1811	self.log(' index_type %s', o.index_type)
1812	self.log(' inferred_item_type %s', o.inferred_item_type)
1813	self.log(' inferred_iterator_type %s', o.inferred_iterator_type)
1814
1815	if func_name:
1816	assert isinstance(o.expr, CallExpr), o.expr # caller ensured it
1817	args = o.expr.args
1818
1819	# special case: 'for i in xrange(3)'
1820	if func_name == 'xrange':
1821	assert isinstance(o.index, NameExpr), o.index
1822	index_name = o.index.name
1823
1824	assert isinstance(o.expr, CallExpr), o.expr # caller ensured it
1825	num_args = len(args)
1826
1827	if num_args == 1: # xrange(end)
1828	self.write_ind('for (int %s = 0; %s < ', index_name,
1829	index_name)
1830	self.accept(args[0])
1831	self.write('; ++%s) ', index_name)
1832
1833	elif num_args == 2: # xrange(being, end)
1834	self.write_ind('for (int %s = ', index_name)
1835	self.accept(args[0])
1836	self.write('; %s < ', index_name)
1837	self.accept(args[1])
1838	self.write('; ++%s) ', index_name)
1839
1840	elif num_args == 3: # xrange(being, end, step)
1841	# Special case to detect a step of -1. This is a static
1842	# heuristic, because it could be negative dynamically.
1843	# TODO: could add an API like mylib.reverse_xrange()
1844	step = args[2]
1845	if isinstance(step, UnaryExpr) and step.op == '-':
1846	comparison_op = '>'
1847	else:
1848	comparison_op = '<'
1849
1850	self.write_ind('for (int %s = ', index_name)
1851	self.accept(args[0])
1852	self.write('; %s %s ', index_name, comparison_op)
1853	self.accept(args[1])
1854	self.write('; %s += ', index_name)
1855	self.accept(step)
1856	self.write(') ')
1857
1858	else:
1859	raise AssertionError()
1860
1861	self.accept(o.body)
1862	return
1863
1864	reverse = False
1865
1866	# for i, x in enumerate(...):
1867	index0_name = None
1868	if func_name == 'enumerate':
1869	assert isinstance(o.index, TupleExpr), o.index
1870	index0 = o.index.items[0]
1871
1872	assert isinstance(index0, NameExpr), index0
1873	index0_name = index0.name # generate int i = 0; ; ++i
1874
1875	# Get type of 'x' in 'for i, x in enumerate(...)'
1876	assert isinstance(o.inferred_item_type,
1877	TupleType), o.inferred_item_type
1878	item_type = o.inferred_item_type.items[1]
1879	index_expr = o.index.items[1]
1880
1881	assert isinstance(o.expr, CallExpr), o.expr # caller ensured
1882	# enumerate(mylist) turns into iteration over mylist with variable i
1883	assert len(args) == 1, args
1884	iterated_over = args[0]
1885
1886	elif func_name == 'reversed':
1887	# NOTE: enumerate() and reversed() can't be mixed yet. But you CAN
1888	# reverse iter over tuples.
1889	item_type = o.inferred_item_type
1890	index_expr = o.index
1891
1892	assert len(args) == 1, args
1893	iterated_over = args[0]
1894
1895	reverse = True # use different iterate
1896
1897	elif func_name == 'iteritems':
1898	item_type = o.inferred_item_type
1899	index_expr = o.index
1900
1901	assert len(args) == 1, args
1902	# This should be a dict
1903	iterated_over = args[0]
1904
1905	#log('------------ ITERITEMS OVER %s', iterated_over)
1906
1907	else:
1908	item_type = o.inferred_item_type
1909	index_expr = o.index
1910	iterated_over = o.expr
1911
1912	over_type = self.types[iterated_over]
1913
1914	if isinstance(over_type, TypeAliasType):
1915	over_type = over_type.alias.target
1916
1917	assert isinstance(over_type, Instance), over_type
1918
1919	if 0:
1920	log("***** OVER %s %s", over_type, dir(over_type))
1921	t = over_type.type
1922	log("***** t %s %s", t, dir(t))
1923	bases = t.bases
1924	# Look for string and dict!
1925	log("=== bases %s %s", bases, dir(bases))
1926
1927	#self.log(' iterating over type %s', over_type)
1928	#self.log(' iterating over type %s', over_type.type.fullname)
1929
1930	eager_list_name: Optional[str] = None
1931
1932	over_list = False
1933	over_dict = False
1934
1935	if over_type.type.fullname == 'builtins.list':
1936	over_list = True
1937	container_base_type = over_type
1938
1939	if over_type.type.fullname == 'builtins.dict':
1940	over_dict = True
1941	container_base_type = over_type
1942
1943	# now check base classes
1944	for base_type in over_type.type.bases:
1945	n = base_type.type.fullname
1946	if n == 'builtins.list':
1947	over_list = True
1948	container_base_type = base_type
1949	elif n == 'builtins.dict':
1950	over_dict = True
1951	container_base_type = base_type
1952
1953	assert not (over_dict and over_list)
1954
1955	if over_list:
1956	c_type = GetCType(over_type)
1957	assert c_type.endswith('*'), c_type
1958	inner_c_type = GetCType(container_base_type.args[0])
1959	c_iter_type = 'ListIter<%s>' % inner_c_type
1960
1961	# ReverseListIter!
1962	if reverse:
1963	c_iter_type = 'Reverse' + c_iter_type
1964
1965	elif over_dict:
1966	key_c_type = GetCType(container_base_type.args[0])
1967	val_c_type = GetCType(container_base_type.args[1])
1968	c_iter_type = 'DictIter<%s, %s>' % (key_c_type, val_c_type)
1969	assert not reverse
1970
1971	elif over_type.type.fullname == 'builtins.str':
1972	c_iter_type = 'StrIter'
1973	assert not reverse # can't reverse iterate over string yet
1974
1975	elif over_type.type.fullname == 'typing.Iterator':
1976	# We're iterating over a generator. Create a temporary List<T> on
1977	# the stack to accumulate the results in one big batch.
1978	c_iter_type = GetCType(over_type)
1979
1980	assert len(over_type.args) == 1, over_type.args
1981	inner_c_type = GetCType(over_type.args[0])
1982
1983	# eager_list_name is used below
1984	eager_list_name = 'YIELD_for_%d' % self.unique_id
1985	eager_list_type = 'List<%s>*' % inner_c_type
1986	self.unique_id += 1
1987
1988	self.write_ind('List<%s> %s;\n', inner_c_type, eager_list_name)
1989	self.write_ind('')
1990
1991	# ForStmt - could be self.generator_for_stmt
1992	#
1993	# for x in my_generator(42):
1994	# log('x = %s', x)
1995	#
1996	# Turns into
1997	# List<T> _for_yield_acc3;
1998	# my_generator(42, &_for_yield_acc3);
1999	# for (ListIter it(_for_yield_acc3) ...)
2000
2001	self.yield_eager_for[o] = (eager_list_name, eager_list_type)
2002
2003	self.yield_for_node = o # ForStmt
2004	self.accept(iterated_over)
2005	self.yield_for_node = None
2006
2007	self.write(';\n')
2008
2009	else: # assume it's like d.iteritems()? Iterator type
2010	assert False, over_type
2011
2012	if index0_name:
2013	# can't initialize two things in a for loop, so do it on a separate line
2014	self.write_ind('%s = 0;\n', index0_name)
2015	index_update = ', ++%s' % index0_name
2016	else:
2017	index_update = ''
2018
2019	self.write_ind('for (%s it(', c_iter_type)
2020	if eager_list_name:
2021	self.write('&%s', eager_list_name)
2022	else:
2023	self.accept(iterated_over) # the thing being iterated over
2024	self.write('); !it.Done(); it.Next()%s) {\n', index_update)
2025
2026	# for x in it: ...
2027	# for i, x in enumerate(pairs): ...
2028
2029	if isinstance(item_type, Instance) or index0_name:
2030	c_item_type = GetCType(item_type)
2031	self.write_ind(' %s ', c_item_type)
2032	self.accept(index_expr)
2033	if over_dict:
2034	self.write(' = it.Key();\n')
2035	else:
2036	self.write(' = it.Value();\n')
2037
2038	# Register loop variable as a stack root.
2039	# Note we have mylib.Collect() in CommandEvaluator::_Execute(), and
2040	# it's called in a loop by _ExecuteList(). Although the 'child'
2041	# variable is already live by other means.
2042	# TODO: Test how much this affects performance.
2043	if CTypeIsManaged(c_item_type) and not self.stack_roots:
2044	self.write_ind(' StackRoot _for(&')
2045	self.accept(index_expr)
2046	self.write_ind(');\n')
2047
2048	elif isinstance(item_type, TupleType): # for x, y in pairs
2049	if over_dict:
2050	assert isinstance(o.index, TupleExpr), o.index
2051	index_items = o.index.items
2052	assert len(index_items) == 2, index_items
2053	assert len(item_type.items) == 2, item_type.items
2054
2055	key_type = GetCType(item_type.items[0])
2056	val_type = GetCType(item_type.items[1])
2057
2058	#log('** %s key_type %s', item_type.items[0], key_type)
2059	#log('** %s val_type %s', item_type.items[1], val_type)
2060
2061	assert isinstance(index_items[0], NameExpr), index_items[0]
2062	assert isinstance(index_items[1], NameExpr), index_items[1]
2063
2064	# TODO(StackRoots): k, v
2065	self.write_ind(' %s %s = it.Key();\n', key_type,
2066	index_items[0].name)
2067	self.write_ind(' %s %s = it.Value();\n', val_type,
2068	index_items[1].name)
2069
2070	else:
2071	# Example:
2072	# for (ListIter it(mylist); !it.Done(); it.Next()) {
2073	# Tuple2<int, BigStr*> tup1 = it.Value();
2074	# int i = tup1->at0();
2075	# BigStr* s = tup1->at1();
2076	# log("%d %s", i, s);
2077	# }
2078
2079	c_item_type = GetCType(item_type)
2080
2081	if isinstance(o.index, TupleExpr):
2082	# TODO(StackRoots)
2083	temp_name = 'tup%d' % self.unique_id
2084	self.unique_id += 1
2085	self.write_ind(' %s %s = it.Value();\n', c_item_type,
2086	temp_name)
2087
2088	# loop - for x, y in other:
2089	self.indent += 1
2090	self._WriteTupleUnpackingInLoop(temp_name, o.index.items,
2091	item_type.items)
2092	self.indent -= 1
2093
2094	elif isinstance(o.index, NameExpr):
2095	self.write_ind(' %s %s = it.Value();\n', c_item_type,
2096	o.index.name)
2097	#self.write_ind(' StackRoots _for(&%s)\n;', o.index.name)
2098
2099	else:
2100	raise AssertionError()
2101
2102	else:
2103	raise AssertionError('Unexpected type %s' % item_type)
2104
2105	# Copy of visit_block, without opening {
2106	self.indent += 1
2107	block = o.body
2108	self._WriteBody(block.body)
2109	self.indent -= 1
2110	self.write_ind('}\n')
2111
2112	if o.else_body:
2113	raise AssertionError("can't translate for-else")
2114
2115	def _WriteCases(self, switch_expr: Expression, cases: util.CaseList,
2116	default_block: Union['mypy.nodes.Block', int]) -> None:
2117	""" Write a list of (expr, block) pairs """
2118
2119	for expr, body in cases:
2120	assert expr is not None, expr
2121	if not isinstance(expr, CallExpr):
2122	self.report_error(expr,
2123	'Expected call like case(x), got %s' % expr)
2124	return
2125
2126	for i, arg in enumerate(expr.args):
2127	if i != 0:
2128	self.write('\n')
2129	self.write_ind('case ')
2130	self.accept(arg)
2131	self.write(': ')
2132
2133	self.accept(body)
2134	self.write_ind(' break;\n')
2135
2136	if default_block == -1:
2137	# an error occurred
2138	return
2139	if default_block == -2:
2140	# This is too restrictive
2141	#self.report_error(switch_expr,
2142	# 'switch got no else: for default block')
2143	return
2144
2145	# Narrow the type
2146	assert not isinstance(default_block, int), default_block
2147
2148	self.write_ind('default: ')
2149	self.accept(default_block)
2150	# don't write 'break'
2151
2152	def _WriteSwitch(self, expr: CallExpr, o: 'mypy.nodes.WithStmt') -> None:
2153	"""Write a switch statement over integers."""
2154	assert len(expr.args) == 1, expr.args
2155
2156	self.write_ind('switch (')
2157	self.accept(expr.args[0])
2158	self.write(') {\n')
2159
2160	assert len(o.body.body) == 1, o.body.body
2161	if_node = o.body.body[0]
2162	assert isinstance(if_node, IfStmt), if_node
2163
2164	self.indent += 1
2165	cases: util.CaseList = []
2166	default_block = util.CollectSwitchCases(self.module_path,
2167	if_node,
2168	cases,
2169	errors=self.errors_keep_going)
2170	self._WriteCases(expr, cases, default_block)
2171
2172	self.indent -= 1
2173	self.write_ind('}\n')
2174
2175	def _WriteTagSwitch(self, expr: CallExpr,
2176	o: 'mypy.nodes.WithStmt') -> None:
2177	"""Write a switch statement over ASDL types."""
2178	assert len(expr.args) == 1, expr.args
2179
2180	self.write_ind('switch (')
2181	self.accept(expr.args[0])
2182	self.write('->tag()) {\n')
2183
2184	assert len(o.body.body) == 1, o.body.body
2185	if_node = o.body.body[0]
2186	assert isinstance(if_node, IfStmt), if_node
2187
2188	self.indent += 1
2189	cases: util.CaseList = []
2190	default_block = util.CollectSwitchCases(self.module_path,
2191	if_node,
2192	cases,
2193	errors=self.errors_keep_going)
2194	self._WriteCases(expr, cases, default_block)
2195
2196	self.indent -= 1
2197	self.write_ind('}\n')
2198
2199	def _StrSwitchCases(self, cases: util.CaseList) -> Any:
2200	cases2: List[Tuple[int, str, 'mypy.nodes.Block']] = []
2201	for expr, body in cases:
2202	if not isinstance(expr, CallExpr):
2203	# non-fatal check from CollectSwitchCases
2204	break
2205
2206	args = expr.args
2207	if len(args) != 1:
2208	self.report_error(
2209	expr,
2210	'str_switch can only have case("x"), not case("x", "y"): got %r'
2211	% args)
2212	break
2213
2214	if not isinstance(args[0], StrExpr):
2215	self.report_error(
2216	expr,
2217	'str_switch can only be used with constant strings, got %s'
2218	% args[0])
2219	break
2220
2221	s = args[0].value
2222	cases2.append((len(s), s, body))
2223
2224	# Sort by string length
2225	cases2.sort(key=lambda pair: pair[0])
2226	grouped = itertools.groupby(cases2, key=lambda pair: pair[0])
2227	return grouped
2228
2229	def _WriteStrSwitch(self, expr: CallExpr,
2230	o: 'mypy.nodes.WithStmt') -> None:
2231	"""Write a switch statement over strings."""
2232	assert len(expr.args) == 1, expr.args
2233
2234	switch_expr = expr # for later error
2235
2236	switch_var = expr.args[0]
2237	if not isinstance(switch_var, NameExpr):
2238	self.report_error(
2239	expr.args[0],
2240	'str_switch(x) accepts only a variable name, got %s' %
2241	switch_var)
2242	return
2243
2244	self.write_ind('switch (len(%s)) {\n' % switch_var.name)
2245
2246	# There can only be one thing under 'with str_switch'
2247	assert len(o.body.body) == 1, o.body.body
2248	if_node = o.body.body[0]
2249	assert isinstance(if_node, IfStmt), if_node
2250
2251	self.indent += 1
2252
2253	cases: util.CaseList = []
2254	default_block = util.CollectSwitchCases(self.module_path,
2255	if_node,
2256	cases,
2257	errors=self.errors_keep_going)
2258
2259	grouped_cases = self._StrSwitchCases(cases)
2260	# Warning: this consumes internal iterator
2261	#self.log('grouped %s', list(grouped_cases))
2262
2263	for str_len, group in grouped_cases:
2264	self.write_ind('case %s: {\n' % str_len)
2265	if_num = 0
2266	for _, case_str, block in group:
2267	self.indent += 1
2268
2269	else_str = '' if if_num == 0 else 'else '
2270	self.write_ind('%sif (str_equals_c(%s, %s, %d)) ' %
2271	(else_str, switch_var.name,
2272	PythonStringLiteral(case_str), str_len))
2273	self.accept(block)
2274
2275	self.indent -= 1
2276	if_num += 1
2277
2278	self.indent += 1
2279	self.write_ind('else {\n')
2280	self.write_ind(' goto str_switch_default;\n')
2281	self.write_ind('}\n')
2282	self.indent -= 1
2283
2284	self.write_ind('}\n')
2285	self.write_ind(' break;\n')
2286
2287	if default_block == -1:
2288	# an error occurred
2289	return
2290	if default_block == -2:
2291	self.report_error(switch_expr,
2292	'str_switch got no else: for default block')
2293	return
2294
2295	# Narrow the type
2296	assert not isinstance(default_block, int), default_block
2297
2298	self.write('\n')
2299	self.write_ind('str_switch_default:\n')
2300	self.write_ind('default: ')
2301	self.accept(default_block)
2302
2303	self.indent -= 1
2304	self.write_ind('}\n')
2305
2306	def visit_with_stmt(self, o: 'mypy.nodes.WithStmt') -> None:
2307	"""
2308	Translate only blocks of this form:
2309
2310	with switch(x) as case:
2311	if case(0):
2312	print('zero')
2313	elif case(1, 2, 3):
2314	print('low')
2315	else:
2316	print('other')
2317
2318	switch(x) {
2319	case 0:
2320	print('zero')
2321	break;
2322	case 1:
2323	case 2:
2324	case 3:
2325	print('low')
2326	break;
2327	default:
2328	print('other')
2329	break;
2330	}
2331
2332	Or:
2333
2334	with ctx_Bar(bar, x, y):
2335	x()
2336
2337	{
2338	ctx_Bar(bar, x, y)
2339	x();
2340	}
2341	"""
2342	#log('WITH')
2343	#log('expr %s', o.expr)
2344	#log('target %s', o.target)
2345
2346	assert len(o.expr) == 1, o.expr
2347	expr = o.expr[0]
2348	assert isinstance(expr, CallExpr), expr
2349
2350	# There is no 'with mylib.tagswitch(x)', only 'with tagswitch(x)'
2351	# But we have with alloc.ctx_SourceCode
2352	#assert isinstance(expr.callee, NameExpr), expr.callee
2353
2354	callee_name = expr.callee.name
2355	if callee_name == 'switch':
2356	self._WriteSwitch(expr, o)
2357	elif callee_name == 'str_switch':
2358	self._WriteStrSwitch(expr, o)
2359	elif callee_name == 'tagswitch':
2360	self._WriteTagSwitch(expr, o)
2361	else:
2362	assert isinstance(expr, CallExpr), expr
2363	self.write_ind('{ // with\n')
2364	self.indent += 1
2365
2366	self.write_ind('')
2367	self.accept(expr.callee)
2368
2369	# FIX: Use braced initialization to avoid most-vexing parse when
2370	# there are 0 args!
2371	self.write(' ctx{')
2372	for i, arg in enumerate(expr.args):
2373	if i != 0:
2374	self.write(', ')
2375	self.accept(arg)
2376	self.write('};\n\n')
2377
2378	self._WriteBody(o.body.body)
2379
2380	self.indent -= 1
2381	self.write_ind('}\n')
2382
2383	def visit_del_stmt(self, o: 'mypy.nodes.DelStmt') -> None:
2384
2385	d = o.expr
2386	if isinstance(d, IndexExpr):
2387	self.write_ind('')
2388	self.accept(d.base)
2389
2390	if isinstance(d.index, SliceExpr):
2391	# del mylist[:] -> mylist->clear()
2392
2393	sl = d.index
2394	assert sl.begin_index is None, sl
2395	assert sl.end_index is None, sl
2396	self.write('->clear()')
2397	else:
2398	# del mydict[mykey] raises KeyError, which we don't want
2399	raise AssertionError(
2400	'Use mylib.dict_erase(d, key) instead of del d[key]')
2401
2402	self.write(';\n')
2403
2404	def oils_visit_constructor(self, o: ClassDef, stmt: FuncDef,
2405	base_class_sym: util.SymbolPath) -> None:
2406	self.write('\n')
2407	self.write('%s::%s(', o.name, o.name)
2408	self._WriteFuncParams(stmt, write_defaults=False)
2409	self.write(')')
2410
2411	first_index = 0
2412
2413	# Skip docstring
2414	maybe_skip_stmt = stmt.body.body[0]
2415	if (isinstance(maybe_skip_stmt, ExpressionStmt) and
2416	isinstance(maybe_skip_stmt.expr, StrExpr)):
2417	first_index += 1
2418
2419	# Check for Base.__init__(self, ...) and move that to the initializer list.
2420	first_stmt = stmt.body.body[first_index]
2421	if (isinstance(first_stmt, ExpressionStmt) and
2422	isinstance(first_stmt.expr, CallExpr)):
2423	expr = first_stmt.expr
2424	#log('expr %s', expr)
2425	callee = first_stmt.expr.callee
2426
2427	# TextOutput() : ColorOutput(f), ... {
2428	if (isinstance(callee, MemberExpr) and callee.name == '__init__'):
2429	base_constructor_args = expr.args
2430	#log('ARGS %s', base_constructor_args)
2431	self.write(' : %s(',
2432	SymbolToString(base_class_sym, strip_package=True))
2433	for i, arg in enumerate(base_constructor_args):
2434	if i == 0:
2435	continue # Skip 'this'
2436	if i != 1:
2437	self.write(', ')
2438	self.accept(arg)
2439	self.write(')')
2440
2441	first_index += 1
2442
2443	self.write(' {\n')
2444
2445	# Now visit the rest of the statements
2446	self.indent += 1
2447
2448	if _IsContextManager(self.current_class_name):
2449	# For ctx_* classes only, do gHeap.PushRoot() for all the pointer
2450	# members
2451	member_vars = self.all_member_vars[o]
2452	for name in sorted(member_vars):
2453	_, c_type, is_managed = member_vars[name]
2454	if is_managed:
2455	# VALIDATE_ROOTS doesn't complain even if it's not
2456	# initialized? Should be initialized after PushRoot().
2457	#self.write_ind('this->%s = nullptr;\n' % name)
2458	self.write_ind(
2459	'gHeap.PushRoot(reinterpret_cast<RawObject**>(&(this->%s)));\n'
2460	% name)
2461
2462	for node in stmt.body.body[first_index:]:
2463	self.accept(node)
2464	self.indent -= 1
2465	self.write('}\n')
2466
2467	def oils_visit_dunder_exit(self, o: ClassDef, stmt: FuncDef,
2468	base_class_sym: util.SymbolPath) -> None:
2469	self.write('\n')
2470	self.write_ind('%s::~%s()', o.name, o.name)
2471
2472	self.write(' {\n')
2473	self.indent += 1
2474
2475	# TODO:
2476	# - Can't throw exception in destructor.
2477	# - Check that you don't return early from destructor. If so, we skip
2478	# PopRoot(), which messes up the invariant!
2479
2480	for node in stmt.body.body:
2481	self.accept(node)
2482
2483	# For ctx_* classes only , gHeap.PopRoot() for all the pointer members
2484	if _IsContextManager(self.current_class_name):
2485	member_vars = self.all_member_vars[o]
2486	for name in sorted(member_vars):
2487	_, c_type, is_managed = member_vars[name]
2488	if is_managed:
2489	self.write_ind('gHeap.PopRoot();\n')
2490	else:
2491	self.report_error(
2492	o, 'Any class with __exit__ should be named ctx_Foo (%s)' %
2493	(self.current_class_name, ))
2494	return
2495
2496	self.indent -= 1
2497	self.write('}\n')
2498
2499	def oils_visit_method(self, o: ClassDef, stmt: FuncDef,
2500	base_class_sym: util.SymbolPath) -> None:
2501	self.accept(stmt)
2502
2503	# Module structure
2504
2505	def visit_import(self, o: 'mypy.nodes.Import') -> None:
2506	pass
2507
2508	def visit_import_from(self, o: 'mypy.nodes.ImportFrom') -> None:
2509	"""
2510	Write C++ namespace aliases and 'using' for imports.
2511	We need them in the 'decl' phase for default arguments like
2512	runtime_asdl::scope_e -> scope_e
2513	"""
2514	if o.id in ('__future__', 'typing'):
2515	return # do nothing
2516
2517	for name, alias in o.names:
2518	#self.log('ImportFrom id: %s name: %s alias: %s', o.id, name, alias)
2519
2520	if name == 'log': # varargs translation
2521	continue
2522
2523	if o.id == 'mycpp.mylib':
2524	# These mylib functions are translated in a special way
2525	if name in ('switch', 'tagswitch', 'str_switch', 'iteritems',
2526	'NewDict', 'probe'):
2527	continue
2528	# STDIN_FILENO is #included
2529	if name == 'STDIN_FILENO':
2530	continue
2531
2532	# A heuristic that works for the Oils import style.
2533	if '.' in o.id:
2534	# from mycpp.mylib import log => using mylib::log
2535	translate_import = True
2536	else:
2537	# from core import util => NOT translated
2538	# We just rely on 'util' being defined.
2539	translate_import = False
2540
2541	if translate_import:
2542	dotted_parts = o.id.split('.')
2543	last_dotted = dotted_parts[-1]
2544
2545	# Omit these:
2546	# from _gen.ysh import grammar_nt
2547	if last_dotted == 'ysh':
2548	return
2549	# from _devbuild.gen import syntax_asdl
2550	if last_dotted == 'gen':
2551	return
2552
2553	# Problem:
2554	# - The decl stage has to return yaks_asdl::mod_def, so imports should go there
2555	# - But if you change this to decl_write() instead of
2556	# write(), you end up 'using error::e_usage' in say
2557	# 'assign_osh', and it hasn't been defined yet.
2558
2559	if alias:
2560	# using runtime_asdl::emit_e = EMIT;
2561	self.write_ind('using %s = %s::%s;\n', alias, last_dotted,
2562	name)
2563	else:
2564	# from _devbuild.gen.id_kind_asdl import Id
2565	# -> using id_kind_asdl::Id.
2566	using_str = 'using %s::%s;\n' % (last_dotted, name)
2567	self.write_ind(using_str)
2568
2569	# Fully qualified:
2570	# self.write_ind('using %s::%s;\n', '::'.join(dotted_parts), name)
2571
2572	else:
2573	# If we're importing a module without an alias, we don't need to do
2574	# anything. 'namespace cmd_eval' is already defined.
2575	if not alias:
2576	return
2577
2578	# from asdl import format as fmt
2579	# -> namespace fmt = format;
2580	self.write_ind('namespace %s = %s;\n', alias, name)
2581
2582	# Statements
2583
2584	def _WriteLocals(self, local_var_list: List[LocalVar]) -> None:
2585	# TODO: put the pointers first, and then register a single
2586	# StackRoots record.
2587	done = set()
2588	for lval_name, lval_type, is_param in local_var_list:
2589	c_type = GetCType(lval_type)
2590	if not is_param and lval_name not in done:
2591	if util.SMALL_STR and c_type == 'Str':
2592	self.write_ind('%s %s(nullptr);\n', c_type, lval_name)
2593	else:
2594	rhs = ' = nullptr' if CTypeIsManaged(c_type) else ''
2595	self.write_ind('%s %s%s;\n', c_type, lval_name, rhs)
2596
2597	# TODO: we're not skipping the assignment, because of
2598	# the RHS
2599	if util.IsUnusedVar(lval_name):
2600	# suppress C++ unused var compiler warnings!
2601	self.write_ind('(void)%s;\n' % lval_name)
2602
2603	done.add(lval_name)
2604
2605	# Figure out if we have any roots to write with StackRoots
2606	roots = [] # keep it sorted
2607	full_func_name = None
2608	if self.current_func_node:
2609	full_func_name = SplitPyName(self.current_func_node.fullname)
2610
2611	for lval_name, lval_type, is_param in local_var_list:
2612	c_type = GetCType(lval_type)
2613	#self.log('%s %s %s', lval_name, c_type, is_param)
2614	if lval_name not in roots and CTypeIsManaged(c_type):
2615	if (not self.stack_roots or self.stack_roots.needs_root(
2616	full_func_name, SplitPyName(lval_name))):
2617	roots.append(lval_name)
2618
2619	#self.log('roots %s', roots)
2620
2621	if len(roots):
2622	if (self.stack_roots_warn and len(roots) > self.stack_roots_warn):
2623	log('WARNING: %s() has %d stack roots. Consider refactoring this function.'
2624	% (self.current_func_node.fullname, len(roots)))
2625
2626	for i, r in enumerate(roots):
2627	self.write_ind('StackRoot _root%d(&%s);\n' % (i, r))
2628
2629	self.write('\n')
2630
2631	def visit_block(self, block: 'mypy.nodes.Block') -> None:
2632	self.write('{\n') # not indented to use same line as while/if
2633
2634	self.indent += 1
2635	self._WriteBody(block.body)
2636	self.indent -= 1
2637
2638	self.write_ind('}\n')
2639
2640	def oils_visit_expression_stmt(self,
2641	o: 'mypy.nodes.ExpressionStmt') -> None:
2642	self.write_ind('')
2643	self.accept(o.expr)
2644	self.write(';\n')
2645
2646	def visit_operator_assignment_stmt(
2647	self, o: 'mypy.nodes.OperatorAssignmentStmt') -> None:
2648	self.write_ind('')
2649	self.accept(o.lvalue)
2650	self.write(' %s= ', o.op) # + to +=
2651	self.accept(o.rvalue)
2652	self.write(';\n')
2653
2654	def visit_while_stmt(self, o: 'mypy.nodes.WhileStmt') -> None:
2655	self.write_ind('while (')
2656	self.accept(o.expr)
2657	self.write(') ')
2658	self.accept(o.body)
2659
2660	def visit_return_stmt(self, o: 'mypy.nodes.ReturnStmt') -> None:
2661	# Examples:
2662	# return
2663	# return None
2664	# return my_int + 3;
2665	self.write_ind('return ')
2666	if o.expr:
2667	if not (isinstance(o.expr, NameExpr) and o.expr.name == 'None'):
2668
2669	# Note: the type of the return expression (self.types[o.expr])
2670	# and the return type of the FUNCTION are different. Use the
2671	# latter.
2672	ret_type = self.current_func_node.type.ret_type
2673
2674	c_ret_type, returning_tuple, _ = GetCReturnType(ret_type)
2675
2676	# return '', None # tuple literal
2677	# but NOT
2678	# return tuple_func()
2679	if returning_tuple and isinstance(o.expr, TupleExpr):
2680	self.write('%s(' % c_ret_type)
2681	for i, item in enumerate(o.expr.items):
2682	if i != 0:
2683	self.write(', ')
2684	self.accept(item)
2685	self.write(');\n')
2686	return
2687
2688	# Not returning tuple
2689	self.accept(o.expr)
2690
2691	self.write(';\n')
2692
2693	def visit_if_stmt(self, o: 'mypy.nodes.IfStmt') -> None:
2694	# Not sure why this wouldn't be true
2695	assert len(o.expr) == 1, o.expr
2696
2697	condition = o.expr[0]
2698
2699	if not _CheckCondition(condition, self.types):
2700	self.report_error(
2701	o,
2702	"Use explicit len(obj) or 'obj is not None' for mystr, mylist, mydict"
2703	)
2704	return
2705
2706	if util.ShouldVisitIfExpr(o):
2707	self.write_ind('if (')
2708	for e in o.expr:
2709	self.accept(e)
2710	self.write(') ')
2711
2712	if util.ShouldVisitIfBody(o):
2713	cond = util.GetSpecialIfCondition(o)
2714	if cond == 'CPP':
2715	self.write_ind('// if MYCPP\n')
2716	self.write_ind('')
2717
2718	for body in o.body:
2719	self.accept(body)
2720
2721	if cond == 'CPP':
2722	self.write_ind('// endif MYCPP\n')
2723
2724	if util.ShouldVisitElseBody(o):
2725	cond = util.GetSpecialIfCondition(o)
2726	if cond == 'PYTHON':
2727	self.write_ind('// if not PYTHON\n')
2728	self.write_ind('')
2729
2730	if util.ShouldVisitIfBody(o):
2731	self.write_ind('else ')
2732
2733	self.accept(o.else_body)
2734
2735	if cond == 'PYTHON':
2736	self.write_ind('// endif MYCPP\n')
2737
2738	def visit_break_stmt(self, o: 'mypy.nodes.BreakStmt') -> None:
2739	self.write_ind('break;\n')
2740
2741	def visit_continue_stmt(self, o: 'mypy.nodes.ContinueStmt') -> None:
2742	self.write_ind('continue;\n')
2743
2744	def visit_pass_stmt(self, o: 'mypy.nodes.PassStmt') -> None:
2745	self.write_ind('; // pass\n')
2746
2747	def visit_raise_stmt(self, o: 'mypy.nodes.RaiseStmt') -> None:
2748	to_raise = o.expr
2749
2750	if to_raise:
2751	if isinstance(to_raise, CallExpr) and isinstance(
2752	to_raise.callee, NameExpr):
2753	callee_name = to_raise.callee.name
2754	if callee_name == 'AssertionError':
2755	# C++ compiler is aware of assert(0) for unreachable code
2756	self.write_ind('assert(0); // AssertionError\n')
2757	return
2758	if callee_name == 'NotImplementedError':
2759	self.write_ind(
2760	'FAIL(kNotImplemented); // Python NotImplementedError\n'
2761	)
2762	return
2763	self.write_ind('throw ')
2764	self.accept(to_raise)
2765	self.write(';\n')
2766	else:
2767	# raise without arg
2768	self.write_ind('throw;\n')
2769
2770	def visit_try_stmt(self, o: 'mypy.nodes.TryStmt') -> None:
2771	self.write_ind('try ')
2772	self.accept(o.body)
2773	caught = False
2774
2775	for t, v, handler in zip(o.types, o.vars, o.handlers):
2776	c_type = None
2777
2778	if isinstance(t, NameExpr):
2779	if t.name in ('IOError', 'OSError'):
2780	self.report_error(
2781	handler,
2782	'Use except (IOError, OSError) rather than catching just one'
2783	)
2784	c_type = '%s*' % t.name
2785
2786	elif isinstance(t, MemberExpr):
2787	# We never use 'except foo.bar.T', only `foo.T'
2788	assert isinstance(t.expr, NameExpr), t.expr
2789	c_type = '%s::%s*' % (t.expr.name, t.name)
2790
2791	elif isinstance(t, TupleExpr):
2792	if len(t.items) == 2:
2793	e1 = t.items[0]
2794	e2 = t.items[1]
2795	if isinstance(e1, NameExpr) and isinstance(e2, NameExpr):
2796	names = [e1.name, e2.name]
2797	names.sort()
2798	if names == ['IOError', 'OSError']:
2799	c_type = 'IOError_OSError*' # Base class in mylib
2800
2801	else:
2802	raise AssertionError()
2803
2804	if c_type is None:
2805	self.report_error(o, "try couldn't determine c_type")
2806	return
2807
2808	if v:
2809	self.write_ind('catch (%s %s) ', c_type, v.name)
2810	else:
2811	self.write_ind('catch (%s) ', c_type)
2812	self.accept(handler)
2813
2814	caught = True
2815
2816	if not caught:
2817	self.report_error(o, 'try should have an except')
2818
2819	if o.else_body:
2820	self.report_error(o, 'try/else not supported')
2821
2822	if o.finally_body:
2823	self.report_error(o, 'try/finally not supported')