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
|
"""Interface to the compiler's internal symbol tables"""
import _symtable
from _symtable import (USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM,
DEF_IMPORT, DEF_BOUND, SCOPE_OFF, SCOPE_MASK, FREE,
LOCAL, GLOBAL_IMPLICIT, GLOBAL_EXPLICIT, CELL)
import weakref
__all__ = ["symtable", "SymbolTable", "Class", "Function", "Symbol"]
def symtable(code, filename, compile_type):
top = _symtable.symtable(code, filename, compile_type)
return _newSymbolTable(top, filename)
class SymbolTableFactory:
def __init__(self):
self.__memo = weakref.WeakValueDictionary()
def new(self, table, filename):
if table.type == _symtable.TYPE_FUNCTION:
return Function(table, filename)
if table.type == _symtable.TYPE_CLASS:
return Class(table, filename)
return SymbolTable(table, filename)
def __call__(self, table, filename):
key = table, filename
obj = self.__memo.get(key, None)
if obj is None:
obj = self.__memo[key] = self.new(table, filename)
return obj
_newSymbolTable = SymbolTableFactory()
class SymbolTable(object):
def __init__(self, raw_table, filename):
self._table = raw_table
self._filename = filename
self._symbols = {}
def __repr__(self):
if self.__class__ == SymbolTable:
kind = ""
else:
kind = "%s " % self.__class__.__name__
if self._table.name == "global":
return "<{0}SymbolTable for module {1}>".format(kind, self._filename)
else:
return "<{0}SymbolTable for {1} in {2}>".format(kind,
self._table.name,
self._filename)
def get_type(self):
if self._table.type == _symtable.TYPE_MODULE:
return "module"
if self._table.type == _symtable.TYPE_FUNCTION:
return "function"
if self._table.type == _symtable.TYPE_CLASS:
return "class"
assert self._table.type in (1, 2, 3), \
"unexpected type: {0}".format(self._table.type)
def get_id(self):
return self._table.id
def get_name(self):
return self._table.name
def get_lineno(self):
return self._table.lineno
def is_optimized(self):
return bool(self._table.type == _symtable.TYPE_FUNCTION)
def is_nested(self):
return bool(self._table.nested)
def has_children(self):
return bool(self._table.children)
def has_exec(self):
"""Return true if the scope uses exec. Deprecated method."""
return False
def get_identifiers(self):
return self._table.symbols.keys()
def lookup(self, name):
sym = self._symbols.get(name)
if sym is None:
flags = self._table.symbols[name]
namespaces = self.__check_children(name)
sym = self._symbols[name] = Symbol(name, flags, namespaces)
return sym
def get_symbols(self):
return [self.lookup(ident) for ident in self.get_identifiers()]
def __check_children(self, name):
return [_newSymbolTable(st, self._filename)
for st in self._table.children
if st.name == name]
def get_children(self):
return [_newSymbolTable(st, self._filename)
for st in self._table.children]
class Function(SymbolTable):
# Default values for instance variables
__params = None
__locals = None
__frees = None
__globals = None
def __idents_matching(self, test_func):
return tuple([ident for ident in self.get_identifiers()
if test_func(self._table.symbols[ident])])
def get_parameters(self):
if self.__params is None:
self.__params = self.__idents_matching(lambda x:x & DEF_PARAM)
return self.__params
def get_locals(self):
if self.__locals is None:
locs = (LOCAL, CELL)
test = lambda x: ((x >> SCOPE_OFF) & SCOPE_MASK) in locs
self.__locals = self.__idents_matching(test)
return self.__locals
def get_globals(self):
if self.__globals is None:
glob = (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT)
test = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) in glob
self.__globals = self.__idents_matching(test)
return self.__globals
def get_frees(self):
if self.__frees is None:
is_free = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) == FREE
self.__frees = self.__idents_matching(is_free)
return self.__frees
class Class(SymbolTable):
__methods = None
def get_methods(self):
if self.__methods is None:
d = {}
for st in self._table.children:
d[st.name] = 1
self.__methods = tuple(d)
return self.__methods
class Symbol(object):
def __init__(self, name, flags, namespaces=None):
self.__name = name
self.__flags = flags
self.__scope = (flags >> SCOPE_OFF) & SCOPE_MASK # like PyST_GetScope()
self.__namespaces = namespaces or ()
def __repr__(self):
return "<symbol {0!r}>".format(self.__name)
def get_name(self):
return self.__name
def is_referenced(self):
return bool(self.__flags & _symtable.USE)
def is_parameter(self):
return bool(self.__flags & DEF_PARAM)
def is_global(self):
return bool(self.__scope in (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT))
def is_declared_global(self):
return bool(self.__scope == GLOBAL_EXPLICIT)
def is_local(self):
return bool(self.__flags & DEF_BOUND)
def is_free(self):
return bool(self.__scope == FREE)
def is_imported(self):
return bool(self.__flags & DEF_IMPORT)
def is_assigned(self):
return bool(self.__flags & DEF_LOCAL)
def is_namespace(self):
"""Returns true if name binding introduces new namespace.
If the name is used as the target of a function or class
statement, this will be true.
Note that a single name can be bound to multiple objects. If
is_namespace() is true, the name may also be bound to other
objects, like an int or list, that does not introduce a new
namespace.
"""
return bool(self.__namespaces)
def get_namespaces(self):
"""Return a list of namespaces bound to this name"""
return self.__namespaces
def get_namespace(self):
"""Returns the single namespace bound to this name.
Raises ValueError if the name is bound to multiple namespaces.
"""
if len(self.__namespaces) != 1:
raise ValueError("name is bound to multiple namespaces")
return self.__namespaces[0]
if __name__ == "__main__":
import os, sys
with open(sys.argv[0]) as f:
src = f.read()
mod = symtable(src, os.path.split(sys.argv[0])[1], "exec")
for ident in mod.get_identifiers():
info = mod.lookup(ident)
print(info, info.is_local(), info.is_namespace())
|
