/usr/lib/python3.6/symtable.py is in libpython3.6-stdlib 3.6.5-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 | """Interface to the compiler's internal symbol tables"""
import _symtable
from _symtable import (USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM,
DEF_IMPORT, DEF_BOUND, DEF_ANNOT, 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_annotated(self):
return bool(self.__flags & DEF_ANNOT)
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())
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