source: titan/mediathek/localhoster/lib/python2.7/symtable.py @ 40523

Last change on this file since 40523 was 40094, checked in by obi, 7 years ago

tithek add yoztube-dl support

File size: 7.3 KB
Line 
1"""Interface to the compiler's internal symbol tables"""
2
3import _symtable
4from _symtable import (USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM,
5     DEF_IMPORT, DEF_BOUND, OPT_IMPORT_STAR, OPT_EXEC, OPT_BARE_EXEC,
6     SCOPE_OFF, SCOPE_MASK, FREE, GLOBAL_IMPLICIT, GLOBAL_EXPLICIT, CELL, LOCAL)
7
8import weakref
9
10__all__ = ["symtable", "SymbolTable", "Class", "Function", "Symbol"]
11
12def symtable(code, filename, compile_type):
13    top = _symtable.symtable(code, filename, compile_type)
14    return _newSymbolTable(top, filename)
15
16class SymbolTableFactory:
17    def __init__(self):
18        self.__memo = weakref.WeakValueDictionary()
19
20    def new(self, table, filename):
21        if table.type == _symtable.TYPE_FUNCTION:
22            return Function(table, filename)
23        if table.type == _symtable.TYPE_CLASS:
24            return Class(table, filename)
25        return SymbolTable(table, filename)
26
27    def __call__(self, table, filename):
28        key = table, filename
29        obj = self.__memo.get(key, None)
30        if obj is None:
31            obj = self.__memo[key] = self.new(table, filename)
32        return obj
33
34_newSymbolTable = SymbolTableFactory()
35
36
37class SymbolTable(object):
38
39    def __init__(self, raw_table, filename):
40        self._table = raw_table
41        self._filename = filename
42        self._symbols = {}
43
44    def __repr__(self):
45        if self.__class__ == SymbolTable:
46            kind = ""
47        else:
48            kind = "%s " % self.__class__.__name__
49
50        if self._table.name == "global":
51            return "<{0}SymbolTable for module {1}>".format(kind, self._filename)
52        else:
53            return "<{0}SymbolTable for {1} in {2}>".format(kind,
54                                                            self._table.name,
55                                                            self._filename)
56
57    def get_type(self):
58        if self._table.type == _symtable.TYPE_MODULE:
59            return "module"
60        if self._table.type == _symtable.TYPE_FUNCTION:
61            return "function"
62        if self._table.type == _symtable.TYPE_CLASS:
63            return "class"
64        assert self._table.type in (1, 2, 3), \
65               "unexpected type: {0}".format(self._table.type)
66
67    def get_id(self):
68        return self._table.id
69
70    def get_name(self):
71        return self._table.name
72
73    def get_lineno(self):
74        return self._table.lineno
75
76    def is_optimized(self):
77        return bool(self._table.type == _symtable.TYPE_FUNCTION
78                    and not self._table.optimized)
79
80    def is_nested(self):
81        return bool(self._table.nested)
82
83    def has_children(self):
84        return bool(self._table.children)
85
86    def has_exec(self):
87        """Return true if the scope uses exec"""
88        return bool(self._table.optimized & (OPT_EXEC | OPT_BARE_EXEC))
89
90    def has_import_star(self):
91        """Return true if the scope uses import *"""
92        return bool(self._table.optimized & OPT_IMPORT_STAR)
93
94    def get_identifiers(self):
95        return self._table.symbols.keys()
96
97    def lookup(self, name):
98        sym = self._symbols.get(name)
99        if sym is None:
100            flags = self._table.symbols[name]
101            namespaces = self.__check_children(name)
102            sym = self._symbols[name] = Symbol(name, flags, namespaces)
103        return sym
104
105    def get_symbols(self):
106        return [self.lookup(ident) for ident in self.get_identifiers()]
107
108    def __check_children(self, name):
109        return [_newSymbolTable(st, self._filename)
110                for st in self._table.children
111                if st.name == name]
112
113    def get_children(self):
114        return [_newSymbolTable(st, self._filename)
115                for st in self._table.children]
116
117
118class Function(SymbolTable):
119
120    # Default values for instance variables
121    __params = None
122    __locals = None
123    __frees = None
124    __globals = None
125
126    def __idents_matching(self, test_func):
127        return tuple([ident for ident in self.get_identifiers()
128                      if test_func(self._table.symbols[ident])])
129
130    def get_parameters(self):
131        if self.__params is None:
132            self.__params = self.__idents_matching(lambda x:x & DEF_PARAM)
133        return self.__params
134
135    def get_locals(self):
136        if self.__locals is None:
137            locs = (LOCAL, CELL)
138            test = lambda x: ((x >> SCOPE_OFF) & SCOPE_MASK) in locs
139            self.__locals = self.__idents_matching(test)
140        return self.__locals
141
142    def get_globals(self):
143        if self.__globals is None:
144            glob = (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT)
145            test = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) in glob
146            self.__globals = self.__idents_matching(test)
147        return self.__globals
148
149    def get_frees(self):
150        if self.__frees is None:
151            is_free = lambda x:((x >> SCOPE_OFF) & SCOPE_MASK) == FREE
152            self.__frees = self.__idents_matching(is_free)
153        return self.__frees
154
155
156class Class(SymbolTable):
157
158    __methods = None
159
160    def get_methods(self):
161        if self.__methods is None:
162            d = {}
163            for st in self._table.children:
164                d[st.name] = 1
165            self.__methods = tuple(d)
166        return self.__methods
167
168
169class Symbol(object):
170
171    def __init__(self, name, flags, namespaces=None):
172        self.__name = name
173        self.__flags = flags
174        self.__scope = (flags >> SCOPE_OFF) & SCOPE_MASK # like PyST_GetScope()
175        self.__namespaces = namespaces or ()
176
177    def __repr__(self):
178        return "<symbol {0!r}>".format(self.__name)
179
180    def get_name(self):
181        return self.__name
182
183    def is_referenced(self):
184        return bool(self.__flags & _symtable.USE)
185
186    def is_parameter(self):
187        return bool(self.__flags & DEF_PARAM)
188
189    def is_global(self):
190        return bool(self.__scope in (GLOBAL_IMPLICIT, GLOBAL_EXPLICIT))
191
192    def is_declared_global(self):
193        return bool(self.__scope == GLOBAL_EXPLICIT)
194
195    def is_local(self):
196        return bool(self.__flags & DEF_BOUND)
197
198    def is_free(self):
199        return bool(self.__scope == FREE)
200
201    def is_imported(self):
202        return bool(self.__flags & DEF_IMPORT)
203
204    def is_assigned(self):
205        return bool(self.__flags & DEF_LOCAL)
206
207    def is_namespace(self):
208        """Returns true if name binding introduces new namespace.
209
210        If the name is used as the target of a function or class
211        statement, this will be true.
212
213        Note that a single name can be bound to multiple objects.  If
214        is_namespace() is true, the name may also be bound to other
215        objects, like an int or list, that does not introduce a new
216        namespace.
217        """
218        return bool(self.__namespaces)
219
220    def get_namespaces(self):
221        """Return a list of namespaces bound to this name"""
222        return self.__namespaces
223
224    def get_namespace(self):
225        """Returns the single namespace bound to this name.
226
227        Raises ValueError if the name is bound to multiple namespaces.
228        """
229        if len(self.__namespaces) != 1:
230            raise ValueError, "name is bound to multiple namespaces"
231        return self.__namespaces[0]
232
233if __name__ == "__main__":
234    import os, sys
235    src = open(sys.argv[0]).read()
236    mod = symtable(src, os.path.split(sys.argv[0])[1], "exec")
237    for ident in mod.get_identifiers():
238        info = mod.lookup(ident)
239        print info, info.is_local(), info.is_namespace()
Note: See TracBrowser for help on using the repository browser.