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			250 lines
		
	
	
	
		
			7.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			250 lines
		
	
	
	
		
			7.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| """Interface to the compiler's internal symbol tables"""
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| from __future__ import nested_scopes
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| 
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| import _symtable
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| from _symtable import USE, DEF_GLOBAL, DEF_LOCAL, DEF_PARAM, \
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|      DEF_STAR, DEF_DOUBLESTAR, DEF_INTUPLE, DEF_FREE, \
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|      DEF_FREE_GLOBAL, DEF_FREE_CLASS, DEF_IMPORT, DEF_BOUND
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| 
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| import weakref
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| 
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| __all__ = ["symtable", "SymbolTable", "newSymbolTable", "Class",
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|            "Function", "Symbol"]
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| 
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| def symtable(code, filename, compile_type):
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|     raw = _symtable.symtable(code, filename, compile_type)
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|     return newSymbolTable(raw[0], filename)
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| 
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| class SymbolTableFactory:
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|     def __init__(self):
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|         self.__memo = weakref.WeakValueDictionary()
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| 
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|     def new(self, table, filename):
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|         if table.type == _symtable.TYPE_FUNCTION:
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|             return Function(table, filename)
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|         if table.type == _symtable.TYPE_CLASS:
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|             return Class(table, filename)
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|         return SymbolTable(table, filename)
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| 
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|     def __call__(self, table, filename):
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|         key = table, filename
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|         obj = self.__memo.get(key, None)
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|         if obj is None:
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|             obj = self.__memo[key] = self.new(table, filename)
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|         return obj
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| 
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| newSymbolTable = SymbolTableFactory()
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|     
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| def bool(x):
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|     """Helper to force boolean result to 1 or 0"""
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|     if x:
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|         return 1
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|     return 0
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| 
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| def is_free(flags):
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|     if (flags & (USE | DEF_FREE)) \
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|        and (flags & (DEF_LOCAL | DEF_PARAM | DEF_GLOBAL)):
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|         return 1
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|     if flags & DEF_FREE_CLASS:
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|         return 1
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|     return 0
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| 
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| class SymbolTable:
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|     def __init__(self, raw_table, filename):
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|         self._table = raw_table
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|         self._filename = filename
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|         self._symbols = {}
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| 
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|     def __repr__(self):
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|         if self.__class__ == SymbolTable:
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|             kind = ""
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|         else:
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|             kind = "%s " % self.__class__.__name__
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|         
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|         if self._table.name == "global":
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|             return "<%sSymbolTable for module %s>" % (kind, self._filename)
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|         else:
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|             return "<%sSymbolTable for %s in %s>" % (kind, self._table.name,
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|                                                      self._filename)
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| 
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|     def get_type(self):
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|         if self._table.type == _symtable.TYPE_MODULE:
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|             return "module"
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|         if self._table.type == _symtable.TYPE_FUNCTION:
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|             return "function"
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|         if self._table.type == _symtable.TYPE_CLASS:
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|             return "class"
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|         assert self._table.type in (1, 2, 3), \
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|                "unexpected type: %s" % self._table.type
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| 
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|     def get_id(self):
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|         return self._table.id
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| 
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|     def get_name(self):
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|         return self._table.name
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| 
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|     def get_lineno(self):
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|         return self._table.lineno
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| 
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|     def is_optimized(self):
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|         return bool(self._table.type == _symtable.TYPE_FUNCTION
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|                     and not self._table.optimized)
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| 
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|     def is_nested(self):
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|         return bool(self._table.nested)
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| 
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|     def has_children(self):
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|         return bool(self._table.children)
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| 
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|     def has_exec(self):
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|         return bool()
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| 
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|     def get_identifiers(self):
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|         return self._table.symbols.keys()
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| 
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|     def lookup(self, name):
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|         sym = self._symbols.get(name)
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|         if sym is None:
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|             flags = self._table.symbols[name]
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|             namespaces = self.__check_children(name)
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|             sym = self._symbols[name] = Symbol(name, flags, namespaces)
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|         return sym
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| 
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|     def get_symbols(self):
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|         return [self.lookup(ident) for ident in self.get_identifiers()]
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| 
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|     def __check_children(self, name):
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|         return [newSymbolTable(st, self._filename)
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|                 for st in self._table.children
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|                 if st.name == name]
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| 
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|     def get_children(self):
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|         return [newSymbolTable(st, self._filename)
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|                 for st in self._table.children]
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| 
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| class Function(SymbolTable):
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| 
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|     # Default values for instance variables
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|     __params = None
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|     __locals = None
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|     __frees = None
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|     __globals = None
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| 
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|     def __idents_matching(self, test_func):
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|         return tuple([ident for ident in self.get_identifiers()
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|                       if test_func(self._table.symbols[ident])])
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| 
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|     def get_parameters(self):
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|         if self.__params is None:
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|             self.__params = self.__idents_matching(lambda x:x & DEF_PARAM)
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|         return self.__params
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| 
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|     def get_locals(self):
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|         if self.__locals is None:
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|             self.__locals = self.__idents_matching(lambda x:x & DEF_BOUND)
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|         return self.__locals
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|         
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|     def get_globals(self):
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|         if self.__globals is None:
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|             glob = DEF_GLOBAL | DEF_FREE_GLOBAL
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|             self.__globals = self.__idents_matching(lambda x:x & glob)
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|         return self.__globals
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| 
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|     def get_frees(self):
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|         if self.__frees is None:
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|             self.__frees = self.__idents_matching(is_free)
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|         return self.__frees
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| 
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| class Class(SymbolTable):
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| 
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|     __methods = None
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| 
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|     def get_methods(self):
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|         if self.__methods is None:
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|             d = {}
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|             for st in self._table.children:
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|                 d[st.name] = 1
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|             self.__methods = tuple(d.keys())
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|         return self.__methods
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| 
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| class Symbol:
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|     def __init__(self, name, flags, namespaces=None):
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|         self.__name = name
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|         self.__flags = flags
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|         self.__namespaces = namespaces or ()
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| 
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|     def __repr__(self):
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|         return "<symbol '%s'>" % self.__name
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| 
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|     def get_name(self):
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|         return self.__name
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| 
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|     def is_referenced(self):
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|         return bool(self.__flags & _symtable.USE)
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| 
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|     def is_parameter(self):
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|         return bool(self.__flags & DEF_PARAM)
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| 
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|     def is_global(self):
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|         return bool((self.__flags & DEF_GLOBAL) 
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|                     or (self.__flags & DEF_FREE_GLOBAL))
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| 
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|     def is_vararg(self):
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|         return bool(self.flag & DEF_STAR)
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| 
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|     def is_keywordarg(self):
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|         return bool(self.__flags & DEF_STARSTAR)
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| 
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|     def is_local(self):
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|         return bool(self.__flags & DEF_BOUND)
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| 
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|     def is_free(self):
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|         if (self.__flags & (USE | DEF_FREE)) \
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|             and (self.__flags & (DEF_LOCAL | DEF_PARAM | DEF_GLOBAL)):
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|             return 1
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|         if self.__flags & DEF_FREE_CLASS:
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|             return 1
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|         return 0
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| 
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|     def is_imported(self):
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|         return bool(self.__flags & DEF_IMPORT)
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| 
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|     def is_assigned(self):
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|         return bool(self.__flags & DEF_LOCAL)
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| 
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|     def is_in_tuple(self):
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|         return bool(self.__flags & DEF_INTUPLE)
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| 
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|     def is_namespace(self):
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|         """Returns true if name binding introduces new namespace.
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| 
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|         If the name is used as the target of a function or class
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|         statement, this will be true.
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| 
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|         Note that a single name can be bound to multiple objects.  If
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|         is_namespace() is true, the name may also be bound to other
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|         objects, like an int or list, that does not introduce a new
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|         namespace.
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|         """
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|         return bool(self.__namespaces)
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| 
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|     def get_namespaces(self):
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|         """Return a list of namespaces bound to this name"""
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|         return self.__namespaces
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| 
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|     def get_namespace(self):
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|         """Returns the single namespace bound to this name.
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| 
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|         Raises ValueError if the name is bound to multiple namespaces.
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|         """
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|         if len(self.__namespaces) != 1:
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|             raise ValueError, "name is bound to multiple namespaces"
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|         return self.__namespaces[0]
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| 
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| if __name__ == "__main__":
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|     import os, sys
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|     src = open(sys.argv[0]).read()
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|     mod = symtable(src, os.path.split(sys.argv[0])[1], "exec")
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|     for ident in mod.get_identifiers():
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|         info = mod.lookup(ident)
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|         print info, info.is_local(), info.is_namespace()
 | 
