Source Code for Module advene.util.autoproperty

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 12  # GNU General Public License for more details. 
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 17  # 
 18   
 19  from sys import _getframe 
 20   
 21 -def autoproperty(*args): 
 22      """Decorate a class method to create or update a property of the class. 
 23   
 24      Usage #1::: 
 25          @autoproperty 
 26          def _get_foobar(self): 
 27              # some code 
 28   
 29          @autoproperty 
 30          def set_foobar(self, val, option=0) 
 31              # some code 
 32   
 33      Usage #2::: 
 34          @autoproperty("foo", "get") 
 35          def bar(self): 
 36              # some code 
 37   
 38          @autoproperty 
 39          def baz(self, val): 
 40              # some code 
 41   
 42      In the first usage, the name of the property and the role of the method 
 43      (get, set or del) are inferred from the name of the method. The following 
 44      name patterns are recognized: role_name, _role_name, roleName, _roleName, 
 45      where role can be any combination of case. In the two latter cases, the 
 46      first letter of the name will automatically be downcased. 
 47   
 48      The docstring of the property is set to the docstring of the first method 
 49      used to define the property. 
 50      """ 
 51      L = len(args) 
 52      assert 1 <= L <= 2 
 53      if len(args) == 1: 
 54          func = args[0] 
 55          name, role = _infer_name_and_role(*args) 
 56          return _autoproperty(func, name, role) 
 57      else: 
 58          name, role = args 
 59          return lambda func, n=name, r=role: _autoproperty(func, n, r) 
 60   
 61   
 62 -def _infer_name_and_role(method): 
 63      n = method.__name__ 
 64      if n[0] == "_": n = n[1:] 
 65      role, name = n[:3].lower(), n[3:] 
 66      if name[0] == "_": 
 67          name = name[1:] 
 68      else: 
 69          name = name[0].lower() + name[1:] 
 70      assert role in ("get", "set", "del") 
 71      return name, role 
 72   
 73 -def _autoproperty(method, name, role): 
 74      ## this is the way it is supposed to be done: 
 75      #locals = inspect.stack()[2][0].f_locals 
 76      ## but that breaks (in python 2.5) so we do it the dirty way: 
 77      locals = _getframe(2).f_locals 
 78      prop = locals.get(name) 
 79      if prop is None: 
 80          kw = {"f%s" % role: method, "doc": method.__doc__} 
 81      else: 
 82          kw = {"fget": prop.fget, "fset": prop.fset, "fdel": prop.fdel, 
 83                "doc": prop.__doc__,} 
 84          kw["f%s" % role] = method 
 85      locals[name] = property(**kw) 
 86      return method 
 87   
 88   
 89   
 90  if __name__ == "__main__": 
 91 -    class Test2(object): 
 92   
 93          _foo = None 
 94          _foobar = None 
 95   
 96          @autoproperty 
 97 -        def _get_answer(self): 
 98              """A read only property.""" 
 99              return 42 
100   
101          @autoproperty 
102 -        def setFoo(self, val): 
103              """A dummy property. 
104   
105              To get this property, use self.foo or self.getFoo(default_value). 
106              """ 
107              self._foo = val 
108   
109          @autoproperty 
110 -        def getFoo(self, ifNone=None): 
111              r = self._foo 
112              if r is None: return ifNone 
113              else:         return r 
114   
115          @autoproperty("foo_bar", "get") 
116 -        def GetFooBar(self): 
117              return self._foobar 
118   
119          @autoproperty("foo_bar", "set") 
120 -        def SetFooBar(self, val): 
121              self._foobar = val 
122   
123      t2 = Test2() 
124