On Fri, Sep 19, 2014 at 02:41:31AM +0000, Wang Lei (ERIAN) wrote: > Hi, everyone: > > I really believe that python is a great language but assignment and callable > are not flexible: > > I wish that I can do this: > > class matrixArray(list): > bla bla bla > def __call__(self, rid, cid): > return self.head[rid][cid]
You can. __call__ is used for making objects a callable, function-like object. C++ calls them "functors". (Not the same thing as what Haskell calls functors!) > Once I call mat(1,1), I can get a result. but I want it more a value not a > reference. You want to change the entire execution model of Python? Why? Like most modern languages, such as Ruby, Java (mostly), and Javascript, Python values are references, not unboxed low-level primitive values. > Considering "mat(1,1) = 5" expression, I wish the parser can > dynamically map "mat(1,1)" to reference of value of that "or anonymous > reference" or reference defined in class. I'm afraid I don't understand what you are trying to say, but if you want to assign to individual items in a matrix, use indexing, not function call: mat[1, 1] = 5 will work perfectly once you add a __setitem__ method to your matrix class. > I don't want to modify the > lexical parsing in C++ but failed after trying different method in > pythonic ways: What does C++ have to do with this? > decorator: fun -> object mapping, because it just substitute function > name with new function and cannot read "self" object. > > I wish python developers could think of an idea to update the lexical > parsing method or simply provide us a tool to modify it in python > context. I think that their answer will be: "We will not complicate the language, making our job enormously harder, and Python much harder to learn and use, just because a beginner to Python who doesn't understand what the language can do or how to use it, wants to program in C++ instead of Python. If you want to program in C++, use C++. If you want to program in Python, learn Python." What do you expect to do with: mat(1, 1) = 5 that cannot be done with this instead? mat[1, 1] = 5 -- Steven _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
