keyword

What is the significance of the positioning of the const keyword when declaring a variable in Objective-C, for example: extern const NSString * MY_CONSTANT; versus extern NSString * const MY_CONSTANT; Using the first version in assignments produces warnings about "qualifiers from pointer target type" being discarded so I'm assuming that the second version ensures that the pointer address remains the same. I would really appreciate a more definitive answer though. Many thanks in advance! In the first case, you are declaring a mutable pointer to an immutable const NSString object, whereas in the

Could you please give me the exact concept of the keyword "auto" in a C program. When i gone through one book "Deep C secrets" , got the below quote. The auto keyword is apparently useless. It is only meaningful to a compiler-writer making an entry in a symbol table—it says this storage is automatically allocated on entering the block (as opposed to global static allocation, or dynamic allocation on the heap). Auto is irrelevant to other programmers, since you get it by default. Laurence Gonsalves auto isn't a datatype. It's a storage class specifier, like static . It's basically the opposite

Does anyone know if there is any builtin python method that will check if something is a valid python variable name, INCLUDING a check against reserved keywords? (so, ie, something like 'in' or 'for' would fail...) Failing that, does anyone know of where I can get a list of reserved keywords (ie, dyanamically, from within python, as opposed to copy-and-pasting something from the online docs)? Or, have another good way of writing your own check? Surprisingly, testing by wrapping a setattr in try/except doesn't work, as something like this: setattr(myObj, 'My Sweet Name!', 23) ...actually works!

Many of the books that I am reading use keyword const when the value of a variable should not be modified. Apart from specifying to readers of the code that you may cause errors if you modify this variable (you can use comments to do this), why would you need that keyword to be a part of any programming language? It seems to me that if you don't want a variable modified, simply don't. Could someone clarify this for me? Apart from specifying to readers of the code that you may cause errors if you modify this variable(you can use comments to do this) Not "may"; will cause errors in your program.

I'm dreaming of a Python method with explicit keyword args: def func(a=None, b=None, c=None): for arg, val in magic_arg_dict.items(): # Where do I get the magic? print '%s: %s' % (arg, val) I want to get a dictionary of only those arguments the caller actually passed into the method, just like **kwargs , but I don't want the caller to be able to pass any old random args, unlike **kwargs . >>> func(b=2) b: 2 >>> func(a=3, c=5) a: 3 c: 5 So: is there such an incantation? In my case, I happen to be able to compare each argument against its default to find the ones that are different, but this is

I need to design a class where one property name has to be return , but when I create a property name like return then I get an error. After some research I found out that one can use a reserved keyword as a property or variable name by adding a @ prefix in C#, or by enclosing it in square brackets [] in VB.NET. For example: var @class = new object(); So here is my class design code. public class Person { string _retVal; public string @return { get { return _retVal; } set { _retVal = value; } } } ... Person p = new Person(); p.@return = "hello"; Now I am not getting any error, but when I try