string literals

[Saaa]

Thanks, so the common use of strings is such that it is best to make the 
default setting 'immutable'.
Then, how about adding the .access property to arrays? (or all types :)
With strings default .access as read only?


>>Why is this? (I expect there to be a nice reason for it, I just down't 
>>know it :)<
>
> That's an interesting question. Now and then I too feel the need of 
> mutable stings, to change their chars, etc, but here Josh Block and the 
> famous Sedgewick explain why immutables are often good:
> http://www.cs.princeton.edu/introcs/33design/
>
> <<
> An immutable data type is a data type such that the value of an object 
> never changes once constructed. Examples: Complex and String. When you 
> pass a String to a method, you don't have to worry about that method 
> changing the sequence of characters in the String. On the other hand, when 
> you pass an array to a method, the method is free to change the elements 
> of the array.
>
> Immutable data types have numerous advantages. they are easier to use, 
> harder to misuse, easier to debug code that uses immutable types, easier 
> to guarantee that the class variables remain in a consistent state (since 
> they never change after construction), no need for copy constructor, are 
> thread-safe, work well as keys in symbol table, don't need to be 
> defensively copied when used as an instance variable in another class. 
> Disadvantage: separate object for each value.
> Josh Block, a Java API architect, advises that "Classes should be 
> immutable unless there's a very good reason to make them mutable....If a 
> class cannot be made immutable, you should still limit its mutability as 
> much as possible."
>>>
>
> Something more:
> - Immutable data works well with multiprocessing
> - it's common in functional style programming allowing more pure functions
> - the GC can manage immutable strings/objects in an efficient enough way.
>
> Bye,
> bearophile