[Gambas-user] Data Structures like C++

[tobi]

On Mon, 21 May 2012, Benoît Minisini wrote:
> Le 21/05/2012 21:51, Demosthenes Koptsis a écrit :
> > Basic languages have simple data structures like vars and arrays but
> > other languages
> > like c++ with the help of pointers can have advanced data structures
> > like containers etc...
> >
> > see a full list here
> > http://en.wikipedia.org/wiki/List_of_data_structures
> >
> > i wonder if such data structures can be implemented with gambas with
> > pointers and if such an action have any mean for real life
> > applications?
> >
> > Is it possible to have such data structures in gambas?
> > How about some of these to be part of the core libraries?
> 
> Some data structures are missing, but not so many as you may think at 
> first sight.
> 
> If they are implemented, I don't think they will go inside the 
> interpreter, to keep its size small (it is already too big for my 
> tastes), but in an extern component.
> 
> * Map/Associative array/Dictionary
> * Hash
> 
> Use a Collection in both case. If the key is not a string, you must find 
> a way to identify your key with a unique string.
> 
> * Multimap
> 
> Use a Collection whose values are arrays.
> 
> * List
> 
> Use an array. Since CPU have now one, two, three... memory caches, 
> arrays as almost always faster than linked lists.
> 
> * Set
> 
> One could use a Collection to emulate it: by transforming a value into a 
> string key, we can assume that the value belongs to the set if the 
> collection has something associated with the key.
> 
> But it would be better to add a Set native class with a native 
> implementation (in C. Stop with C++!).
> 
> * Multiset
> 
> Same remarks (the value is associated to its number of occurence in the 
> collection).
> 
> * Priority queue
> 
> Is it worth having a native implementation for that? I don't think so. A 
> implementation in Gambas should be enough.
> 
> * Queue
> * Deque
> * Stack
> 
> Use an Array. The Push() and Pop() methods can help.
> 
> * String
> 
> We have strings of characters. Is something else really needed?
> 
> * Tree
> * Graph
> 
> Native implementation of that would be interesting.
> 
> Any volunteer? :-)
> 
> -- 
> Benoît Minisini
> 
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Heh... I was once working on reversing the collatz conjecture from a given integer - using a
(halfways) binary tree.

Graphs would in fact be interesting to implement but what is to be cleared up before anyone could
think about volunteering:
* Are trees restricted to their number of children?
* The same for graphs: restrictions on the number of edges?

The latter, I never used in programming (read of them a bit in mathematics). What could they be used
for generally? Representing town maps? :)