Re: hash_map versus unordered_map ... compatibility
On Nov 26, 1:18 pm, karsten <karsten_bur...@gmx.de> wrote:
* in my opinion we should add the specialization for 'hash<char*>' and
'hash<const char*>' to avoid unexpected results. At the moment char*
are simply treated as all other pointers: the address is converted to
a number, but the string value is not used. This differs from the
widely used SGI STL implementation and is not what the user would
expect. As a consequence, find'ing elements with a char* key does not
work. If we would add the two specializations, migration of existing
source code using class 'hash_xxx' to the new containers
'unordered_xxx' would then be much easier and performance much better.
IMO, it should be left as it is. It would be what I would expect from
the proposed, conceptually consistent model. To do otherwise would
undermine the fact that typeof(string) != typeof(char *). A string is
a class. A char * is a pointer. Programmers have allowed creepage that
one is equivalent to the other into their minds. This notion has
always been erroneous, and SGI's STL merely perpetuated it. It might
happen that we really want the left-hand-side (LHS) to be char * and
be treated as such (by comparing two integral values). Then what?
Conceptual consistency, IMO, is far more important than availability
of syntactical shortcuts. Its what allows us to keep things straight
in our minds.
-Le Chaud Lapin-
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