Re: [Boost-Users] A Static Map?

From: Duane Murphy (duanemurphy_at_[hidden])
Date: 2002-01-14 18:35:09

--- At Mon, 14 Jan 2002 14:29:39 -0800, Mike Thompson wrote:

>
>Maybe I missed something, but doesn't an std::map<keytype, valuetype> do
>this??

Yes, sort of. But std::map<> is big, heavy, slow and dynamic. This is
totally static data that doesnt change for the lifetime of the
application. A simple lookup table. The table requires no dynamic memory
allocations.

Really what this template class would do would be to hide the searching
of the table as well as provide a single source of the search code.

>  Duane Murphy <duanemurphy_at_[hidden]> wrote: I have learned a lot about
>templates and library programming from reading
>and using the Boost code. Recently I have been finding myself doing
>something that I would call Static Maps. Basically I would like to use an
>array of structs as if it were a map or associative array.
>
>Does boost have anything like this or can anyone recommend something like
>that?
>
>Here is a simple example:
>
>struct entry 
>{
>    const char* key;
>    const char* value;
>};
>
>const entry entries[] =
>{
>    { "one", "Hello" },
>    { "two", "World" },
>    { "three", "!" }
>};
>
>
>{
>    some_type the_map = make_static_map( entries );
>    const char* word = the_map[ "one" ];
>
>}
>
>This is a real poor example, but shows the idea. The struct could be any
>types that are less-than comparable; maybe there is some special
>arrangment of key and type. But the idea is there. I would like to be
>able to lookup items in a static array of items using array notation
>(other than numerically indexed).
>
>For extra credit, the interface would be writeable also; aka a fixed
>array space map.
>
>Any idea? Comments? Suggestions?
>
>..Duane