[gameprogrammer] Re: Any C++ macro champions out there?
- From: Stéphane Marchesin <stephane.marchesin@xxxxxxxxx>
- To: gameprogrammer@xxxxxxxxxxxxx
- Date: Thu, 3 Jan 2013 17:41:38 -0800
On Thu, Jan 3, 2013 at 5:33 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx> wrote:
> Normally that would work great Stephane, but if you look at my macro list,
> it's a list of lists.
>
> I agree, if it was a single list i could do multiple passes and do:
>
> // 1 - define class header and member vars and getters / setters
> // 2 - define constructor parameters
> // 3 - define constructor body and then end class declaration
>
> But the problem is that i have multiple classes represented in my list,
> which means i can only do a single pass since i can't do the header for each
> class, then the constructor header for each class, and then end each class.
>
Yeah you can't make that work... Couldn't you turn the
TRIGGEREVENTLIST into TRIGGEREVENTLIST_BEGIN and TRIGGEREVENTLIST_END?
Intuitively that would work.
Stéphane
> In the below, 3 classes need to be generated from the single macro list:
>
> #define TRIGGEREVENTLIST \
> \
> TRIGGEREVENT_BEGIN(PokeEvent, Base) \
> TRIGGEREVENT_ITEM(int, PokeCount, true, 0) \
> TRIGGEREVENT_ITEM(bool, PokeHard, false, false) \
> TRIGGEREVENT_END() \
> \
> TRIGGEREVENT_BEGIN(AnotherEvent, Base) \
> TRIGGEREVENT_ITEM(float, Something, true, 0.5f) \
> TRIGGEREVENT_END() \
> \
> TRIGGEREVENT_BEGIN(UberPokeEvent, PokeEvent) \
>
> TRIGGEREVENT_ITEM(float, UberPokeMultiplier, true, 2.0f) \
> TRIGGEREVENT_END()
>
But why not make it:
>
>
>
>
> On Thu, Jan 3, 2013 at 5:26 PM, Stéphane Marchesin
> <stephane.marchesin@xxxxxxxxx> wrote:
>>
>> On Wed, Jan 2, 2013 at 10:29 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx> wrote:
>> > Any C++ macro champions out there? I'm Trying to figure out how to do
>> > something and hoping i don't have to fall back on code generation or
>> > manual
>> > maintenance :P
>> >
>> > I have a macro list defined like this:
>> >
>> > #define TRIGGEREVENTLIST \
>> > \
>> > TRIGGEREVENT_BEGIN(PokeEvent, Base) \
>> > TRIGGEREVENT_ITEM(int, PokeCount, true, 0) \
>> > TRIGGEREVENT_ITEM(bool, PokeHard, false, false) \
>> > TRIGGEREVENT_END() \
>> > \
>> > TRIGGEREVENT_BEGIN(AnotherEvent, Base) \
>> > TRIGGEREVENT_ITEM(float, Something, true, 0.5f) \
>> > TRIGGEREVENT_END() \
>> > \
>> > TRIGGEREVENT_BEGIN(UberPokeEvent, Base) \
>> > TRIGGEREVENT_ITEM(float, UberPokeMultiplier, true, 2.0f) \
>> > TRIGGEREVENT_END()
>> >
>> > And I want to create a class per trigger event that contains each item
>> > as a
>> > member and also a const & getter and setter for each item within it. I
>> > have
>> > that part working, but I'm stuck on the next part...
>> >
>> > What i need to do next is make a constructor or some kind of
>> > construction
>> > mechanism which contains all the items as parameters to the function,
>> > and
>> > then sets the members to the passed in values.
>> >
>> > The problem I'm hitting is that to do that, I essentially need to loop
>> > through an events item list twice (once for params, once for setting the
>> > members to the param values) before moving onto the next event, but not
>> > sure
>> > how to do that (or even if there is a way).
>>
>> You put all your things in one header, let's call that header
>> listofthings.h:
>>
>> DO_SOMETHING(0, "A")
>> DO_SOMETHING(2, "B")
>> ...
>>
>> then you can include that header multiple times, redefining
>> DO_SOMETHING differently every time:
>>
>> #define DO_SOMETHING(A,B) printf("%d %s\n", A, B);
>> #include "listofthings.h"
>> #undef DO_SOMETHING
>>
>> #define DO_SOMETHING(A,B) table[A] = B;
>> #include "listofthings.h"
>> #undef DO_SOMETHING
>>
>> Stéphane
>>
>> >
>> > Unfortunately, a potential added nail to the coffin is that the
>> > constructor
>> > (or construction mechanism) also needs to include as parameters all of
>> > the
>> > inherited items.
>> >
>> > I really want compile time assurance that when these are constructed,
>> > that
>> > they have all the necessary data supplied to them (so when you add or
>> > remove
>> > items, you get compile time errors about the places in the code you need
>> > to
>> > update).
>> >
>> > Thanks for any insight anyone can provide!
>> >
>> > PS if anyone is interested, I can share the code i have right now to
>> > generate classes with private members and getters and setters, as well
>> > as a
>> > COMPILE TIME calculation of the size of the largest class (so you could
>> > use
>> > it as a parameter to an object pool allocator or something).
>>
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>>
>
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