Re: Curious Question

From:

"Balog Pal" <pasa@lib.hu>

Newsgroups:

comp.lang.c++.moderated

Date:

Fri, 20 Mar 2009 14:42:12 CST

Message-ID:

<gpua6j$9b4$1@news.ett.com.ua>

<msr9090@gmail.com>

This works well. Now lets say we dont know how many TYPEs are there
before writing code. defs.h is generated by someother program and
there can be any number of TYPEs.

If it is generated, the easiest is to adjust the generator, so it also
emites a

#define MAIN_LISTS \
     std::list<Type1> type1List;\
      std::list<Typ2> type2List;\

and you put that into main. Though I can't imagine how you would use it in
the code without the programmer knowing the number of types.

I had a situation which somewhat resembled yours: the generator was reading
database schema creating structs for every table (inheriting from RecBase).
In that system I had a polymorphic list and array containers, that solved
all those problems for good. Could read the whole database into a single
list. But it was more practical to make it like:
vector< polylist<RecBase> > db;
that was sized to the number of tables and db[i] had records of a single
table (that were all the same type).

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