Function Pointers For Newbies

(a.k.a What are those smilies doing in my code and how do I use them right)

Most mudlib objects, especially simple ones, only consist of a
single function: setup().  It is important to understand that this is _not_
just a list that tells what the object is like; instead it is a
list of commands that gets executed right after the object is made that
_makes_ it into the type of object you want it to be.

For example, all objects start with a default long description.
set_long() then changes the description to whatever you want.

Why is this distinction important?  Consider a statement like:

set_long("A quickly changing display which currently reads: " + random(1000));

If you try this in a test object, you will find that each object you clone
has it's own number, but that that number never changes.  This is
because the random() function is only called _once_ when setup() is called,
and the long description is set to that string.  After that, whenever you
look at the object, you see the string that the long description was set to.

Now, to get the number to change every time you look at it, try:

set_long( (: "A quickly changing display which currently reads: " + random(1000) :) );

The (: :) means "Don't run this now, just store it and run it when you
need it".  Now, every time you look at the object, random() is used to
get a new random number, and a new description is returned,
so the object looks different every time you look at it.

Another common way to use function pointers is to simply use:

set_long( (: long_function :) );

which means that whenever the long description is needed, call the function
'long_function' and use whatever it returns.
long_function can then be as complex as you want, for example:

string long_function() {
    int x, y, z;
    x = random(100); y = random(1000); z = random(10000);

    return "There are 3 quickly changing numbers on the panel, which read: " + x + ", " + y + ", and " + z + ".\n";
}