direct messaging and broadcasting and how to protecting a behavior from inadvertent broadcast messages
send call d4 d5 d6 behavior

  send vs call
Big concepts:

--  In D4+ and with regular parent/child you can always use direct
messaging, such as "SomeFunction(someObject)". In later versions this can
work with sprite and scriptmember objects too. If the message cannot be
handled there will an error.

--  The three new broadcasting methods in D6 (sendAllSprites, sendSprite,
and call) have two advantages: they can send messages to multiple objects,
and if the message cannot be handled there won't be any error.

--  The more objects you're passing messages to, the more microcycles.
Other things being equal, don't sendAllSprites if you can sendSprite, and
don't sendSprite if you can call to a partner behavior. (These calculations
pale beside media-loading and display calculations, though.)

--  The big danger with broadcast messages is namespace collisions. If
you're broadcasting a message, please make sure you're using a unique
name... "sendAllSprites(#init)" could have unintended consequences!

btw, one trick you can use for protecting a behavior from inadvertent
broadcast messages is to include a self-reference argument:

  on PrivateMethod me, caller
    if caller <> me then exit
    --  do private things

This requires the extra line in each protected handler, as shown above, and
also requires a slightly different calling syntax from inside the behavior:

  on beginSprite me
    PrivateMethod me, me

Because a broadcast message won't know the specific identity of objects
it's talking to, it won't be able to include that self-reference argument.



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