Best Practices

[Cubist at aol.com]

sez esmale at welshpiper.com:
>* Functions: From what I read, a function can be called by any other 
>handler in a given script. Is it therefore best to define functions at
>the beginning of a script, before any event handlers? If I want to open
>a function up to the whole application, should I define it in its own stack?
   The short answer: As far as Rev is concerned, it makes no difference where 
a function is in its script. As well, if you want your function to be usable 
by anything in a stack, that function should go into the script of the stack 
itself.
   The longer answer: When you use a function in a script, Rev starts out 
looking for the function in that script. If the function isn't there, Rev moves 
up the message-passing hierarchy until it finds a script that contains the 
function.
   As an example, let's say that you've got a button named "Fred", which 
lives on a card named "George" in a stack named "Zelda". Let's say that button 
"Fred" has a mouseUp handler which uses the function SuperTweak. When you click 
on button "Fred", Rev will first check the script of "Fred" to see if the 
SuperTweak function is in it. If SuperTweak is there, great -- Rev will happily use 
the SuperTweak function in button "Fred". But if SuperTweak *isn't* in the 
script of button "Fred", Rev moves up the message-passing heirarchy -- which, in 
this case, means it looks in the script of card "George". If Rev finds 
SuperTweak in the script of card "Fred", it uses that SuperTweak and all is well; if 
not, it's time to move up the message-passing hierarchy once again, which 
means looking in the script of stack "Zelda". If Rev finds SuperTweak in the 
script of stack "Zelda", great! Rev then uses that SuperTweak. But if SuperTweak 
isn;t even *there*, well, that's the end of the line -- there's nowhere else in 
the message-passing hierarchy to *go* -- so Rev will put up a dialog box on 
the screen which complains that Rev doesn't understand "SuperTweak".
   At this point, it is worth noting that there is something called a 
"backscript" which can complicate matters. However, backscripts don't exist by 
default; unless you've explicitly created one, you can safely ignore backscripts.