A little Levure-oriented question

J. Landman Gay jacque at hyperactivesw.com
Wed Feb 21 14:50:53 EST 2018

On 2/21/18 12:58 PM, Graham Samuel via use-livecode wrote:
> But if there’s no code in the UI stack, how do the handlers in the SOS know what object has invoked them?

A behavior acts as though every object with the assigned behavior has 
that script copied into itself. That means that "me" always refers to 
the object with the behavior, and each instance of the behavior keeps 
its own separate script local variables. Without a behavior, you'd need 
to put a mouseUp handler that calls "doSomething" into each button, and 
doSomthing would live in a card or stack script. Then doSomething would 
have to get the name of the target to know the caller, and also keep 
track of any local variables independently.

I'm working with a project that uses a lot of script-only stacks. It 
uses a combination of embedded ("normal") scripts and SOS. Handlers that 
only apply to a single object or card are usually written into the stack 
or control as usual. Handlers that are used in more than one place are 
moved to SOS either as behaviors or libraries. Libraries work like 
stacks in use, behaviors can be shared among different objects. For 
example, we have a behavior that creates and manages a native scroller 
on mobile. Whenever we need a native scroller for a field, we assign 
that SOS as a behavior of the field. The field itself has no script, the 
behavior does it all.

 From what I've read so far here, you don't actually have to convert 
everything to script-only stacks. You can convert some, or none, or all. 
I believe Trevor said that you can use other functions outside of the 
script management features -- for example, built-in functions that 
compile the app or do auto-update, etc. Your point about not needing SOS 
for a single developer is, I think, correct. But even if you're the only 
one working on a stack, you may still want to track changes and updates 
in a versioning system. Whatever you want to track, you'd convert to a 
SOS because versioning systems work only with text files.

I haven't made the move myself either, but I'm interested in what is 
possible so I've been following this thread. Don't feel bad about 
asking, some of us are lurking.

Jacqueline Landman Gay         |     jacque at hyperactivesw.com
HyperActive Software           |     http://www.hyperactivesw.com

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