Web vs Native (was Re: HTML5 limitations?)

[Mark Waddingham]

On 2017-07-28 18:28, William Prothero via use-livecode wrote:
> on myRequest
>    —send a POST or GET request, whatever, with a callback handler 
> specified.
>    —display a mask that inhibits new mouse clicks and sets a busy icon.
> end myRequest
> on myCallbackHander myReturnData
>   —do whatever you want with myReturnData
> end myCallbackHander
> 
> But then again, I’m not a master of javascript, so there may be other 
> issues.

I think it is mainly the thought process which goes with having to do 
things in this 'threaded style' - for simple things it is fine, but it 
can get unwieldy pretty quickly for long running sequences of stuff. 
 From an abstract perspective, at the very least, it *should* be possible 
to make this more natural (e.g. C# has an 'async' concept - which is 
basically a bit like out wait but more focused) so that is one angle 
here.

>> Although I am one of the people calling for more browser widget 
>> development...
>> 
>> I have my doubts about the ability to make it synchronous with LC.

It is definitely possible - the fact it is not is related to a technical 
detail in the way the engine interoperates with CEF (and the other 
browsers). However, being possible says nothing about the difficulty of 
getting it to work or ensuring it continues to work!

The HTML5 engine IS synchronous so that gives at least a suggestion that 
is should be possible (although, admittedly, the HTML5 engine IS 
JavaScript so there's no 'world-boundary' to be concerned about in that 
instance).

At the end of the day, it might not be that making it synchronous *is* 
the solution, but instead tweaking engine syntax and semantics to make 
it easier to deal with this asynchronicity.

e.g.

on mouseUp
   async do "..." as javascript into tVar
   -- implicit wait until tVar has been set
   put tVar into field 1
end mouseUp

Note, this is just pseudo-code for the idea. The hardest part about 
doing the callback thing is that it splits up the critical sequence of 
actions you are trying to code into lots of bits separated by cruft (the 
handler definitions). This reduces readability, and maintainability 
which is something we really don't want. i.e. The problem you are trying 
to solve is obfuscated by the technical baggage needed to solve it.

Warmest Regards,

Mark.

-- 
Mark Waddingham ~ mark at livecode.com ~ http://www.livecode.com/
LiveCode: Everyone can create apps