HTML5 deployment: progress comes into sight

jonathandlynch at gmail.com jonathandlynch at gmail.com
Wed May 31 19:07:07 CEST 2017


A callback is not synchronous, his point was that it would be nice to communicate synchronously between LC and JS, rather than use complex callback chains.

I agree with him, but I don't think there is a universal way to do that, just because some things in JavaScript, like rendering an image or using a webworker, are inherently asynchronous.

Sent from my iPhone

> On May 31, 2017, at 12:36 PM, Roland Huettmann via use-livecode <use-livecode at lists.runrev.com> wrote:
> 
> @BR wrote: ... "What's very difficult, as you write in detail, are
> "callbacks" for _synchronous_communication..."
> 
> Callback functions?
> 
> In my mind, a "callback" is always asynchronous -? Let us say in Javascript
> - passing the function name and parameters of Javascript through LCS/LCB
> and then somehow the result is put into a variable while I am continuing
> processing other stuff. Maybe I am wrong? I am calling a server, waiting
> for the result, but I could wait forever and the result will possibly never
> come. So it would be blocking doing other things. A callback would free me
> from waiting for nothing. Is this a right definition for "callback"?
> 
> What defines "callback"? I could understand though that I am calling a
> function in the browser widget (using the "callback" name of the function)
> which will be executed through Javascript and will be returning a value for
> further processing. What means "synchronous" or "asynchronous" in this
> context?
> 
> Again, in my mind, a callback is when I send off a parcel to my friend with
> an instruction to tell me that it arrived and the confirmation of arrival.
> The confirmation is the callback. Then I know my friend received the
> parcel. Or in another analogy, I am calling someone by phone asking to call
> me back. The person may call immediately or may call never or in a couple
> of days. This is asynchronous.
> 
> How would a callback become synchronous? Is it then still a "callback"?
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