Subj : Re: Looking for Spidermonkey equivalent of Mozilla/DOM trick...
To   : Igor Bukanov <igor@fastmail.fm>
From : Anton van Straaten <anton@appsolutions.com>
Date : Sat Nov 29 2003 07:13 am

Igor Bukanov wrote:
> Anton van Straaten wrote:
> 
>> Igor Bukanov wrote:
>>
>>> Anton van Straaten wrote:
>>>
>>>> Since this program is already structured around setTimeout, I'm 
>>>> wondering if there are any easy tricks similar to setTimeout that I 
>>>> can use under Spidermonkey without DOM?  I could implement a 
>>>> trampoline-style top-level loop and do this myself, I'm just looking 
>>>> for a lazy way out.
>>>
>>>
>>>
>>>
>>> What about pure EcmaScript solution like:
>>>
>>> var functionToContinue = callTheProgram();
>>> while (functionToContinue != null) {
>>>   functionToContinue();
>>> }
>>>
>>> where you program instead of calling setTimeout and returning would 
>>> simply return function to continue that would be called from the top 
>>> level?
>>
>>
>>
>> Thanks, that's more or less what I meant by a "trampoline-style 
>> top-level loop".  It would work, but the problem in this case is that 
>> the program in question is not currently set up to do this, and would 
>> require some restructuring.  So I was hoping for a shortcut...
> 
> 
> But why does it need any restructuring? In the following example the 
> only restructuring that is necessary compared with version in the 
> <script> tag is additional code at the bottom of the file.

That's a nice setTimeout replacement, thanks!

The restructuring I was thinking of is because the program doesn't 
currently have a single top-level function - it saves a continuation at 
each step, and can be paused at any time.  This allows the user to pause 
the program, interact with it and change parameters, and then continue 
the recursive computation where it left off.

Currently, continuing a paused computation simply invokes the last saved 
continuation.  To implement a top-level loop, it would instead need to 
invoke a top-level function, which would invoke the continuation and 
then enter the loop.  I was also thinking in terms of removing 
setTimeout completely, which would require other changes to the 
internals of the program (now that I've thought about this, I may still 
do it just to simplify the code.)

Regards,
Anton

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