[Laszlo-dev] javascript optimizer

[Benjamin Shine]

Hi, Can.

We're focused on making the object/event/view/network code solid,  
portable, and fast; I don't think we are currently planning on more  
optimizations to the compiler. The javascript emitted by the open  
laszlo compiler already has variable name compression and whitespace  
trimmming. If you look at the code, you'll see bigLongVariableName  
becomes $1.

Michael A. Jackson's rules of optimization steer us here:
1. Don't do it.
2. (for experts only) Don't do it yet.

Tucker has taught me that this means, "Don't optimize until you have  
a clear solution, and don't optimize until you know where the  
performance bottlenecks lie." Wikipedia is helpful here... http:// 
en.wikipedia.org/wiki/Optimization_(computer_science)

That said... it sounds like you're interested in optimizing for  
download size. Is that right? I bet optimization for download size  
could be improved by a careful look at what libraries and components  
are included by the compiler by default. In the 12000 lines of  
javascript that a small compiile produces, there are probably a few  
unneeded inclusions.

If you're interested in optimizing for runtime performance, that  
would be a different thing. Optimization for runtime performance  
should (imho) only be done after vicious profiling; otherwise, how  
would you know where to optimize? My benchmarking work so far reveals  
that runtime performance is very different in the different browsers,  
so then you get into optimizing for a particular runtime. At this  
point in the development cycle of OL4, it's too early for that; we  
need higher quality and consistency across runtimes more than we need  
per-runtime performance optimizations.

And with all that said... a few places in the code have already been  
hand-tweaked; I'm thinking in particular of the CSS engine, in which  
Adam Wolff inlined some function calls. That was for code that we  
*knew* was being called over and over at startup time, and we had  
benchmarks in place to test the optimizations.

It would be interesting to see what a javascript optimizer does with  
the emitted code; feel free to give it a try and let us know what you  
learn. Or clarify exactly what you're trying to optimize *for*, and  
we can advise you further.

-ben


On Jun 12, 2007, at 8:14 AM, Can Barışcan wrote:

> are there plans , or anybody has tried optimizing the javascript  
> code for dhtml runtime, and the app javacript(like gmail has).  I  
> beleive they have to be optimized with the same optimizer because  
> they may use similar names for variables.  Any good optimizer you  
> know of that could shrink the js code, shorten the variable names  
> and reduce the file size?
> Thanks,
> Can

Benjamin Shine
Software Engineer, Open Laszlo / Laszlo Systems
ben at laszlosystems.com