Ya as far as Ragel code generation goes you shouldn't need to p, pe, or data available in the write init context. If I remember right that was due to a combination of Ruby variable scoping/declaration rules and the typical usage pattern of Ragel+Ruby. The Ruby code generator really is a special case for a number of reasons. What we need to a Ragel and Ruby expert to sort it out. I'm not both of those things.

There is also some strange stuff in the java code generator too. Java doesn't have static array data. It makes functions that set the values. But large arrays overflow the max function size so you can't have large static arrays. To get around this the arrays are made using functions (like the compiler does), but they are broken down into smaller parts and concatenated. Ugh. I'm not sure if this would apply to javascript as well.

-Adrian

On 10-10-11 12:14 PM, Dominic Marks wrote:
Hey Adrian,

I haven't but I will do. Thank you.

I'm not sure if the RubyCodeGen::writeInit function is incorrect but
it's quite divergent from the CDCodeGen version. The only problem I had
doing the work, besides a few missed semicolons, was that the write init
directive was trying to initialise pe to the data length. In my testing
script the initialisation and execution stages are in separate functions
and this produced invalid JavaScript (data being undefined at that point).

I assumed I had misunderstood something about the options that can be
given to write init and write exec but after that turned up a blank I
looked at CDCodeGen. I was surprised to find that it didn't include
similar code relating to the end directive. I made my writeInit function
more like CDCodeGen and my problem was resolved.

The code in question:

http://github.com/dominicmarks/ragel-js/commit/7a8e554f2829fbebe04a26837ebb5512314c376b#diff-0


The difference might be related to the concessions you mention, I didn't
look into it too much.

Thanks for Ragel, it's a great piece of software!

Dominic

On 11/10/2010 19:54, Adrian Thurston wrote:
Great, thanks for working on this!

Did you have a look at the java code generator? There were a few
concessions that had to be made in the Ruby code generator that might
not need to be made in JS.

-Adrian

On 10-10-11 04:07 AM, Dominic Marks wrote:
Hi all,

I've got the table code generation strategy working. I'm going to work
on building a set of RL files for testing purposes and then have a crack
at writing a code generation backend that targets modern JavaScript VMs
(e.g. produces JavaScript that best suits a JIT/tracer). If anyone would
like to help with any part of this process, I'd be most grateful.

I've forked Ragel trunk into a github repo while I work on this. There
is a sample script (I translated the maillbox.rl file from the Ragel
distribution) which you can play with if you install Node.js (a
JavaScript application framework powered by Google's V8 VM). Note that
while the sample script uses Node.js for IO, but the code generated is
plain JavaScript. I look forward to being able to use Ragel in the
browser soon too.

Github:

http://github.com/dominicmarks/ragel-js

A diff against Ragel trunk is here:

http://goodforbusiness.co.uk/~dom/ragel-js-20101011.diff
<http://goodforbusiness.co.uk/%7Edom/ragel-js-20101011.diff>

The code is mostly a cut-paste-and-replace from Ruby at the moment. I'll
be tidying it up over the next few weeks, as my time allows. However, it
does at least run one Ragel state machine correctly already.

Mailbox.rl/Mailbox.js:

http://goodforbusiness.co.uk/~dom/mailbox.js
<http://goodforbusiness.co.uk/%7Edom/mailbox.js> (Requires Node.js).

Cheers,
Dom

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