[self-interest] goals (was: dynamic deoptimization)

[David Ungar]

Thanks, glad it wasn't just my own obtuseness. 

When I need a parser, I write my own using a particular pattern that works well for me: easy to debug, easy to generate clear error messages for the user, easy to map the generated stuff back to source and v/v. 

-- David (tapped out on my iPhone; blame it for any typoze;-)

On Dec 13, 2011, at 10:24 PM, Casey Ransberger <casey.obrien.r at gmail.com> wrote:

> PEGs are painful to debug. All that memorization creates a lot of instance state. This is presently a given. I've experienced the same problem with OMeta, PetitParser, and Treetop. 
> 
> I would offer: PEGs are relatively new, at least compared to CFGs. They make a lot of things that are hard to do with CFGs really easy. It's likely, given that they provide a different set of trade-offs from what one gets with traditional compiler design, that we'll eventually find better ways to deal with debugging them.
> 
> Another way of saying this is: test methodology will always follow at least slightly behind development methodology. 
> 
> But yeah, debugging an OMeta grammar is a pain in the ___:)
> 
> On Dec 13, 2011, at 9:46 PM, ungar at mac.com wrote:
> 
>>  
>> Have you ever used OMeta and tried to debug your OMeta program?
>> 
>> I tried, very briefly, and was put off by the debugging experience.
>> But maybe you've had better luck.
>> 
>> - David
>> 
>> 
>> 
>> On Dec 12, 2011, at 5:48 PM, Casey Ransberger wrote:
>> 
>>>  
>>> 
>>> Top post: nested interpreters makes me think about OMeta. Just a thought. 
>>> 
>>> On Dec 12, 2011, at 3:28 PM, "Jecel Assumpcao Jr." <jecel at merlintec.com> wrote:
>>> 
>>>>  
>>>> Thorsten Dittmar wrote:
>>>> 
>>>> > I'm interested in general , to get self more selfish. If we would be able to
>>>> > manifest the principles of self even more accurate and more evident, that
>>>> > would be something great. For that reason I thought that the Klein VM would
>>>> > be one of the right steps.
>>>> 
>>>> It is a very good idea to be able to use what we have learned. That is
>>>> how we got Self in the first place, and before that Smalltalk-80 from
>>>> -78/-76 and those from -72/-74. Commercialization from Smalltalk-80 as
>>>> it was, so the lessons from Ark couldn't be applied.
>>>> 
>>>> Klein tried to implement the stuff learned after Self 1, 2 and 3 and
>>>> then Squeak. My main problem with that project is that it uses
>>>> generative coding (think macros) to get more done with less but this is
>>>> done in a system that is unaware of this. So you get generated code side
>>>> by side with hand written stuff and it takes a very long time to figure
>>>> out which is which if you weren't the one who created them in the first
>>>> place. This also tends to create many copies of the same stuff (made
>>>> worse by the fact that there are several parallel experiments in the
>>>> same code) and it takes a while to figure out which ones are used where.
>>>> 
>>>> Since Klein has not been touched since 2006, my own strategy will be to
>>>> try to include what I can learn (and have already learned) from it in a
>>>> new system. My PhD project is to implement a self sustained system in a
>>>> way that is understandable by generating code from nested interpreters
>>>> (which are easy to write and understand) with partial evaluation (even
>>>> if a mostly faked one, like in Pypy where tracing does the job a partial
>>>> evaluator would do). One way a system can be defined in itself is
>>>> through reflection - meta-objects. That leads to the problem of an
>>>> infinite tower of interpretation, but as I just said nested interpreters
>>>> are exactly what I hope my system will be able to handle.
>>>> 
>>>> The metric to measure the success of my PhD project will be how much of
>>>> Klein's funcionality it will have compared with how much smaller it will
>>>> be to do it.
>>>> 
>>>> The language I have been using is Squeak in order to play nice with
>>>> several projects that are interesting to me. But I think it might be
>>>> better to include more options, like Self 4 and some even simpler
>>>> version.
>>>> 
>>>> -- Jecel
>>>> 
>>> 
>> 
> 
> 
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