[Haskell-cafe] More on the random idea

[Rodrigo Queiro]

>
> As far as I know, hs-plugins works by taking an expression, writing it
> to a file, calling GHC to parse it, transform it to Core, optimise it,
> transform it to STG, optimise it, transform it to C--, optimise it,
> transform it to ANSI C, optimise it, pass it to GCC, compile it, link
> it, and *then* using the GHC runtime linker to load the generated object
> code into memory, type-check it, and, finally, execute it.


Don't forget the Evil Mangler, which optimises the compiled assembly!

http://www.cse.unsw.edu.au/~chak/haskell/ghc/comm/the-beast/mangler.html

On 26/05/07, Andrew Coppin <andrewcoppin at btinternet.com> wrote:
>
> Donald Bruce Stewart wrote:
> > The #haskell people have been working on this for about 3 years now.
> > The result is the 'runplugs' program, which I've talked about in
> > previous mails.
> >
> >     http://www.cse.unsw.edu.au/~dons/code/lambdabot/scripts/RunPlugs.hs
> >
> > It uses hs-plugins for the evaluation, along with the points about IO
> > prevention via type checking, resource limits controlled by the OS,
> > language extension preventions, and a trusted (audited) module base.
> >
> > The security mechanisms were briefly described in the 2004 hs-plugins
> > paper, if I recall, but otherwise, I don't think we've documented the
> > techniques. Maybe we should, as many issues have been encountered over
> > the years, further and further constraining the kinds of things that are
> > allowed.
> >
>
>
> For me, the unfortunate thing is that there seems to be no interpreter
> for Haskell written in Haskell. (Except for GHC, which is *huge*.) We
> have a Haskell parser [which is complex beyond usability], but no
> interpreter. It would be nice if one existed, and I'm trying to
> implement one... but on the other hand, one doesn't want to say to
> people "hey, come learn Haskell, try this web interpreter" and then have
> them find it doesn't implement Haskell precisely. So it looks like I'm
> stuck with present technology - and that essentially means GHC. (Other
> compilers? What other compilers??)
>
> As far as I know, hs-plugins works by taking an expression, writing it
> to a file, calling GHC to parse it, transform it to Core, optimise it,
> transform it to STG, optimise it, transform it to C--, optimise it,
> transform it to ANSI C, optimise it, pass it to GCC, compile it, link
> it, and *then* using the GHC runtime linker to load the generated object
> code into memory, type-check it, and, finally, execute it.
>
> OTOH, GHCi just takes an expression, parses it and interprets it. This
> appears to be a *much* more lightweight approach. I have had some
> success in using the GHC API to write a program that is essentially GHCi
> - you type stuff in, it executes it. Now, if I could write a complete
> full-featured HTTP server and feed that into it instead of stdin and
> stdout, I could make a web server for executing Haskell... But, hmm,
> that's not going to happen any time soon.
>
> ...or, I could use GHC -e as I described earlier. But I have to look at
> figuring out how to prevent it doing Bad Things. (Lambdabot gives me an
> idea. Write a module that imports all the stuff you might want
> interactively, and process the user-supplied script to make sure it
> doesn't issue any imports, and then you can precisely control what
> functions the code can call.)
>
>
> Whatever... I'd just like to see an online way to run Haskell, and since
> the Lambdabot webpage still shows no sign of working...
>
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