Formal specification of ATS2 abstract syntax tree (Template ATS2?)

[Shea Levy]

Hi all,

I was wondering, would it be possible to model the ATS2 abstract syntax
tree as ATS2 types, and use that to implement the ATS2 version of
Template Haskell? What would be involved in that kind of project, where
would I start?

Cheers,
Shea

[Hongwei Xi]

I am very glad that you brought up the issue.

Note that the keywords "`(" and ",(" and "%(" are still kept
in ATS2 in the hope of supporting TH-style of meta-programming :)

I co-authored the following paper about 10 years ago:

http://www.cs.bu.edu/~hwxi/academic/papers/JFPmp.pdf

I actually implemented in ATSproto, the first released version of

ATS, the system formalized in the above paper, which is more
ambitious than Template Haskell (TH) in terms of type-checking.

By the way, ATSproto also supported OOP; it was really messy and bulky :)

If you are interested, I would suggest that you target only the functional core of
ATS at first. There may be complications due to the support for flat data representation
in ATS2.

Static typechecking is wonderful, but it is often too complicated for such a template

system. So trying to support run-time typechecking on generated syntax trees seems

to be sensible way to control complexity.

Lastly, I would like to point out the following paper:

http://www.cs.bu.edu/~hwxi/academic/papers/gpce06.pdf

which is about distributed meta-programming. It is a quite interesting idea.

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[Artyom Shalkhakov]

Hello Shea,

I don't know. Just wanted to chime in and wish you good luck. :-)

I was recently thinking of using metaprogramming together with external constraint solving to allow for type-safe database queries in ATS, in the style of Ur/Web. Basically, add new external sorts "row" and "field label", and a few external static functions for constructing row sorts, and then implement some data structures that would be indexed by these sorts. The disjointness proofs of record field labels would be handled externally.

At first, I was thinking of using some form of a preprocessor for this. But TH-style metaprogramming would be much easier to deal with, I assume.
 

Cheers,
Shea

[Shea Levy]

On Thu, Oct 23, 2014 at 09:17:11PM -0400, Hongwei Xi wrote:
> I am very glad that you brought up the issue.
>
> Note that the keywords "`(" and ",(" and "%(" are still kept
> in ATS2 in the hope of supporting TH-style of meta-programming :)
>
> I co-authored the following paper about 10 years ago:
>
> http://www.cs.bu.edu/~hwxi/academic/papers/JFPmp.pdf
>
> I actually implemented in ATSproto, the first released version of
> ATS, the system formalized in the above paper, which is more
> ambitious than Template Haskell (TH) in terms of type-checking.
>
> By the way, ATSproto also supported OOP; it was really messy and bulky :)
>
> If you are interested, I would suggest that you target only the functional
> core of
> ATS at first. There may be complications due to the support for flat data
> representation
> in ATS2.
>

What consists of the 'core' here?

> To view this discussion on the web visit https://groups.google.com/d/msgid/ats-lang-users/CAPPSPLpadySc9iA4FsJ5vsmFvLFEo3GgbpTk5cggMTs43TpUyg%40mail.gmail.com.

[gmhwxi]

Essentially, the core consists of

lambda-calculus + datatypes + references.

[gmhwxi]

Today, I located ATS0-proto. It is now available on-line:

https://sourceforge.net/projects/ats-first/

The interpreter for ATS0 is contained in the following file:

https://sourceforge.net/p/ats-first/code/ci/master/tree/atsInterp.ml

It does handle the kind of meta-programming we talked about above.