[TYPES] subtyping of mutually recursive algebraic data types

[Aaron Gray]

On Fri, 17 Jun 2022 at 18:00, Mark Sheldon <sheldon at alum.mit.edu> wrote:
>
> We deal with this topic in our book, Design Concepts in Programming Languages (https://urldefense.com/v3/__https://mitpress.mit.edu/books/design-concepts-programming-languages__;!!IBzWLUs!VMszV1CswUJMokl4bq4nZ2MiwksJZ8Yv9-8MP3BH1wxJXGi_EuLL1aoglnuW3Ox9O6RYStjSg30TbV4z0GKs7OlslS5BDu4RWPR2mA$ ).  See Chapter 12.  There is a section on “Subtyping of Recursive Types on pages 706–707,

Mark, thank you I have ordered a copy of your book, I have a copy of
TAPL but Chapter 12 seems pretty limited.

Thanks for the other two papers,

Aaron

>
> Here are relevant references given in the Notes section of Chapter 12 on page 767:
>
> Kozen, Palsberg, Schwartzbach.  Efficent recursive subtyping.  POPL 93.
> Gapayev, Levin, Pierce.  Recursive subtyping revealed. ICFP 00.
> Pierce.  Types and Programming Languages. MIT Press.  2002.  Chapter 12.
>
>
> I hope this is useful!
>
> -Mark
>
> Mark A. Sheldon
> Associate Teaching Professor
> Department of Computer Science
> Tufts University
>
> On 17Jun, 2022, at 03:40, Aaron Gray <aaronngray.lists at gmail.com> wrote:
>
> [ The Types Forum, http://lists.seas.upenn.edu/mailman/listinfo/types-list ]
>
> I am interested if there is any work on the subtyping of mutually
> recursive algebraic data types. I am wanting an algorithm for purposes
> of implementing an object oriented programming language with ADT's
> which lower onto a virtual class implementation which can support
> mutually recursive behavior, but need the typ checking and inference
> at the ADT level.
>
> Theres a number of papers and projects in this area I have came across
> but none of them actually tackle algebraic data types properly let
> alone mutually recursive ones.
>
> A number inspired by Stephen Dolan's PhD Thesis and MLsub, his implementation.
>
> - Practical Subtyping for Curry-Style Languages by Rodolphe Lepigre
> and Christophe Raffalli - subml - https://urldefense.com/v3/__https://github.com/rlepigre/subml__;!!IBzWLUs!ROzY30gWHR0LPvTTZLo_Ep7ErCu0LhX2jrPKbFJ9uhVgSSx659leOfq_pNrPSAGgLExea89yhX9iVce14nA987dFVoNzXhSpE6cZJg$
> - The Simple Essence of Algebraic Subtyping, Lionel Parreaux and
> simple-sub implementation - https://urldefense.com/v3/__https://github.com/LPTK/simple-sub__;!!IBzWLUs!ROzY30gWHR0LPvTTZLo_Ep7ErCu0LhX2jrPKbFJ9uhVgSSx659leOfq_pNrPSAGgLExea89yhX9iVce14nA987dFVoNzXhS4dNcEiw$
> - A Mechanical Soundness Proof for Subtyping Over Recursive Types
> Timothy Jones David J. Pearce -
> https://urldefense.com/v3/__https://github.com/zmthy/recursive-types__;!!IBzWLUs!ROzY30gWHR0LPvTTZLo_Ep7ErCu0LhX2jrPKbFJ9uhVgSSx659leOfq_pNrPSAGgLExea89yhX9iVce14nA987dFVoNzXhRACugkxw$
>
> None of these seem to deal with mutually recursive data types.
>
> I am interested in the papproach of using codata/coinduction and
> coalgebras and possibly bisimulation in order to deal with the
> mutually recursive nature of real world mutually recursive algebraic
> data types like for instance AST's of real world complex computer
> languages.
>
> Any projects, papers, thoughts, or implementations would be of interest.
>
> Regards,
>
> Aaron
>
>


--
Aaron Gray

Independent Open Source Software Engineer, Computer Language
Researcher, Information Theorist, and amateur computer scientist.