Am So., 25. Apr. 2021 um 22:56 Uhr schrieb Adam Nelson <xxxxxx@nels.onl>:

On 4/25/21 7:34 AM, Amirouche Boubekki wrote:

> As far as I know there is no Scheme implementation that can run on a
> trivial subset of Scheme (that is maximally portable across Scheme
> implementations and Operating Systems), and that is easy to debug
> (breakpoints, step debugger, variable inspection, one step macro
> expansion).

I'm actually working on this! My in-progress Scheme dialect (working
title: Tangled Scheme) has this as its primary goal. It will include a
full language server, linter, and debugger for R7RS Scheme, with
exhaustively-detailed error messages in the style of Rust or Elm.

Very interesting! Is this supposed to be a free-standing implementation or will it be hosted on an existing Scheme?

I don't know if a maximally-simple "reference implementation" of Scheme
is possible, though, although writing one as an interpreter in R7RS
itself would make sense. iirc that's what Marc Nieper-Wißkirchen's
Unsyntax is.

I would call Unsyntax rather a transpiler than an interpreter. It takes programs and libraries written in R7RS+extensions and outputs very simple R7RS (which doesn't need any advanced macro or module system features).