CapyScheme

R6RS/R7RS compiler and runtime written in Rust.

Capy 2.0.0 REPL preview

Capy 2.0.0

Capy 2.0.0 is a large compiler, runtime, and library release.

• Compiler work now centers on the SSA pipeline, SSA lowering, and FASL code artifacts.
• Runtime work includes FFI callbacks, native extension loading, thread interrupts, yieldpoints, conservative stack scanning, UTF-8 API helpers, and improved source/error handling.
• GC work includes configurable trigger policies, adaptive/compact/aggressive heuristics, benchmarks, cache locking, and alignment fixes.
• The object system now has define-class, define-generic, define-method, next-method dispatch, sealed/locked generics, class redefinition, slot helpers, and runtime class/generic descriptors.
• Language and library additions include implicit #%app, define-property, call-in-continuation, terminal support, SRFI-213, and SRFI-64 comparator support.
• The fancy REPL, test runner, package builds, and CI/release automation also received updates for this release.

Goals

• Continuation-Passing Style compiler based on Compiling with Continuations, Continued, with native-code generation and FASL compilation.
• Runtime with support for loading modules, native extensions, and fast GC.
• User-friendly: develop standard library and set of utilities to make using Scheme easier.
• Interactive: Provide a REPL with completion, syntax rendering, bracket matching, and reader diagnostics.

R6RS/R7RS support

Most of R6RS and R7RS-small should be "just working" apart from some bugs. R6RS test-suite from racket/r6rs is used to guide development and at the moment 100% of tests are passing.

To run tests yourself:

$ capy --r6rs -L . -s tests/r6rs/run-via-eval.sps

Thanks

Big thanks to authors of Larceny, Guile and Ypsilon. CapyScheme uses stdlib parts from all of them and takes inspiration from them.