v2.1.0

v2.1.0 — 2026-05-18

This release brings a few refinements to the language, as well as many bug fixes and performance improvements. The CLEVR example is now fully differentiable and includes a new web visualizer.

Language improvments

• def for global constants, like in Clojure
• reduce now also supports the 2-argument form used in Clojure
• sort now accepts tensor arguments
• Macros can now use quasiquoted templates

Runtime

• Distinguish unsupported codegen cases from real bugs when a JIT error happens
• Gracefully bail out when graph exceeds 10K nodes
• --mem-profile flag
• Better error hints for shapes and indexing errors
• Removed unneeded dependencies

Bugfix

• Fixed reduce backward pass by reusing scan_vjp (1ea2fba)
• Dict key loss fix in JIT path: dict keys no longer dropped through the JIT codegen path
• VAG lambda preprocessing: static constants resolved inside lambda bodies before JIT (a496238, 150c663)
• get backward for scalar indices: reverse-mode AD now handles scalar indices correctly (30fe862)
• Slice shape propagation: :axis keyword now properly propagates shape in autodiff (4a779e5)
• Batched matmul gradients: fixed panic with batched tensor inputs (101b290)
• Einsum dimension mismatch: no longer panics on subscript/operand shape mismatch (123ed91)
• No longer panics on 0-dimensional tensor slicing (4b99ff1)
• One-hot bounds check: out-of-bounds indices now return proper error (d6b5883)
• nth out-of-bounds: tensor indexing no longer panics (f39da67)
• Deep layout propagation in scan VJP: nested dicts handled correctly (ed32b3f)
• Lambda scoping in resolve_constants_rec: fixed incorrect constant resolution across lambda boundaries (699148e)
• Macro expansion errors: fixed error location and body evaluation for non-quasiquoted templates (9abf9aa, ceecb71)
• Direct param unquotes: no longer eval'd at compile time in macro engine (9b4deab)
• False error for unsupported codegen calls: no longer spurious errors (add7c46)
• Fixed an REPL inline help overflow (inline help occasionally didn't show the proper help section) (f77d06c)

Performance

• Fused value-and-grad IREE dispatch (single IREE dispatch instead of separate forward/backward calls)
• Dot-general optimization (reshape + matmul2D + reshape instead of generic contraction)
• Backward pass optimization (simplify + CSE + double transpose elimination)
• Forward-pass binding reuse in backward to avoid recomputing values already available (ad43163)
• Fixes cache misses for closures capturing scalars (45697e5)
• Scalar constant extraction: singleton tensors extracted as scalars in codegen (5475c2f)
• Apple Accelerate enabled for ndarray on macOS (47c682f, 5c80080)

v2.0.0

Complete rewrite in Rust, with no Python in the execution path. The language semantics remain unchanged: all V1 code runs in V2.

• New architecture: Sheaf source compiles directly to StableHLO MLIR, IREE runtime statically linked and called through FFI.
• Transparent JIT compilation: pure functions compile automatically on first call, with content-hash caching in __sheaf__
• Automatic differentiation via value-and-grad
• DeviceBuffer: compiled functions pass tensors between IREE calls without host round-trips
• Multiple dtype support: f32 (default), bf16, i32 via cast or literal annotation

Full Changelog: v1.2.0...v2.0.0

v2.0.0-rc2

Full Changelog: https://github.com/sheaf-lang/sheaf/commits/v2.0.0-rc2

v2.0.0-rc1

Full Changelog: https://github.com/sheaf-lang/sheaf/commits/v2.0.0-rc1

v1.2.0

• Sheaf programs are now mostly independent from Python, most missing primitives for imperative control have been added.
• I/O module: (io "load" ...) / (io "save" ...) with safetensors and JSON. Entropy source (io "entropy")
• Support f-strings: (print "loss={:.4f}" loss)
• Support string escape sequences: \n, \t, \", \\
• New primitives: filter, find, index-of, argmax, argmin, arange, eye, index-update, int, float, sort, chars, rms-norm, do, while
• Error messages: suggestions for common mistakes (def -> defn, lambda -> fn, import -> use), paren balancer with culprit detection
• REPL has --trace and --guard modes for standalone tracing and debugging
• All examples are now standalone and do not require Python

v1.1.0

• Syntax cleanup: quoted arrays ('[]) are now the canonical way to distinguish lists from tensors. Legacy list form is deprecated.
• More syntax purity: also deprecate lambda (alias for fn) and dict
• Protection for special forms (fn, let, get...)
• Many bugfixes in the compiler

v1.0.0

First stable release (jan 13th 2026)