Spec (eval.sx, primitives.sx):
- Named let: (let loop ((i 0)) body) — self-recursive lambda with TCO
- letrec: mutually recursive local bindings with closure patching
- dynamic-wind: entry/exit guards with wind stack for future continuations
- eq?/eqv?/equal?: identity, atom-value, and deep structural equality
Implementation (evaluator.py, async_eval.py, primitives.py):
- Both sync and async evaluators implement all four forms
- 33 new tests covering all forms including TCO at 10k depth
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Bootstrap shift/reset to both Python and JS targets. The implementation
uses exception-based capture with re-evaluation: reset wraps in try/catch
for ShiftSignal, shift raises to the nearest reset, and continuation
invocation pushes a resume value and re-evaluates the body.
- Add Continuation type and _ShiftSignal to shared/sx/types.py
- Add sf_reset/sf_shift to hand-written evaluator.py
- Add async versions to async_eval.py
- Add shift/reset dispatch to eval.sx spec
- Bootstrap to Python: FIXUPS_PY with sf_reset/sf_shift, regenerate sx_ref.py
- Bootstrap to JS: Continuation/ShiftSignal types, sfReset/sfShift in fixups
- Add continuation? primitive to both bootstrappers and primitives.sx
- Allow callables (including Continuation) in hand-written HO map
- 44 unit tests (22 per evaluator) covering: passthrough, abort, invoke,
double invoke, predicate, stored continuation, nested reset, practical patterns
- Update continuations essay to reflect implemented status with examples
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
HO forms (map, filter, reduce, etc.) now use call-fn which dispatches
Lambda → call-lambda, native callable → apply, else → clear EvalError.
Previously call-lambda crashed with AttributeError on native functions.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Previously defhandler routed to sf-define which tried to evaluate
(&key ...) params as expressions. Now each form has its own spec
with parse-key-params and platform constructors.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Two fixes for sx-browser.js (spec-compiled) vs sx.js (hand-written):
1. CSS meta tag mismatch: initCssTracking read meta[name="sx-css-hash"]
but the page template uses meta[name="sx-css-classes"]. This left
_cssHash empty, causing the server to send ALL CSS as "new" on every
navigation, appending duplicate rules that broke Tailwind responsive
ordering (e.g. menu bar layout).
2. Stale verb info after morph: execute-request used captured verbInfo
from bind time. After morph updated element attributes (e.g. during
OOB nav swap), click handlers still fired with old URLs. Now re-reads
verb info from the element first, matching sx.js behavior.
Also includes: render-expression dispatch in eval.sx, NIL guard for
preload cache in bootstrap_js.py, and helpers.py switched to
sx-browser.js.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Split monolithic render.sx into core (tag registries, shared utils) plus
four adapter .sx files: adapter-html (server HTML strings), adapter-sx
(SX wire format), adapter-dom (browser DOM nodes), and engine (SxEngine
triggers, morphing, swaps). All adapters written in s-expressions with
platform interface declarations for JS bridge functions.
Bootstrap compiler now accepts --adapters flag to emit targeted builds:
-a html → server-only (1108 lines)
-a dom,engine → browser-only (1634 lines)
-a html,sx → server with SX wire (1169 lines)
(default) → all adapters (1800 lines)
Fixes: keyword arg i-counter desync in reduce across all adapters,
render-aware special forms (let/if/when/cond/map) in HTML adapter,
component children double-escaping, ~prefixed macro dispatch.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Meta-circular evaluator: the SX language specifying its own semantics.
A thin bootstrap compiler per target (JS, Python, Rust) reads these
.sx files and emits a native evaluator.
Files:
- eval.sx: Core evaluator — type dispatch, special forms, TCO trampoline,
lambda/component/macro invocation, higher-order forms
- primitives.sx: Declarative specification of ~80 built-in pure functions
- render.sx: Three rendering modes (DOM, HTML string, SX wire format)
- parser.sx: Tokenizer, parser, and serializer specification
Platform-specific concerns (DOM ops, async I/O, HTML emission) are
declared as interfaces that each target implements.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
