(index-of s needle from?) returns first index of needle in s, or -1.
Optional start offset. Specced in primitives.sx, implemented in both
hand-written primitives.py and bootstrapper templates, rebootstrapped.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Both bootstrappers (JS + Python) now gate shift/reset behind --extensions
continuations flag. Without it, using reset/shift errors at runtime.
- JS bootstrapper: extracted Continuation/ShiftSignal types, sfReset/sfShift,
continuation? primitive, and typeOf handling into CONTINUATIONS_JS constant.
Extension wraps evalList, aserSpecial, and typeOf post-transpilation.
- Python bootstrapper: added special-forms.sx validation cross-check against
eval.sx dispatch, warns on mismatches.
- Added shared/sx/ref/special-forms.sx: 36 declarative form specs with syntax,
docs, tail-position, and examples. Used by bootstrappers for validation.
- Added ellipsis (...) support to both parser.py and parser.sx spec.
- Updated continuations essay to reflect optional extension architecture.
- Updated specs page and nav with special-forms.sx entry.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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>
The JS parser transpiled from parser.sx used tail-recursive functions
(readStrLoop, skipWs, readListLoop, etc.) which overflow the stack on
large inputs — the bootstrapper page highlights 100KB of Python and
143KB of JavaScript, producing 7620 spans in a 907KB response.
The bootstrapper now detects zero-arg self-tail-recursive functions and
emits them as while(true) loops with continue instead of recursive
calls. Tested with 150K char strings and 8000 sibling elements.
Also enables SX_USE_REF=1 in dev via x-dev-env anchor.
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>
engine.sx now contains only pure logic: parsing, morph, swap, headers,
retry, target resolution, etc. orchestration.sx contains the browser
wiring: request execution, trigger binding, SSE, boost, post-swap
lifecycle, and init. Dependency is one-way: orchestration → engine.
Bootstrap compiler gains "orchestration" as a separate adapter with
deps on engine+dom. Engine-only builds get morph/swap without the
full browser runtime.
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>
bootstrap_js.py reads the reference .sx specification (eval.sx, render.sx)
and transpiles the defined evaluator functions into standalone JavaScript.
The output sx-ref.js is a fully functional SX evaluator bootstrapped from
the s-expression spec, comparable against the hand-written sx.js.
Key features:
- JSEmitter class transpiles SX AST → JS (fn→function, let→IIFE, cond→ternary, etc.)
- Platform interface (types, env ops, primitives) implemented as native JS
- Post-transpilation fixup wraps callLambda to handle both Lambda objects and primitives
- 93/93 tests passing: arithmetic, strings, control flow, closures, HO forms,
components, macros, threading, dict ops, predicates
Fixed during development:
- Bool before int isinstance check (Python bool is subclass of int)
- SX NIL sentinel detection (not Python None)
- Cond style detection (determine Scheme vs Clojure once, not per-pair)
- Predicate null safety (x != null instead of x && to avoid 0-as-falsy in SX)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
