Core VM changes:
- Add VmClosure value variant — inner closures created by OP_CLOSURE are
first-class VM values, not NativeFn wrappers around call_closure
- Convert `run` from recursive to while-loop — zero OCaml stack growth,
true TCO for VmClosure tail calls
- vm_call handles VmClosure by pushing frame on current VM (no new VM
allocation per call)
- Forward ref _vm_call_closure_ref for cross-boundary calls (CEK/primitives)
Compiler (spec/compiler.sx):
- Define hoisting in compile-begin: pre-allocate local slots for all
define forms before compiling any values. Fixes forward references
between inner functions (e.g. read-expr referencing skip-ws in sx-parse)
- scope-define-local made idempotent (skip if slot already exists)
Server (sx_server.ml):
- JIT fail-once sentinel: mark l_compiled as failed after first VM runtime
error. Eliminates thousands of retry attempts per page render.
- HTML tag bindings: register all HTML tags as pass-through NativeFns so
eval-expr can handle (div ...) etc. in island component bodies.
- Log VM FAIL errors with function name before disabling JIT.
SSR fixes:
- adapter-html.sx letrec handler: evaluate bindings in proper letrec scope
(pre-bind nil, then evaluate), render body with render-to-html instead of
eval-expr. Fixes island SSR for components using letrec.
- Add `init` primitive to OCaml kernel (all-but-last of list).
- VmClosure handling in sx_runtime.ml sx_call dispatch.
Tests: 971/971 OCaml (+19 new), 0 failures.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>