Brings the WAT tier to parity with c-emcc and pyodide for streaming
output during evalLisp. Previously the asm tier buffered everything
in the 0x10000 output region and the JS loader only read the bytes
AFTER lumbda_eval returned — fox saw the bend demo's pre-call
displays sit invisible for 18 s and then appear all at once.
WAT-side changes:
- New env.emit_chunk(ptr, len) import. Host function forwards the
slice to the current onChunk callback so the worker can postMessage
a chunk to the playground panel as work happens.
- New $flush_start global tracks the offset (relative to 0x10000)
where the next emit_chunk slice begins. Reset to 0 at the top
of lumbda_eval alongside $output_len so successive evals don't
re-emit stale bytes.
- $out_char now checks for newline (i32.const 10) after the store.
A newline emits the slice [flush_start, output_len) and advances
flush_start to the end. Every display call ends up flushing on
its trailing newline; per-char displays without a newline get
buffered until the next newline or the eval-end trailing flush.
- $lumbda_eval ends with a trailing-flush guard so any non-newline-
terminated content (e.g. print_value's final repr) reaches the
stream instead of only landing through the final lumbda_output_*
read.
JS loader:
- importObj.env.emit_chunk decodes the slice from wasm memory and
forwards to refs.currentOnChunk.
- evalLisp(src, onChunk) parameter; sets/clears currentOnChunk
around the lumbda_eval call. Same shape as c-emcc + pyodide.
Tests: every node test that instantiates the asm wasm directly now
declares a stub emit_chunk() {} alongside its bend_call stub —
unit, integration, functional-cross, parity-cross-tier. Node test
suite passes 23/23 unit; parity probe times out in its full sweep
under our 30s ceiling so it gets run separately.
Quick smoke: (display "line 1") (newline) (display "line 2") (newline)
(display "line 3") emits three chunks via onChunk — "line 1\n",
"line 2\n", "line 3" — and lumbda_output_* still has the full
"line 1\nline 2\nline 3" as before.
russell@unturf.com
d14c0eb5e4