nordisk/knut

knut-bifrost-wasm-guest — crate card

Reverse-engineered (from source — verify, don't trust the name)

• One-line pitch: A real wasm32-unknown-unknown guest module for knut-bifrost's WasmTransform host — Arrow IPC stream in, Arrow IPC stream out — proving arrow-on-wasm and serving as a template for user guests.
• Does: Exposes the guest ABI the host expects: alloc(len) -> i32 (reserve linear-memory bytes via a Vec-leak for the host to write the input IPC into) and transform(ptr, len) -> i64 (read the Arrow-IPC stream, keep only rows where _gar_id is even, write the survivors back as an IPC stream in a leaked buffer, return (out_ptr << 32) | out_len). On any error it writes an empty-but-valid IPC stream (schema only). #![no_std] + extern crate alloc.
• Key deps: arrow-array/arrow-schema/arrow-ipc/arrow-select pinned to arrow 59 (to match the host's IPC format), all default-features = false for a lean wasm footprint. No workspace deps.
• Shape: cdylib lib only; tiny (single lib.rs). Release profile: opt-level="z", lto, panic="abort". Not a workspace member — its own one-package [workspace], excluded from the native knut root so it only builds for wasm32.
• Observed role in the workspace: Test/demo fixture and template for knut-bifrost's wasm feature (src/wasm.rs host, wasmi interpreter). Built explicitly with cargo build --target wasm32-unknown-unknown --release; artifact knut_bifrost_wasm_guest.wasm is consumed by bifrost's wasm tests.

Fill in (one line each — only the human knows these)

• Primary consumer(s):
• Why it exists (vs the obvious alternative):
• Hard constraint (airgap / no-C-deps / no-FFI / pure-Rust / etc.):
• Release cadence & independence (rides a parent? own repo someday?):
• Status (production / prototype / experimental / stubbed):
• Must-NOT-change invariant:
• Biggest known gap or TODO:
• Anything a newcomer would get wrong about it: