//! Host-fn import registration + lookup.

//!

//! Each entry in the rpc `HostFnSpec` registry gets wired up here:

//! the wasm import is declared with the spec's param/result types

//! (collapsed to abstract heap-types for GC-ref kinds), and a

//! lookup-table entry records the function index plus the original

//! `WasmType` signature for the compiler's call-site emit.

use super::{CompileContext, HostFnEntry};

use crate::error::Result;

use crate::host_fn::HostFnSpec;

use wasm_encoder::ValType;

impl CompileContext {

        // Args ride the wasm function signature directly. Each declared

        // param type maps to its abstract `WasmTy::valtype()` (`(ref null

        // struct)` for Commodity / Ratio / Pair / EntityRef, `(ref null

        // array)` for StringRef, primitive types unchanged); host fn body

        // reads them as closure args. The earlier capture-queue path

        // retired in P4 A6.b.

        // Result signature is driven by `spec.result` alone. Host fns

        // returning typed GC refs (Ratio / Commodity / StringRef / Pair)

        // report their wasm signature via `WasmTy::valtype()` as the

        // abstract heap type (`(ref null struct)` / `(ref null array)`)

        // — the import declaration matches, and the guest follows the

        // call with a `ref.cast` to recover the concrete type. See

        // `host_import_return_type` for the mapping.

        );

}