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/// This example demonstrates how to import a function from the host environment and call it from a WebAssembly module.
import WasmKit
import WAT
@main
struct Example {
static func main() throws {
// Convert a WAT file to a Wasm binary, then parse it.
let module = try parseWasm(
bytes: try wat2wasm(
"""
(module
(import "printer" "print_i32" (func $print_i32 (param i32)))
(func (export "print_add") (param $x i32) (param $y i32)
(call $print_i32 (i32.add (local.get $x) (local.get $y)))
)
)
"""
)
)
// Create engine and store
let engine = Engine()
let store = Store(engine: engine)
// Instantiate a parsed module with importing a host function
let instance = try module.instantiate(
store: store,
// Import a host function that prints an i32 value.
imports: [
"printer": [
"print_i32": Function(store: store, parameters: [.i32]) { _, args in
// This function is called from "print_add" in the WebAssembly module.
print(args[0])
return []
}
]
]
)
// Invoke the exported function "print_add"
let printAdd = instance.exports[function: "print_add"]!
try printAdd([.i32(42), .i32(3)])
}
}
|
