Update examples to use WAT module

Author: kateinoigakukun

Examples/Package.swift

@@ -0,0 +1,26 @@
+// swift-tools-version:5.8
+
+import PackageDescription
+
+let package = Package(
+    name: "Examples",
+    platforms: [.macOS(.v10_13), .iOS(.v12)],
+    dependencies: [
+        .package(path: "../")
+    ],
+    targets: [
+        .executableTarget(name: "Factorial", dependencies: [
+            "WasmKit",
+            .product(name: "WAT", package: "WasmKit")
+        ]),
+        .executableTarget(name: "PrintAdd", dependencies: [
+            "WasmKit",
+            .product(name: "WAT", package: "WasmKit")
+        ]),
+        .executableTarget(name: "WASI-Hello", dependencies: [
+            "WasmKit",
+            .product(name: "WasmKitWASI", package: "WasmKit"),
+            .product(name: "WAT", package: "WasmKit"),
+        ]),
+    ]
+)

Examples/README.md

@@ -0,0 +1,3 @@
+# Examples
+
+This directory contains a number of examples that demonstrate how to use the `WasmKit` library.

Examples/Sources/Factorial/Factorial.swift

@@ -0,0 +1,18 @@
+/// This example demonstrates how to call a function exported by a WebAssembly module.
+
+import WasmKit
+import WAT
+import Foundation
+
+// Convert a WAT file to a Wasm binary, then parse it.
+let module = try parseWasm(
+    bytes: try wat2wasm(String(contentsOfFile: "wasm/factorial.wat"))
+)
+
+// Create a module instance from the parsed module.
+let runtime = Runtime()
+let instance = try runtime.instantiate(module: module)
+let input: UInt64 = 5
+// Invoke the exported function "fac" with a single argument.
+let result = try runtime.invoke(instance, function: "fac", with: [.i64(input)])
+print("fac(\(input)) = \(result[0].i64)")

Examples/Sources/PrintAdd/PrintAdd.swift

@@ -0,0 +1,33 @@
+/// This example demonstrates how to import a function from the host environment and call it from a WebAssembly module.
+
+import WasmKit
+import WAT
+import Foundation
+
+// 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)))
+          )
+        )
+        """
+    )
+)
+
+// Define a host function that prints an i32 value.
+let hostPrint = HostFunction(type: FunctionType(parameters: [.i32])) { _, args in
+    // This function is called from "print_add" in the WebAssembly module.
+    print(args[0])
+    return []
+}
+// Create a runtime importing the host function.
+let runtime = Runtime(hostModules: [
+    "printer": HostModule(functions: ["print_i32": hostPrint])
+])
+let instance = try runtime.instantiate(module: module)
+// Invoke the exported function "print_add"
+_ = try runtime.invoke(instance, function: "print_add", with: [.i32(42), .i32(3)])

Examples/Sources/WASI-Hello/Hello.swift

@@ -0,0 +1,20 @@
+// This example demonstrates WASI support in WasmKit.
+
+import WasmKit
+import WasmKitWASI
+import WAT
+import Foundation
+
+// Parse a WASI-compliant WebAssembly module from a file.
+let module = try parseWasm(filePath: "wasm/hello.wasm")
+
+// Create a WASI instance forwarding to the host environment.
+let wasi = try WASIBridgeToHost()
+// Create a runtime with WASI host modules.
+let runtime = Runtime(hostModules: wasi.hostModules)
+let instance = try runtime.instantiate(module: module)
+
+// Start the WASI command-line application.
+let exitCode = try wasi.start(instance, runtime: runtime)
+// Exit the Swift program with the WASI exit code.
+exit(Int32(exitCode))

Examples/wasm/factorial.wat

@@ -1,3 +1,4 @@
+(module
   (func $fac (export "fac") (param i64) (result i64)
     (if (result i64) (i64.eqz (local.get 0))
       (then (i64.const 1))
@@ -9,3 +10,4 @@
       )
     )
   )
+)