arduino 添加 wat 例子

_examples/arduino-wat/Makefile

+# 版权 @2022 凹语言 作者。保留所有权利。
+
+default:
+	go run ../../main.go -target=arduino hello.wat
+
+clean:
+	-rm *.wasm

_examples/arduino-wat/hello.wat

+;; 版权 @2022 凹语言 作者。保留所有权利。
+
+(module $wa-arduino-hello
+	(import "arduino" "getPinLED" (func $getPinLED (result i32)))
+	(import "arduino" "pinMode" (func $pinMode (param $pin i32) (param $mode i32)))
+	(import "arduino" "digitalWrite" (func $digitalWrite (param $pin i32) (param $value i32)))
+	(import "arduino" "delay" (func $delay (param $ms i32)))
+
+	(memory (;0;) 1)
+	(export "memory" (memory 0))
+	(export "_start" (func $main))
+
+	(func $main (local $tmp i32)
+		;; var LED i32 = getPinLED()
+		;; &LED == 1024
+		i32.const 1024
+		call $getPinLED
+		local.tee $tmp
+		i32.store
+
+		;; pinMode(LED, 1)
+		local.get $tmp
+		i32.const 1
+		call $pinMode
+
+		;; for {}
+		loop $label0 ;; label = @1
+			;; digitalWrite(LED, 1)
+			i32.const 1024
+			i32.load
+			i32.const 1
+			call $digitalWrite
+
+			;; delay(100)
+			i32.const 100
+			call $delay
+
+			;; digitalWrite(LED, 0)
+			i32.const 1024
+			i32.load
+			i32.const 0
+			call $digitalWrite
+
+			;; delay(900)
+			i32.const 900
+			call $delay
+
+			;; continue
+			br $label0 (;@1;)
+		end
+
+		;; panic("unreachable")
+		unreachable
+	)
+)