golang
Go programmmig language
The Go programming language is an open source project to make programmers more productive.
Go is expressive, concise, clean, and efficient. Its concurrency mechanisms make it easy to write programs that get the most out of multicore and networked machines, while its novel type system enables flexible and modular program construction. Go compiles quickly to machine code yet has the convenience of garbage collection and the power of run-time reflection. It's a fast, statically typed, compiled language that feels like a dynamically typed, interpreted language.
Hello world
List of GOOS and GOARCH
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1 go tool dist list
Some elements of the list
android/386 android/amd64 android/arm android/arm64 darwin/386 darwin/amd64 darwin/arm darwin/arm64 freebsd/386 freebsd/amd64 freebsd/arm js/wasm linux/386 linux/amd64 linux/arm linux/arm64 netbsd/386 netbsd/amd64 netbsd/arm openbsd/386 openbsd/amd64 openbsd/arm windows/386 windows/amd64
WebAssembly
- On debian buster
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1 sudo apt install golang # go version go1.11.6 linux/amd64
2 sudo apt install golang-src
3 mkdir ~/wasmgotest
build.sh
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1 go build -o main main.go
2 GOOS=js GOARCH=wasm go build -o main.wasm main.go
index.html
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1 <html>
2 <head>
3 <meta charset="utf-8"/>
4 <script src="wasm_exec.js"></script>
5 <script>
6 const go = new Go();
7 WebAssembly.instantiateStreaming(fetch("main.wasm"), go.importObject).then((result) => {
8 go.run(result.instance);
9 });
10 </script>
11 </head>
12 <body>
13 <h1 id="datetimeHeading">5555</h1>
14 <canvas id="myCanvas" width="200" height="100" style="border:1px solid #000000;">
15 </canvas>
16 </body>
17 </html>
main.go
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1 package main
2
3 //import "fmt"
4 import "time"
5 import "syscall/js"
6
7 func showTime(){
8 for x := 0; ; x++ { // infinite loop
9 currentTime := time.Now()
10 // console.log in the browser
11 //fmt.Printf("Hello, WebAssembly %s ! \n" , currentTime.String() )
12 document := js.Global().Get("document")
13 document.Call("getElementById", "datetimeHeading").Set("innerHTML", currentTime.String())
14 //document.getElementById("datetimeHeading").innerHTML="aaa"
15 time.Sleep( 2 * time.Second )
16 }
17 }
18
19 func main() {
20 go showTime() // go routine executes the called function as a lightweight thread
21
22 document := js.Global().Get("document")
23 c := document.Call("getElementById","myCanvas")
24 ctx := c.Call("getContext","2d")
25 ctx.Call("beginPath")
26 ctx.Call("arc","95", "50", "40", "0", "6.283")
27 ctx.Call("stroke");
28
29 time.Sleep(24*time.Hour)
30 }
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1 cp /usr/share/go-1.11/misc/wasm/wasm_exec.js .
Check on the browser file:///home/vitor/wasmgotest/index.html