1/**
2 * WASI is enabled through asconfig.json in post 0.20.x versions of AssemblyScript.
3 * The module, @assemblyscript/wasi-shim is required to enable a WASI environment.
4 *
5 * This demo is meant to showcase some abilities of WASI utilized through the AssemblyScript language.
6 * It uses the latest version of AssemblyScript and will not work in older (<0.20.x) versions.
7**/
8
9// Import module that allows colors in the console as long as supported by WASI.
10import { rainbow } from "as-rainbow/assembly";
11
12// Call console.log which is overridden to use WASI syscalls by @assemblyscript/wasi-shim.
13console.log(rainbow.blue(rainbow.boldMk("Hello from WasmTime WASI through AssemblyScript!")));
14
15console.log(rainbow.boldMk("Press ctrl+c to exit this demo at any time."));
16
17// Get the current time and print it.
18console.log("\nWASI can read the system time and display it with the AssemblyScript Date API");
19console.log(rainbow.boldMk("The current time is: ") + rainbow.italicMk(new Date(Date.now()).toString()));
20
21// Read user input from process.stdin (API provided by AssemblyScript Wasi-Shim and WasmTime WASI API).
22
23// Create a buffer to hold up to 100 characters of user input.
24const buffer = new ArrayBuffer(100);
25console.log("\nWASI can read user input from stdin. Write any word and return");
26
27// Read data from stdin and write to buffer.
28process.stdin.read(buffer);
29
30// Print text and decode the buffer with String.UTF8.decode
31console.log(rainbow.red("You said: " + String.UTF8.decode(buffer)))
32
33waitForUserEnter("\nPlease press return to continue");
34
35// Demonstrate the retrieval of cryptographically-safe random numbers through WASI.
36console.log("WASI can fetch cryptographically-safe random numbers from the runtime\nSeries of random numbers:");
37
38for (let i = 0; i < 5; i++) {
39    console.log(Math.random().toString());
40}
41
42// End
43console.log(rainbow.red("\nThat's all! :D"));
44
45function waitForUserEnter(text: string): void {
46    console.log(rainbow.italicMk(text));
47    const buf = new ArrayBuffer(1);
48    process.stdin.read(buf);
49    return;
50}