feat: add some utilities

src/program/Eval.ts

@@ -0,0 +1,17 @@
+import type { SimpleStream } from '../utils/SimpleStream'
+import { Program } from './Program'
+
+export class Eval extends Program {
+    async Exec(_: SimpleStream<string>, stdout: SimpleStream<string>, args: string[]): Promise<number> {
+        const javascript = args.slice(1).join(' ')
+
+        try {
+            eval(javascript)
+        } catch (e) {
+            stdout.emit(`${String(e)}\n`)
+            return 1
+        }
+
+        return 0
+    }
+}