Add a "donkey" worker that execs or evaluates all the things (#2210)

* WIP

* Add a "donkey" worker that execs or evaluates all the things

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

core/src/plugins/donkey.js

@@ -0,0 +1,64 @@
+import { assign, dedent } from "polyscript/exports";
+
+const invoke = (name, args) => `${name}(code, ${args.join(", ")})`;
+
+export default (options = {}) => {
+    const type = options.type || "py";
+    const args = options.persistent
+        ? ["globals()", "__locals__"]
+        : ["{}", "{}"];
+    const src = URL.createObjectURL(
+        new Blob([
+            dedent(`
+                from pyscript import sync, config
+                __message__ = lambda e,v: f"\x1b[31m\x1b[1m{e.__name__}\x1b[0m: {v}"
+                __locals__ = {}
+                if config["type"] == "py":
+                    import sys
+                    def __error__(_):
+                    info = sys.exc_info()
+                    return __message__(info[0], info[1])
+                else:
+                    __error__ = lambda e: __message__(e.__class__, e.value)
+                def execute(code):
+                    try: return ${invoke("exec", args)};
+                    except Exception as e: print(__error__(e));
+                def evaluate(code):
+                    try: return ${invoke("eval", args)};
+                    except Exception as e: print(__error__(e));
+                sync.execute = execute
+                sync.evaluate = evaluate
+            `),
+        ]),
+    );
+
+    const script = assign(document.createElement("script"), { type, src });
+
+    script.toggleAttribute("worker", true);
+    script.toggleAttribute("terminal", true);
+    if (options.terminal) script.setAttribute("target", options.terminal);
+    if (options.config)
+        script.setAttribute("config", JSON.stringify(options.config));
+
+    return new Promise((resolve) => {
+        script.addEventListener(`${type}:done`, (event) => {
+            event.stopPropagation();
+            URL.revokeObjectURL(src);
+            const { xworker, process, terminal } = script;
+            const { execute, evaluate } = xworker.sync;
+            script.remove();
+            resolve({
+                process,
+                execute: (code) => execute(dedent(code)),
+                evaluate: (code) => evaluate(dedent(code)),
+                clear: () => terminal.clear(),
+                reset: () => terminal.reset(),
+                kill: () => {
+                    xworker.terminate();
+                    terminal.dispose();
+                },
+            });
+        });
+        document.body.append(script);
+    });
+};