Start roadmap document.

README.md

@@ -59,7 +59,7 @@ No docs yet. For some of the public API see: [deno.d.ts](https://github.com/ry/d
 
 And examples are around here: [testdata/004_set_timeout.ts](https://github.com/ry/deno/blob/master/testdata/004_set_timeout.ts).
 
-Roadmap is [here](https://github.com/ry/deno/blob/master/TODO.txt).
+Roadmap is [here](https://github.com/ry/deno/blob/master/Roadmap.md).
 
 Also see this presentation: http:https://tinyclouds.org/jsconf2018.pdf
 

Roadmap.md

@@ -0,0 +1,129 @@
+# Deno Roadmap
+
+API and Feature requests should be submitted as PRs to this document.
+
+## Milestone 1: Rust rewrite / V8 snapshot
+
+ETA: July 2018.
+
+Go is a garbage collected language and we are worried that combining it with
+V8's GC will lead to difficult contention problems down the road. This work
+is being done in the deno2 sub-directory.
+
+The V8Worker2 binding/concept is being ported to a new C++ library called
+libdeno. libdeno will include the entire JS runtime as a V8 snapshot. It still
+follows the message passing paradigm. Rust will be bound to this library to
+implement the privileged part of Deno. See deno2/README.md for more details.
+
+V8 Snapshots allow Deno to avoid recompiling the TypeScript compiler at
+startup. This is already working.
+
+When the rewrite is at feature parity with the Go prototype, we will release
+binaries for people to try.
+
+
+## TypeScript API.
+
+
+There are three layers of API to consider:
+* L1: the low-level message passing API exported by libdeno (L1),
+* L2: the protobuf messages used internally (L2),
+* L3: the final "deno" namespace exported to users (L3).
+
+### L1
+
+https://github.com/ry/deno/blob/master/deno2/js/deno.d.ts
+
+```
+pub(channel: string, msg: ArrayBuffer): null | ArrayBuffer;
+```
+The only interface to make calls outside of V8. You can send an ArrayBuffer and
+synchronously receive an ArrayBuffer back. The channel parameter specifies the
+purpose of the message.
+
+```
+type MessageCallback = (channel: string, msg: ArrayBuffer) => void;
+function sub(cb: MessageCallback): void;
+```
+A way to set a callback to receive messages asynchronously from the privileged
+side. Note that there is no way to respond to incoming async messages.
+`sub()` is not strictly necessary to implement deno. All communication could
+be done through `pub` if there was a message to poll the event loop. For this
+reason we should consider removing `sub`.
+
+```
+function print(x: string): void;
+```
+A way to print to stdout. Although this could be easily implemented thru `pub()`
+this is an important debugging tool to avoid intermediate infrastructure.
+
+
+### L2
+
+https://github.com/ry/deno/blob/master/msg.proto
+
+### L3
+
+With in Deno this is the high-level user facing API. However, the intention
+is to expose functionality as simply as possible. There should be little or
+no "ergonomics" APIs. (For example, `deno.readFileSync` only deals with
+ArrayBuffers and does not have an encoding parameter to return strings.)
+The intention is to make very easy to extend and link in external modules
+which can then add this functionality.
+
+Deno does not aim to be API compatible with Node in any respect. Deno will
+export a single flat namespace "deno" under which all core functions are
+defined. We leave it up to users to wrap Deno's namespace to provide some
+compatibility with Node.
+
+*Top-level await*: This will be put off until at least deno2 Milestone1 is
+complete. One of the major problems is that top-level await calls are not
+syntactically valid TypeScript.
+
+Functions exported under Deno namespace:
+```ts
+deno.readFileSync(filename: string): ArrayBuffer;
+deno.writeFileSync(filename: string, data: Uint8Array, perm: number): void;
+```
+
+Timers:
+```ts
+setTimeout(cb: TimerCallback, delay: number, ...args: any[]): number;
+setInterval(cb: TimerCallbac, duration: number, ...args: any[]): number;
+clearTimeout(timerId: number);
+clearInterval(timerId: number);
+```
+
+Console:
+```ts
+declare var console: {
+ log(...args: any[]): void;
+ error(...args: any[]): void;
+ assert(assertion: boolean, ...msg: any[]): void;
+}
+```
+
+URL:
+```ts
+URL(url: string, base?: string): URL;
+```
+
+Text encoding:
+```ts
+declare var TextEncoder: {
+ new (utfLabel?: string, options?: TextEncoderOptions): TextEncoder;
+ (utfLabel?: string, options?: TextEncoderOptions): TextEncoder;
+ encoding: string;
+};
+
+declare var TextDecoder: {
+ new (label?: string, options?: TextDecoderOptions): TextDecoder;
+ (label?: string, options?: TextDecoderOptions): TextDecoder;
+ encoding: string;
+};
+```
+
+Fetch API:
+```ts
+fetch(input?: Request | string, init?: RequestInit): Promise<Response>;
+```