link May 23 Meeting Notes

(by Erik Arvidsson)

John Neumann (JN), Allen Wirfs-Brock (AWB), Eric Ferraiuolo (EF), Erik Arvidsson (EA), Luke Hoban (LH), Doug Crockford (DC), Yehuda Katz (YK), Sam Tobin-Hochstadt (STH), Alex Russell (AR), Dave Herman (DH) (calling in), Bernd Mathiske (BM), Andreas Rossberg (ARB), Mark Miller (MM), Tom Van Cutsem (TVC), Istvan Sebestyen (IS)

link Promises vs Monads

MM: ...Continuing from yesterday

AR: https://github.com/slightlyoff/Futures/blob/master/Promise.idl

STH: Don't like resolve but not willing to die on this hill.

AR: DOM has a bunch of ad hoc APIs to do promise like things.

YK: Mozilla is also actively working on APIs using promises.

AR: A lot of methods today return void so we can change these to return a promise. This is forward compatible.

AR: then does recursive unwrapping...

link ES6, ES7, ES8... Mark's Strawman Roadmap

LH: The important part is not the features but the process.

AWB: Can things be decoupled?

LH: These kind of structural questions are the important part

MM: Suggests "concurrency" to be the main theme.

AWB: Thought about the event loop. All we need is a processing queue... put things in the front and the back.

DH: Only need to add to the back.

AWB: OK.

STH: The callback is called at some later point.

AR: Don't think we need to specify the order.

STH: If we are going to specify promises etc we need to be able to specify things in detail. We can be loose in ES6 and then come back in ES7 and provide a more tight spec.

DH: We could specify the pending events as a set or something. Not sure if there is a consensus that we want a fast small ES7. Not opposed to a modularized approach.

AR: Are there any browsers that are not shipping stable ES6 features today.

YK: Yes. V8.

AWB: Where we have problem today is that there is a lot of interdependency.

MM: These ("concurrency") are coupled together to the event loop

AWB: We can do it as a separate non 262 spec

DH: Opposed to a separate spec. Introduces versioning confusion.

AWB: Roll up

DH: Think of all the extra overhead.

STH: Big difference with 402 since it was run by different people.

LH: Lack of confidence in new features has been an issue for implementers. Good exceptions were Object.observe and Proxies where the wiki contained a mostly complete spec.

AWB: We need to have wiki proposals be deltas to the spec.

TVC: We could have "stable" wiki pages. These would have complete spec deltas.

DH: Very concerned about over modularizing.

AWB: We need to find a way to work faster and be less monolithic.

DH: Agree. ES6 process has blocked implementation work.

LH: We are not committed to our designs.

STH: We are not resolving issues until we start to spec. We are not getting feedback until engines starts to implement.

EA: The problem is that we didn't start to spec things until very late. We had agreements on features long before there was any spec drafts for them.

YK: More from our champions before we get to concensus.

ARB: Lots of the proposals were very vague.

AWB: The more complete spec you bring to tc39 the better chance you have to reach consensus.

ARB: Lack of early spec leads to lack of early implementations...

AWB: ...which leads to lack of feedback.

LH: Not more work, just doing the work earlier before things pile up too much.

DH: Need to look at the dependency graph. Hold of the work of later feature.

ARB: We need to higher bar before we accept proposals.

MM: What we agreed to 2 years ago was that the features are the one we want to spend work on speccing.

LH: Less features to bite of.

DH: A lot of us have a hard time not getting too engage in too many features.

YK: if we focused more effort on managing the overall complexity instead of getting stuck on a lot of technical discussions (and nit picking).

DH: Object.observe and Proxy moved fast but are fairly isolated features

TVC: Didn't involve syntax.

AWB: With ES6 we had a long backlog.

DH: A language will have smaller and smaller complexity budgets as it grows.

AR: ES future needs events

DH: Since this is Mark's wishlist people will throw in their pet features.

MM: This is the direction I am going to work.

LH: There is a page on the wiki outlining the goals.

LH: Looking for 2 things: Something that would allow earlier implementations. Have not brought proposals (over the last 2 years) because we have been blocked by ES6.

LH: When is the appropriate time to bring new proposals to TC39?

AWB: We are free to do what we want. We can issue 6.1, 6.2 etc or technical reports which would serve as a recommendation.

DH: We cannot exclusively work on ES6.

YK: Time at f2f is the most important. Champions can go off and do what they want.

DH: Suggests adding non ES6 items to the agenda. We will prioritize the non ES6 stuff we can get to given our limited time.

YK: We should reinstate the rule that agenda items needs links to wiki pages.

YK: Spec language is good but examples at the top are a must.

ARB: Add step after proposal. For example "stable" or "spec" which a proposal gets promoted to once there is a spec draft, good enough to start implementing.

DH: Strawman: Anything goes.

YK: Proposals used to mean approved.

DH: 3 sections: strawman, proposal, spec/candidate. Keep strawman. Work on improving as a proposal, and when mature enough promoted to next level.

link May 22 Meeting Notes

(by Erik Arvidsson)

John Neumann (JN), Allen Wirfs-Brock (AWB), Eric Ferraiuolo (EF), Erik Arvidsson (EA), Luke Hoban (LH), Doug Crockford (DC), Yehuda Katz (YK), Brendan Eich (BE), Sam Tobin-Hochstadt (STH), Alex Russell (AR), Dave Herman (DH) (calling in), Bernd Mathiske (BM), Andreas Rossberg (ARB), Mark Miller (MM), Tom Van Cutsem (TVC), Istvan Sebestyen (IS), Jasvir Naga (JNA)

link 4.16 Spec update

http://wiki.ecmascript.org/doku.php?id=harmony:specification_drafts

YK: ToPositiveInteger is needed by JSIDL

AI(YK+AWB): Put an algorithm in the spec that DOM can use so that we get the same behavior in JS and DOM.

6 General implementation experiences

ARB: We started implementing generators but things are pretty smooth.

BE: Doing modules at the moment.

AWB: Bunch of bug fixes in the spec related to classes.

link 4.9 Template Strings (Template Literals)

MM: Suggests status quo.

AR: Objects

MM: Controversy related to tag-less templates. Alternatives include making tag-less templates an error, delayed evaluation (contextually provided)

AR: Econics: naked interpolation is too attractive. Should always have a tag to encourage users to think about which behavior is correct.

YK: I cannot support Alex's proposal.

STH: What would the name of this tag be?

AR: Something that is imported from a module.

STH: Concerned about short names and conflicts.

YK: People will just use 's' without thinking.

YK: People should use HTML templating engines.

DC: Alex's testimony about application developer feedback is relevant.

LH: it sounded like Google engineers were using a template system

EA: Correct.

MM: Does anyone prefer taking out TS if they don't get tag-less TS?

Everyone: Agrees that it is better to require tag than to remove TS from ES6.

AR: Strings are always used later in some context. Communicating the intent

AWB: String concat vs string interpolation have the same issue.

LH: Assumes that maybe only 20% of the uses of TS are susceptible to XSS

MM: Removing tag-less does not reduce XSS because people will just use

s`...`

TS helps people transition to a better world. Once they have have a TS it will be easy to add an html tag at the front as needed.

ST: It will be painful to import String raw and alias that to s.

MM: Maybe put tag-less in appendix? Withdrawn idea because no one likes it.

YK: You should not have use string based APIs.

AR: Willing to abstain but "Y'all are making a big mess"

BM: Half convinced by Alex.

LH: Different code bases will use different tags for normal string interpolation so moving between code bases will be hard to.

AR: That is a good thing. Forces people to think.

MM: Template strings in E.

STH: Lots of contexts where XSS is not an issue.

BM: More ways to XSS is a bad thing.

BE: if people have to import s then the economics change and people will stick to +

link Consensus/Resolution:

• AR and BM sustains.
• Continue with the status quo (tag-less TS is supported)

link JSON

DC: IETF wants to change JSON

MM: The 2 documents should have exactly the same text except for boilerplate.

IS: Should it be done in TC39?

DC: Most of the work will be on the mailing lists

AWB: Who will be the editor?

DC: Hopes they (IETF) will provide an editor.

JN: Should this be fast tracked to ISO?

DC: That makes sense.

JN: How long do you expect this to take?

DC: Has taken a long time to coordinate and get started. 5.1 specs the 2 functions that uses the JSON format.

link 4.10 Modules

STH: Progress since last meeting. Discuss "module naming", "naming standard modules". http://wiki.ecmascript.org/doku.php?id=harmony:modules Wiki is up to date with the current proposal. Spec is "wiki complete".

Jason Orendorff of Mozilla has worked on flushing out semantic issues. Moz is implementing parsing of modules.

STH: Syntax: Made a couple of changes.

A. To support anonymous exports

export default expr;
 
import $ from "jquery";  // imports default anonymous export

If there is no default then the above is an error

import {ajax} from "jquery";
 
import {ajax as A} from "jquery";

to reduce confusion and to make it clear that this is not destructuring.

module fs from "js/fs"

• fs is a module instance object

The following is not valid:

import {...} from fs;  // SyntaxError

Renaming on export:

let foo = 13;
export { foo as bar };
export { foo };

The following is not valid:

export foo;

STH: The only evaluation here is "13". The rest are just bindings that are shared with the outside/module importer.

MM: Bad idea to allow external modules to assign to imports.

DH: Imported bindings are read only to the importer.

AWB: This is new semantics to the language. Is there a list of these new semantics modules introduce?

AWB: Is there a way to get the default export from the instance module obejct.

STH: There will be a well known symbol name to get to it.

AWB: Does module instance objects inherit from Object.prototype.

DH: No. Because we do not want any pollution.

JNA: Is it an error to assign to an imported binding?

import {ajax} from "jquery";
ajax = 14;  // Error

AR: What is the reason for not extending Object.prototype or some other object?

YK: To prevent people from expecting toString to be there (???)

DH: fs.readFile We don't want to statically check this deeply inside an expression.

fs.toString

THS: The plan is to allow the above to be a static error in the future.

DH: To keep things clean.

AWB: Concerned about the dot operator

ARB: Don't want less checking if you do not use import.

DH: Do not want refactoring hazards.

ARB: This only affect the static semantics.

AWB: Can you use square bracket?

STH: Square bracket is dynamic.

AR: This is only a static check that is lost. At runtime there will still be errors.

LH: Concerned about default export. Now people will have to decide which approach to use.

STH: This is already the case in Node.js today.

LH: Today you might get any object, it might be callable with properties.

var fs = require("fs");  // module instance
var glob = require("glob");  // function with properties
var parse = require("parse");  // function
 
module fs from "fs";
import glob from "glob";
import {sync} from "glob";
import parse from "parse";

Lots of discussion...

import {sync} from "glob";

alt

import glob from "glob";
var {sync} = glob;
import {ajax} from "jquery";

LH: Prefers export = and lose static checking when people opt in to single anonymous export.

STH/YK: We already agreed that we want static checking.

LH: Even for new things being built, this is causing a confusion.

AWB: It is unclear when and what you want to export as the default export.

BM: Wants

import default $ from "jquery"

...to ensure that people have to be explicit about what they import.

DH: This is just syntax and we are wasting time "bikeshedding"

AWB: What is the best practice? Is there a single module containing Map, Set & WeakMap or...

YK: WeakMap should be its own import:

import WeakMap from "collections/WeakMap";

BE: We have to pay attention to what Node/AMD do today.

YK: AMD tries to make modules small to reduced byte size of the dependencies.

STH: And now to semantics https://github.com/jorendorff/js-loaders/blob/master/browser-loader.js

Major things that changed. Use options object more consistently. The wiki page is up to date. Need to decide whether the browser loader is in the appendix or if it is in some w3c spec. Want core language semantics to treat the names as strings, not the semantics of these strings. Bulk loading. One HTTP request to load multiple modules. Possible to implement. Create fecth hook. Stores module notations in a side table. In the xhr response, split the result and call the different fulfill hooks.

EF: Sounds like what we do today in YUI loaders. How would you write the HTML?

DH: Initial script tag with configuration. Second script tag as usual. Alt 2 is to have configuration and dynamic module load in the same script block.

<script>
ondemand
</script>
<script src="main.js" async></script>

alt 2

<script>
ondemand
System.require("main.js", function() { .... });
</script>

DH: script[async] today have to use an external src.

STH: Naming and declarations of modules.

ARB: Presenting slides...

AWB: The rate that internal vs external names changes is very different.

STH:

module "m" { ... }
module "n" {
  import x from "m";
  ...// this part is not executed.
}
import x from "m";

STH: Configuration step is mostly about other people's code.

<script>
module "m" { ... }
module "n" {
  import m from "m";
  function f() {
    Loader.eval("import m from 'n'");
  }
}
</script>

m is fixed at compile time

ARB: Not opposed to logical modules. Wants both lexical and logical

DH: Not opposed to lexical modules.

YK: Too late to work out lexical modules for ES6.

ARB: If we wait we will have redundancy.

YK: Want declarative form to be able to prefetch etc.

BE: I want lexical modules (in the future) but logical modules are easier to use.

ARB: Since I don't seem to be able to convince anyone I'm going to drop this

ARB: For the record. Major concern about the global registry becoming the new global object.

link Consensus/Resolution:

• Move along with Dave and Sam's proposal.
• Work on lexical modules for ES7