Add ->* and yield

[vendethiel]

"wip"

Adds a basic version of generators. Tests courtesy of @alubbe.

What's (could be) missing :

• yield from
• tests for an edge case like ~~>*
• disable class => ->* (currently has an error, fixed on my local repo) (also for !->* if we go the hushed route)

Questions :

• Is this syntax okay ? (same for function)
• Should these be hushed by default ? (they're here)

[vendethiel]

(fixed in my local repo)

[hmaurer]

🍰

[wryk]

🍰 WONDERFUL DAY

[askucher]

Well done!

On Fri, Jan 31, 2014 at 12:19 AM, Mathieu Gallé-Tessonneau <
notifications@github.com> wrote:

[image: 🍰] WONDERFUL DAY

Reply to this email directly or view it on GitHubhttps://github.com//pull/462#issuecomment-33740649
.

[vendethiel]

I'll try to get travis setup correctly tomorrow

[gkz]

Awesome! Thanks for your work :)

The syntax looks good.
And yes, they should be hushed by default.

Once this gets merged in I'll look into releasing 1.3.

[vendethiel]

Mostly ready. Needs a special setting for travis -- @gkz do you know how ?

Didn't add function* because of how it's currently parsed.

[vendethiel]

@gkz There doesn't seem to be a way for travis to run a certain command only on a certain platform (that I've found). Should be okay other than that.

[duralog]

hmm, you're right, which is why I want to think about it more. I don't want to remove functionality from the generators, just to make them easier on the eyes for basic patterns. I'll have a clearer idea in a few days, as I'm still getting used to to new concepts.

---

I think, if you put engine node: ">= 0.11.3" it will run the tests on node with harmony (like so: https://github.com/cojs/archan/blob/master/Makefile), but, I think npm will give you a warning if you try to install on 0.10.x so that's not optimal.
instead, I think the solution to that is to add all engines to travis:

 node_js:
   - "0.4"
   - "0.6"
   - "0.8"
   - "0.10"
   - "0.11"

and then in the test script just do a conditional which checks the node version and if it's 0.11.x run the harmony tests as well. I recommend separating these tests out into a separate file and spawning a node process with --harmony-generators from inside the test script.

I'm pretty sure I can get it working. do you want me to make a PR?

[gkz]

Thinking about the ->* and function* syntax, I think it might be a better idea to add the use of * when initially parsing, rather than parsing * seperately. This would mean adding * to the arrow regex and adding function* as a keyword.

[vendethiel]

I started off with that, but it would double code here : https://github.com/gkz/LiveScript/blob/master/src/lexer.ls#L593

[duralog]

whatever... it's just a test. I think it's actually better to do the whole test suite utilizing with both harmony enabled and disabled (make sure harmony doesn't break something).

if not process.env.HARMONY_ENABLED and process.versions.node.substr(0,4) is \0.10
  spawn \node, [\--harmony, __filename], env: process.env <<< HARMONY_ENABLED: \yep
# buncha tests...
if process.env.HARMONY_ENABLED
  require './test.harmony'

[igl]

Isn't it possible to add the * automatically when yield is used in the function body?

[duralog]

yes, it is, but you wouldn't want that in some cases. imagine this:

fs.readFile 'package.json', (err, data) ->
  do_something
  lala = yield something
  do_something_else lala

which if you combined this with a package like co it might be useful... it could turn into:

fs.readFile 'package.json', (err, data) ->
  do_something
  (co ->*
    lala = yield something
  )(err, lala) ->
    if err then throw err
    do_something_else lala

which is sorta the stuff I was thinking about for making the language better
bueno, at least it should give a better error saying that you are using yield in an unstarred function.

[off-by-some]

I request we rename LiveScript to "Arrow"

[gkz]

Let's work on branch:
https://github.com/gkz/LiveScript/tree/generators

[naturalethic]

How about:
foo* = func()
for:
foo = yield func()

[naturalethic]

Or even:
foo = *func()

[naturalethic]

So who's gonna fork LiveScript to presume every function is a generator? Does that even make sense?