Re: [web-devel] Hoogle Advice

On Tue, Jan 25, 2011 at 8:53 PM, Bardur Arantsson wrote:

On 2011-01-25 09:49, Michael Snoyman wrote:

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On Tue, Jan 25, 2011 at 9:33 AM, Bardur Arantsson  wrote:

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On 2011-01-25 02:14, Jeremy Shaw wrote:

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On Mon, Jan 24, 2011 at 4:38 PM, Neil Mitchell  wrote:

[--snip--] The thing I'd like to see is really more *framework-independent* code for things like session handling, cookie handling, etc. I really like the 'http' package for this reason. It does exactly one thing and (mostly) doesn't get in the way of whatever else you're trying to do.

Maybe some of this 'generic' stuff could be put in WAI middleware -- then at least Neil and I could share that code :).

I've been making a big push to get framework-agnostic code separated out into separate packages wherever possible. For your case you may want to look at the cookie and clientsession packages. Additionally, you may want to consider using blaze-html for the HTML generation, or even Hamlet.

I've already settled on blaze-html... a lot less fidgeting with string concatenation, etc. plus it seems to perform extremely well.

Hamlet isn't really useful for my purposes -- I really want *ALL* the client-side HTML/JS/etc. to be generated by widgets/components and my framework users shouldn't write any HTML directly. This HTML will also be injected into the page dynamically as the user interacts with the UI, so blaze-html is great.

For your use case, blaze-html *does* sound like the way to go. And I agree: it's an awesome package.

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I'd be interested in hearing more about how you are planning on implementing this framework.

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Yesod already provides built-in support

for widgets, though so far I have been very conservative about including direct Ajax features. For the most part, it is used for providing form controls that do validation. However, there's no reason it *couldn't* be used for Ajax.

I've actually implemented a little demo app in Yesod and have looked a little at the widget type/module, but as far as I can tell they don't go anywhere close to where I want to go. I don't have an actual design doc anywhere at the moment, so the only thing I can use to illustrate what I want to do is by way of pointing to Vaadin. You basically program as if you were programming an old-school graphical UI (Swing, SWT, GTK+, Tk, whatever) and the framework takes care of "translating" that to a browser application. Essentially the user should not have to write *ANY* html, JavaScript or CSS at all.

All the state transfer will happen through callbacks to the server and/or Comet-style push updates to the browser. I'm still investigating reasonable ways to implement proper state handling.

I could be wrong here, but I have the feeling that it *should* be possible to build up such a solution based on the what Yesod provides in widgets. Obviously, such a solution would add much more power than what Yesod provides, but I think it already provides enough of the low-level details to get what you need. I'm not trying to convince you to use Yesod for this, but I would be very appreciative to hear what Yesod's widgets are lacking to get the functionality you want.

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Following my normal sets of advice, I would recommend that any component that you build that is not intrinsically tied to your framework be released as a separate package so we can all benefit and share resources where relevant. And if you have questions/requests on the WAI side, just let me know.

Sure.

One thing I am looking for is a convenient way to autogenerate JavaScript. I could use the "blaze" string builders (or builders for Text or whatever), but if there is some library for building JS in a safer way than just string concatenation. As with the HTML, I'm also going to be generating this JS extremely dynamically. I know about Julius, but what I (think) I really need is a sort of AST datatype for JavaScript with a toText/toBS printer.

Alan Zimmerman put together a Javascript minification package[1], and in the process created a full-blown Javascript lexer/parser/AST package[2]. That may be somewhere do start. Michael [1] http://hackage.haskell.org/package/hjsmin [2] http://hackage.haskell.org/package/language-javascript-0.4.2