[web-devel] Re: [Haskell-cafe] Google Summer of Code: BlazeHTML RFC

[Jasper Van der Jeugt]

On Thu, May 27, 2010 at 8:31 PM, Matt Parker <moonmaster9000 at gmail.com> wrote:
> will it be possible to easily interleave IO values into the HTML? like
> instead of the [1,2,3]
>
> ul $ forM_ [1, 2, 3] (li . string . show)
>
> what if it was a function that returned IO [1,2,3] (maybe 1,2,3 came out of
> a database). will the forM_ handle that OK?

Depends on how you write the code. More precisely, it depends on in
which monad the forM_ takes place. Also, I would not recommend
interleaving IO values into the HTML, because the HTML is pure -- you
usually don't want to mix that with IO. I'd rather write something
like:

    numbers <- getFromDataBase
    return $ ul $ forM_ numbers (li . string . show)

Or it could be possible to store your templates in a separate modules,
and they would all have a pure type signature:

    templateX :: Arg1 -> Arg2 -> Html a

I think this would be the preferred way, because it allows a
separation between the pure View code and the IO-interleaved
Controller code in a web application.

Kind regards,
Jasper Van der Jeugt

On Thu, May 27, 2010 at 8:31 PM, Matt Parker <moonmaster9000 at gmail.com> wrote:
> will it be possible to easily interleave IO values into the HTML? like
> instead of the [1,2,3]
>
> ul $ forM_ [1, 2, 3] (li . string . show)
>
> what if it was a function that returned IO [1,2,3] (maybe 1,2,3 came out of
> a database). will the forM_ handle that OK?
>
>
> On Thu, May 27, 2010 at 12:19 PM, Matt Parker <moonmaster9000 at gmail.com>
> wrote:
>>
>> Blaze HTML looks wonderful to me (especially with the do notation), and
>> better then Hamlet for one reason: writing idiomatic haskell for stuff like
>> this:
>>
>> ul $ forM_ [1, 2, 3] (li . string . show)
>>
>> instead of the Hamlet style:
>>
>> %ul
>>   $forall children.person child
>>     %li $child$
>>
>> which, i don't know, for some reason, made me feel like i was back in PHP
>> land.
>>
>> -matt
>>
>>
>> On Thu, May 27, 2010 at 7:08 AM, Alberto G. Corona <agocorona at gmail.com>
>> wrote:
>>>
>>> As a user, I have too many HTML generators, a few of them with Ajax and
>>> none with server-side event handling (like ASPX or JSPX).  Ajax is
>>> complicated but server side event handling is  what I really miss because it
>>> is simple  from the user point of view, my ervents could be handled in
>>> haskell code rather than in javaScript and I  implicitly could  use the
>>> advantages of  dinamic HTML and Ajax without the need to know them at all.
>>> Imagine a dynamic Web application  with 100% haskell code made with
>>> dynamic widgets created by third party developers.
>>> So, anyone want to create a HTML templating system with server side event
>>> handling? It is not terribly hard to do. (I refer to ASP.NET documentation
>>> or the JavaServer Faces framework).
>>> By the way, I vote for XML templating or else, combinator templating that
>>> produce XHML templating because it can be handled by a future graphical IDE.
>>>
>>> 2010/5/27 Jasper Van der Jeugt <jaspervdj at gmail.com>
>>>>
>>>> Hey Bas,
>>>>
>>>> > How about also providing an enumerator back-end?
>>>> >
>>>> > http://hackage.haskell.org/packages/archive/iteratee/0.3.5/doc/html/Data-Iteratee-Base.html#t%3AEnumeratorGM
>>>> >
>>>> > Then your library can integrate more easily with the snap framework:
>>>> > http://snapframework.com
>>>>
>>>> Sure, I can do that. But I already tested integration with the snap
>>>> framework, the best path here seems to call the `writeLBS` function
>>>> from the snap framework on the `L.ByteString` that BlazeHtml produces
>>>> (`writeLBS` internally uses an enumerator).
>>>>
>>>> Kind regards,
>>>> Jasper Van der Jeugt
>>>>
>>>> On Thu, May 27, 2010 at 10:38 AM, Bas van Dijk <v.dijk.bas at gmail.com>
>>>> wrote:
>>>> > Q14: Do you see any problems with respect to integrating BlazeHtml in
>>>> > your favourite web-framework/server?
>>>> >
>>>> > How about also providing an enumerator back-end?
>>>> >
>>>> > http://hackage.haskell.org/packages/archive/iteratee/0.3.5/doc/html/Data-Iteratee-Base.html#t%3AEnumeratorGM
>>>> >
>>>> > Then your library can integrate more easily with the snap framework:
>>>> > http://snapframework.com
>>>> >
>>>> > Regards,
>>>> >
>>>> > Bas
>>>> >
>>>> _______________________________________________
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>>>
>>>
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>>
>
>