Re: [Haskell-beginners] Options for creating a multiple select form via Yesod

I was a bit hasty. I can render a multi-select field easily enough. However, I'm having difficulty following how selectField makes a value from the select field accessible from the handler code calling selectField. Once I figure that out, I can modify multiSelectField accordingly. The goal here being to modify selectField so that a list of field values can be bound . Here's what I have so far: multiSelectField is thus far identical in every way to selectField save for the following change in the Hamlet part. <select multiple="#{theId}" id="#{theId}" name="#{name}"> My thinking was that the value bound to multiple was arbitary, and I'd use theId until I figured out something that made more sense. Here's where I am focusing my efforts next http://hpaste.org/47774 Specifically (x', _):_ -> case lookup x' pairs' of Nothing -> FormFailure ["Invalid entry"] Just (y, _) -> FormSuccess y I'm thinking this is where selectField binds a value from the select field form. I'm confused by the (x',_):_. At first I thought it meant that just the first pair in a list of pairs is pattern matched against, and the rest discarded. But then I ask myself where the list is coming from. In a select field there would only be one pair, not a list of them. Here's where I get confused. Because if this is not where the values of the select field get bound, I don't know where it's happening. Is my confusion clear enough such that I could get some clarifying feedback? If not, what is unclear? On Sat, Jun 11, 2011 at 11:03 AM, Michael Snoyman wrote:

The best way for code contributions in general is to submit a pull request on Github. If that's a problem, sending a patch via email works as well (either directly to me or to web-devel).

Michael

On Sat, Jun 11, 2011 at 1:14 AM, Michael Litchard wrote:

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Hey! I just added multiSelectField to the Forms library. I'm only getting the first value selected, but I think that's because of how I'm using multiSelecrField. I'm going to try to change the client code to fix this. I'll let you know how it goes. when I get a maybeMultiSelectField added I'll show you what I have. What would be the best way to submit this?

On Thu, Jun 9, 2011 at 10:05 PM, Michael Snoyman wrote:

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Hi Michael,

There's nothing jQuery or Javascript specific about a multi-select field: it's just a normal select field with a "multiple" attribute. I would recommend taking the selectField code from yesod-form and modifying it to be multi-select. I'll likely do this myself eventually, but it could be a good learning experience in Yesod (and a great introduction to contributing to the framework if you're so inclined).

Michael

On Thu, Jun 9, 2011 at 8:29 PM, Michael Litchard wrote:

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I'm trying to create a multiple select form, as illustrated on the following: http://api.jquery.com/selected-selector/

Here's the options I see possible:

(1) Write a jQuery widget. (2) Use plain javascript via Julius (3) Use the low-level functions in Yesod.Form to write a widget (4) Use a pre-existing function that does what I need, but am not aware of this functionality

(1) has appeal as it looks like something small I can contribute to the project. It will take me some extra time to figure out the details. But, I had a look at the other jQuery widgets and they seem to provide an approachable model to follow.

(2) This looks like the most straight-forward approach. I'm just learning javascript so would have to figure out how to capture values in Haskell from the form.

(3) This looks like the most difficult way. I don't think I know enough about the low-level functions in Yesod.Form to be able to accomplish this in a timely manner.

(4) This is the best scenario. There's already a way to do this right now, and I just haven't identified it. If this is the case, I would appreciate being pointed in the right direction.

Until informed otherwise, I'm evaluating options 1 and 2. All feedback welcomed. Thanks to all who made Yesod possible.

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