Thanks Jay.
On Mon, Jan 11, 2016 at 11:15 AM, Jay McCarthy <jay.mccar...@gmail.com>
wrote:
> Hi Marc,
>
> Most formlets are typed as `(formlet/c (or/c false/c binding?))` where
> the `binding?` is returned when the thing is there and the `#f` is
> returned when it isn't. However, if you use `required`, then an
> exception is thrown on the `#f` because the form element must be
> present. Formlets like `input-string` include a call to `required`. I
> think that you either want to handle the `#f` or use `default` to have
> a default value present. Similarly most formlets like `text-input`
> have an optional `#:value` keyword for starting them off with a value.
>
>
Since I use radio-group, is there a way to make it not blow up if it
doesn't get a value on any button, it seems that it works differently from
the text inputs. Of course, I could hack this by adding a hidden button and
marking it as checked, but that's a bit of a hack (not that I am opposed to
hacks).
> I think a better form DSL could be built out of formlets that
> automatically did client & server-side checking with looping
> re-submission until correct, etc. But that's not what formlets are yet
> and you have to roll it yourself.
>
> Jay
>
>
I thought so.
A related question on radio-groups though: #:display allows me to add some
custom HTML per radio input, but only after the radio input tag. Is there a
way to wrap each radio input in a div? I ask because I am using Bootstrap
for styling, which requires the following HTML:
<div class="radio">
<label>
<input type="radio" name="optionsRadios" id="optionsRadios1"
value="option1">
Option one is this.
</label></div>
Is this something that would be easy to add to (some version of)
radio-group? I am using this in several places (different radio groups), so
I would really like to leverage the formlet-process and formlets-display
abstraction, but I don't see how I would build a custom radio-group/wrap
that takes advantage of formlets by picking only the checked radio, gives
them all the same name, yet allows me to wrap it all.
Thanks for all the replies, hopefully at some point I actually understand
what I am doing and can answer questions.
Marc
>
> On Sun, Jan 10, 2016 at 9:05 PM, Marc Kaufmann
> <marc.kaufman...@gmail.com> wrote:
> > Thanks.
> >
> > Another question about formlets: when I use (formlet-process
> formlet-name)
> > it will often raise errors when a field doesn't have a value. Is there an
> > easy way of capturing errors, in particular to show the form as it was
> > entered by the user, but with an error message at the top, rather than
> > blowing up?
> >
> > One way I can imagine doing this is to catch the errors via
> (with-handlers
> > ... ), and then resend the form with previous answers pre-populated. So,
> I
> > would do the following, where 'answer' is the string ("Yes" or "No") that
> > was associated with the checked answer previously.
> >
> > (define (rg-formlet answer)
> > (define (was-answer? a)
> > (equal? a answer))
> > (formlet
> > (label
> > ,{(radio-group '("Yes" "No") #:checked was-answer?) . => . answer})
> > answer))
> >
> > Is this the way to do it, or is there an easier way (since forms with
> > missing elements can't be such a rarity - and yes, I'll do checking on
> the
> > client-side as well).
> >
> > Thanks,
> > Marc
> >
> > On Sun, Jan 10, 2016 at 5:08 PM, Jay McCarthy <jay.mccar...@gmail.com>
> > wrote:
> >>
> >> On Sun, Jan 10, 2016 at 3:50 PM, Marc Kaufmann
> >> <marc.kaufman...@gmail.com> wrote:
> >> > Hi,
> >> >
> >> > I manage to get the basic formlets to work, and tried the radiogroup,
> >> > but it
> >> > fails with the following error: "input-group: invalid selection #f",
> >> > even
> >> > though I had it selected. After some playing around, I saw that there
> >> > are
> >> > two input_0 fields being sent on submit, since I have another formlet
> on
> >> > the
> >> > same page (with a separate formlet-display and formlet-process).
> >> >
> >> > My question is: If I use formlets, do I have to put all the formlets
> >> > into
> >> > one big formlet on every page, as otherwise fields will have the same
> >> > name
> >> > attribute, and there will be clashes?
> >>
> >> Each form can have only one formlet. There can be different forms on a
> >> page, I believe.
> >>
> >> Jay
> >>
> >> > Thanks,
> >> > Marc
> >> >
> >> >
> >> > --
> >> > You received this message because you are subscribed to the Google
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> >> > "Racket Users" group.
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> >> > For more options, visit https://groups.google.com/d/optout.
> >>
> >>
> >>
> >> --
> >> Jay McCarthy
> >> Associate Professor
> >> PLT @ CS @ UMass Lowell
> >> http://jeapostrophe.github.io
> >>
> >> "Wherefore, be not weary in well-doing,
> >> for ye are laying the foundation of a great work.
> >> And out of small things proceedeth that which is great."
> >> - D&C 64:33
> >
> >
>
>
>
> --
> Jay McCarthy
> Associate Professor
> PLT @ CS @ UMass Lowell
> http://jeapostrophe.github.io
>
> "Wherefore, be not weary in well-doing,
> for ye are laying the foundation of a great work.
> And out of small things proceedeth that which is great."
> - D&C 64:33
>
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