Let me see if I can explain what I'm after better. The app that I am porting is mostly CRUD (Create Read Update Delete), one twist though is that we never explicitly use create, if a user wants to create a new record they actually edit a copy of the most recent record, so a form always has values (though not necessarily the same "default" values).
If I understand the docs, then this: http://noionlabs.com/formlets/save-formlet.rkt Is the right way to do it. The general pattern is that to have a formlets with values I need to have a formlet-maker function, that creates the formlet, and I need to save that formlet for the formlet-process function. The docs seemed to suggest that I needed to save that formlet (and not use formlet-maker to make a new one) for use with formlet-process, but this http://noionlabs.com/formlets/generate-new-formlet.rkt does work. I assume its not common/best practice though since its easy to break: http://noionlabs.com/formlets/breaks.rkt What I'd like to be able to write is: http://noionlabs.com/formlets/formlet-fill.rkt I don't really want to make a new formlet, or save it for use in the processing step, I just want to be able to modify the values in the formlet before sending it to the client. Shalom, Jordan On Fri, Nov 18, 2011 at 04:10:29PM -0700, Jay McCarthy wrote: > You need to make a new formlet that knows about the default values. > > We could imagine a macro that makes this nicer, but in general it will need > to be something that creates a new one. > > Is there some reason you don't want to do that? > > I can imagine something like (formlet-display) that took the old values, > but then it would be more monad-like than arrow-like, and wouldn't really > be a formlet. If you can clarify your use case, it may be worth > investigating. > > Jay > > On Fri, Nov 18, 2011 at 1:13 PM, Jordan Schatz <jor...@noionlabs.com> wrote: > > > > > I have a pattern of user interaction that is common in my web app: > > > > I have a db record, I present it to the user in a form, the user edits > > the form, submits it, server side logic validates it, and then returns > > the same form with the updated record. > > > > I want to port the app to Racket, and I thought formlets would be just > > the thing, but I don't see how to fill the values into the formlet > > without making a new formlet... seems I need a (formlet-fill > > (some-values)) to go along with the formlet-display and formlet-process. > > > > Here is what I have: (Which doesn't work) > > > > ---------------------------------------------------------------------- > > #lang web-server/insta > > > > (require web-server/formlets) > > > > (define record (hasheq 'title "this is a title" > > 'body "post body")) > > > > (define (start request) > > (edit-record request)) > > > > (define (edit-record request) > > (local [(define (record-formlet our-values) > > (formlet > > (#%# ,{(text-input #:value (string->bytes/utf-8 (hash-ref > > our-values 'title))) . => . title} > > ,{(text-input #:value (string->bytes/utf-8 (hash-ref > > our-values 'body))) . => . body}) > > (values title body))) > > > > (define (handle-response request) > > (define-values (title body) > > (formlet-process our-formlet request)) > > (set! record (hasheq 'title title > > 'body body)) > > (start (redirect/get))) > > > > (define (response-generator embed/url) > > (response/xexpr > > `(html > > (form ([action ,(embed/url handle-response)]) > > ,@(formlet-display our-formlet) > > (input ([type "submit"]))))))] > > > > (send/suspend/dispatch response-generator))) > > > > ---------------------------------------------------------------------- > > > > It seems like this would be a very common pattern... what is the "normal" > > way to do it? > > > > Thanks, > > Jordan > > _________________________________________________ > > For list-related administrative tasks: > > http://lists.racket-lang.org/listinfo/users > > > > > > -- > Jay McCarthy <j...@cs.byu.edu> > Assistant Professor / Brigham Young University > http://faculty.cs.byu.edu/~jay > > "The glory of God is Intelligence" - D&C 93 _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
