Here is the example with better rendering and additional information as well as some identifies issues to be solved.
http://haskell-web.blogspot.com.es/2013/06/the-promising-land-of-monadic-formlets.html And I made strong statements there. What do you think? If you have questions or want to be involved in the development of this and other related concepts, please send me a message. 2013/6/20 Alberto G. Corona <agocor...@gmail.com> > I don´t know how, but the google mail has changed the applicative functor > operator after (,) Left and Rigth by "<-". > > > > > 2013/6/19 Alberto G. Corona <agocor...@gmail.com> > > Hi, >> >> This is just to let you know the promising results of some >> experimentation: >> >> Formlets are about applicative instances, but what about monadic >> instances? What a Monad instance of formlets means? I recently experimented >> with this and the results are very interesting and powerful- It mixes the >> best of web forms, with the flexibility of console applications. ???!!!!!! >> >> >> Althoug this example is for the formlets of the MFlow >> <https://github.com/agocorona/MFlow>framework , it can be ported to >> other formlet implementations. Although the MFLow formlets include web >> formatting that is not supported in other formlets implementations. Static >> HTML templating don´t work well with monadic formlets, so it is important >> to include the formatting as a part of the computation: >> >> import MFlow.Wai.Blaze.Html.All >> >> dynamicForm= wform $ do >> (n,s) <- (,) <- p << "Who are you?" >> ++> getString Nothing <! hint "name" <++ br >> <*> getString Nothing <! hint "surname" <++ br >> <** submitButton "ok" <++ br >> >> flag <- b << "do you " ++> getRadio[radiob "work?",radiob "study?"] >> <++ br >> >> r<-case flag of >> "work" -> pageFlow "l" >> $ Left <- b << "do you enjoy your work? " >> ++> getBool True "yes" "no" >> <** submitButton "ok" <++ br >> >> "study"-> pageFlow "r" >> $ Right <- b << "do you study in " >> ++> getRadio[radiob "University" >> ,radiob "High School"] >> >> p << ("You are "++n++" "++s) ++> >> case r of >> Left fl -> p << ("You work and it is " ++ show fl ++ " that >> you enjoy your work") >> ++> noWidget >> >> Right stu -> p << ("You study at the " ++ stu) >> ++> noWidget >> >> >> hint s= [("placeholder",s)] >> onClickSubmit= [("onclick","this.form.submit()")] >> radiob s n= text s ++> setRadio s n <! onClickSubmit >> >> Here wform, getBool, getString , getRadio etc are formlet elements >> >> The first sentence is an applicative composition that generate a 2 tuple, >> to show that applicative and monadic can be mixed. the operations ++> add >> html to the formlet. the operatior <! add attributes to the formlet >> element.. noWidget is a dumb formlet that does not validate. >> >> The second monadic statement is an election between two options. The >> beauty of the monadic instance is that the rest of the form can vary >> depending on the previous answers. Since the formlets validate the input, >> unless the election is made, the radio will not validate, so the monadic >> execution will be aborted beyond any unanswered question, so nothing will >> appear after the question. The rest of the form will appear when the user >> choose one of the two options. once one or the other option is chosen, then >> another binary question is presented. (either he likes his work or where he >> study). When the questions are finised, the results are presented. >> I hope that you get the idea. The benefit is not only the familiar coding >> and presentation of a sequential console application: Since the form >> encloses all the fields, At any time the user can change previous inputs >> and the form will reflect these changes. For example if the user change >> from work to study (second statements) the "where do you study will appear >> and the work related questions and answers will disappear. That is >> wonderfully useful for heavily interactive applications. >> >> There is a problem however and it is the issue of the formlet >> identifiers. Unlike in an applicative presentation, now the number and type >> of the formlets will vary, so the response to a previous form create a new >> kind of form, and the post response can be misinterpreted. To avoid that , >> the pageFlow call creates fixed field labels for each branch of execution. >> >> I will release a version of MFlow that support this kind of monadic >> composition of fomlets, but In essence it is nothing but to add Monad >> instance to formlets. A single server procedure, that executes the formlet >> code can support all the interaction so any framework can do it. The >> usability of that is huge:It is possible to interact in a web page in a >> console style with questions and answers with the versatitly of a dynamic >> foms: Any modification in the form change the subsequent flow of >> interaction. Another application of this monadic style is to ease multistep >> processes such are registration, check-out and payment ad so on. Even a >> entire interactive dynamic application can be coded in a single page. >> >> And no javascript is needed!. >> >> >> To run this formlet in MFlow: >> >> main=do >> addMessageFlows >> [("" , transient $ runFlow $ ask dynamicForm )] >> >> wait $ run port waiMessageFlow >> >> >> This video show how the presentation of this example vary with the user >> input: >> >> http://youtu.be/DryBQc9agFg >> >> >> I hope that you find the idea interesting. If you want to experiment >> with this in MFlow, I have to say that the implementation of this feature >> is in an early stage. The code is in the head branch >> >> https://github.com/agocorona/MFlow/tree/head >> >> >> >> Alberto. >> > > > > -- > Alberto. > -- Alberto.
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