FormFunction default display

Question

I am trying to use FormFunction[] to input data in my notebook. As it shows up when using FormFunction in a notebook (no web deploy) no default values are displayed (even if specified) only empty input fields although the defaults are returned correctly when accepting the Form.

Bug or feature ? Is there any option to enable the initial display of default values?

Meanwhile I came up with the following solution:

---

FormFunctionInit[l_, "Init" -> True] :=  
 FormFunction[FormObject[l][Cases[l, (a_ -> b_ -> c_) :> (a -> c)]]]  

FormFunctionInit[l_, ___] :=
 FormFunction[FormObject[l][]]

form = FormFunctionInit[
   {  
    "x1" -> "Number" -> 1,  
    "x2" -> "Number" -> 2,  
    "x3" -> "Number",  
    "x4" -> "Number" -> 4  
    }, "Init" -> True  
   ];

input = form[] // Normal

out[[3]]= {x1->1, x2->2, x3->55, x4->4}

---

Any suggestions for improvement avoiding my custom code?

Answer 1

I think you are most likely looking for the Input format. In the Details and Options section of FormFunction it specifies that you can have this form

FormFunction[formspec,func][<|"namek"->inputk,…|>]

inserts the inputs given into the form specified by FormFunction before evaluating the effect of the FormFunction.

  FormFunction[{
     "x1" -> <|"Interpreter" -> "Number", "Input" -> 1|>,
     "x2" -> <|"Interpreter" -> "Number", "Input" -> 2|>,
     "x3" -> "Number",
     "x4" -> <|"Interpreter" -> "Number", "Input" -> 4|>}][]

Notice: If you complete x3 field e.g. with number 3 then it returns the default (input) values for x1,x2,x3. In that case there is no need for a "Default". I am not sure though how these two are contrasted.

  Out= <|"x1" -> 1, "x2" -> 2, "x3" -> 3, "x4" -> 4|>