backup values

README.md

@@ -35,5 +35,7 @@ Formidable defines a typeclass [`Form[T]`](formidable/src/main/scala/Form.scala)
 
 Automatic derivation is achieved using [Magnolia](https://github.com/softwaremill/magnolia).
 
+It keeps backups of already entered data wherever it can, to help the user.
+
 
 

build.sbt

@@ -23,7 +23,7 @@ inThisBuild(
 
 val versions = new {
   val outwatch  = "1.0.0-RC13"
-  val colibri   = "0.7.8"
+  val colibri   = "0.7.8+10-e7dd4fb2-SNAPSHOT" // https://github.com/cornerman/colibri/pull/275
   val funPack   = "0.3.2"
   val scalaTest = "3.2.12"
 }

cypress/e2e/spec.cy.js

@@ -188,4 +188,47 @@ describe('Form interactions', () => {
       cy.get('.value').should('have.text', 'Cons(Cat(,4),Cons(Dog(,true),Nil))')
     })
   })
+
+  it('backup entered values (sealed trait)', () => {
+    cy.get('.Pet').within(($form) => {
+      cy.get('select').select('Cat')
+      cy.contains('tr', 'name:').find('input[type="text"]').clear().type('Tiger')
+      cy.get('select').select('Dog') // select different case
+      cy.get('select').select('Cat') // back to previously selected case
+      cy.get('.value').should('have.text', 'Cat(Tiger,4)') // test default value
+    })
+  })
+
+  it('backup entered values (Option[Int])', () => {
+    cy.get('.Option\\[Int\\]').within(($form) => {
+      cy.get('input[type="checkbox"]').check()
+      cy.get('input[type="text"]').clear().type('15')
+      cy.get('input[type="checkbox"]').uncheck()
+      cy.get('input[type="checkbox"]').check()
+      cy.get('.value').should('have.text', 'Some(15)')
+    })
+  })
+
+  it('backup entered values (Option in case class)', () => {
+    cy.get('.Company').within(($form) => {
+      cy.contains('tr', 'address:').find('input[type="checkbox"]').check()
+      cy.contains('tr', 'city:').find('input[type="text"]').clear().type('Madrid')
+      cy.contains('tr', 'address:').find('input[type="checkbox"]').uncheck()
+      cy.contains('tr', 'address:').find('input[type="checkbox"]').check()
+      cy.get('.value').should('have.text', 'Company(,Some(Address(Madrid,)))') // test default value
+    })
+  })
+
+  it('backup entered values (nested sum types)', () => {
+    cy.get('.GenericLinkedList\\[Pet\\]').within(($form) => {
+      cy.get('select').select('Cons')
+      cy.contains('tr', 'name:').find('input[type="text"]').clear().type('Dog')
+      cy.contains('tr', 'head:').within(($form) => {
+        cy.get('select').select('Dog')
+        cy.get('select').select('Cat')
+      })
+
+      cy.get('.value').should('have.text', 'Cons(Cat(Dog,4),Nil)')
+    })
+  })
 })

demo/src/main/scala/Main.scala

@@ -16,6 +16,9 @@ object Pet {
   case class Cat(name: String, legs: Int = 4) extends Pet
 }
 
+case class Address(city: String, street: String)
+case class Company(name: String, address: Option[Address])
+
 case class Tree(value: Int = 2, children: Seq[Tree])
 
 sealed trait BinaryTree
@@ -50,6 +53,7 @@ object Main extends Extras {
       formFrame[Vector[Int]]("Vector[Int]"),
       formFrame[(Int, String, Option[Long])]("Tuple"),
       formFrame[Person]("Person"),
+      formFrame[Company]("Company"),
       formFrame[Pet]("Pet"),
       formFrame[Tree]("Tree"),
       formFrame[BinaryTree]("BinaryTree"),

formidable/src/main/scala-2/Form-Scala2.scala

@@ -2,6 +2,7 @@ package formidable
 
 import outwatch._
 import colibri.reactive._
+import scala.collection.mutable
 
 import magnolia1._
 
@@ -15,13 +16,23 @@ trait FormDerivation {
     override def default: T = ctx.construct(param => param.default.getOrElse(param.typeclass.default))
 
     override def render(state: Var[T], config: FormConfig): VModifier = Owned.function { implicit owner =>
-      val subStates: Var[Seq[Any]] =
+      println(s"product[${ctx.typeName.short}]: rendering")
+      val combinedFieldState: Var[Seq[Any]] =
         state.imap[Seq[Any]](seq => ctx.rawConstruct(seq))(_.asInstanceOf[Product].productIterator.toList)
 
-      subStates.sequence.map { subStates =>
+      combinedFieldState.sequence.map { fieldStates =>
+        println(
+          s"product[${ctx.typeName.short}]: state changed: ${ctx.parameters
+              .map(_.label)
+              .zip(fieldStates.map(_.now()))
+              .map { case (label, value) =>
+                s"$label: $value"
+              }
+              .mkString(",")}"
+        )
         config.labeledFormGroup(
           ctx.parameters
-            .zip(subStates)
+            .zip(fieldStates)
             .map { case (param, subState) =>
               val subForm = ((s: Var[param.PType], c) => param.typeclass.render(s, c))
                 .asInstanceOf[(Var[Any], FormConfig) => VModifier]
@@ -38,18 +49,45 @@ trait FormDerivation {
       defaultSubtype.typeclass.default
     }
     override def render(selectedValue: Var[T], config: FormConfig): VModifier = Owned.function { implicit owner =>
+      println(s"sum[${ctx.typeName.short}]: rendering")
+
+      val valueBackup = mutable.HashMap.empty[Subtype[Form, T], T].withDefault(_.typeclass.default)
       val selectedSubtype: Var[Subtype[Form, T]] =
-        selectedValue.imap[Subtype[Form, T]](subType => subType.typeclass.default)(value => ctx.split(value)(identity))
+        selectedValue.imap[Subtype[Form, T]](subtype => valueBackup(subtype)) { value =>
+          val subtype = ctx.split(value)(identity)
+          valueBackup(subtype) = value
+          subtype
+        }
+
+      val subFormBackup = mutable.HashMap.empty[Subtype[Form, T], (Var[T], VModifier)]
 
       config.unionSubform(
         config.selectInput[Subtype[Form, T]](
           options = ctx.subtypes,
           selectedValue = selectedSubtype,
           show = subtype => subtype.typeName.short,
         ),
-        subForm = selectedValue.map { value =>
-          ctx.split(value) { sub =>
-            VModifier.when(value.isInstanceOf[T])(sub.typeclass.asInstanceOf[Form[T]].render(selectedValue, config))
+        subForm = selectedValue.map { newValue =>
+          println(s"sum[${ctx.typeName.short}]: state changed: $newValue")
+          ctx.split(newValue) { subtype =>
+            val (formState, form) = subFormBackup.getOrElseUpdate(
+              key = subtype,
+              defaultValue = {
+                val formInstance = subtype.typeclass.asInstanceOf[Form[T]]
+                val state        = Var(formInstance.default)
+                val form         = formInstance.render(state, config) // TODO: this is lazy and always re-rendered....
+                (state, form)
+              },
+            )
+
+            println(subFormBackup.size)
+
+            formState.set(newValue)
+
+            VModifier(
+              VModifier.managedEval(formState.observable.unsafeForeach(selectedValue.set)),
+              form,
+            )
           }
         },
       )

formidable/src/main/scala/FormConfig.scala

@@ -15,7 +15,9 @@ trait FormConfig {
     div(display.flex, VModifier.style("gap") := "0.5rem", subForms)
   def labeledFormGroup(subForms: Seq[(String, VModifier)]): VModifier =
     table(
-      subForms.map { case (label, subForm) => tr(td(b(label, ": "), verticalAlign := "top"), td(subForm)) }
+      subForms.map { case (label, subForm) =>
+        tr(td(b(label, ": "), verticalAlign := "top"), td(subForm))
+      }
     )
 
   def formSequence(subForms: Seq[VModifier], addButton: VModifier): VModifier =

formidable/src/main/scala/instances.scala

@@ -58,10 +58,15 @@ package object formidable {
   implicit def optionForm[T: Form]: Form[Option[T]] = new Form[Option[T]] {
     def default = None
     def render(state: Var[Option[T]], config: FormConfig) = Owned {
+      var valueBackup: Option[T] = None
       val checkboxState = state.transformVar[Boolean](_.contramap {
-        case true  => Some(Form[T].default)
+        case true =>
+          valueBackup.orElse(Some(Form[T].default))
         case false => None
-      })(_.map(_.isDefined))
+      })(_.map { value =>
+        value.foreach(some => valueBackup = Some(some))
+        value.isDefined
+      })
 
       config.withCheckbox(
         subForm = state.sequence.map(