//Add() is the method that is called in response to an element being
//added to the collection (self.todos). This is the "magic" turns an
//instance of todo into a view.
func (self *todoApp) Add(length int, newObj s5.Model) {
model := newObj.(*todo)
//note: There are two legal things that can be passed to any
//note: of the tag creation methods. Sadly, there is no way
//note: to typecheck these until runtime (it is checked then).
//note:
//note: The two legal things are some type of option, such as
//note: Class() or ModelId() that affect the resulting tag.
//note: One of the common types of "options" is something creates
//note: a constraint between a dom "piece" of the tag being
//note: being constructed and some value, usually in the model.
//note:
//note: The other leagl item is another tag, that will be added
//note: as a child of the one it is neted in. This lack of type
//note: safety has been chosen for convenience of notation.
tree :=
s5.LI(
//LI: Pass in a model ID to generate unique id for this tag,
//LI: and make easy to remove the whole subtree by id.
s5.ModelId(model),
//LI: constraint that toggles the completed property
s5.CssExistence(completed, model.done),
//LI: constraint that toggles the editing property
s5.CssExistence(editing, model.editing),
s5.DIV(
//DIV: just one CSS class to make it look nice
s5.Class(view),
s5.INPUT(
//INPUT: has a CSS class "toggle" to make it look nice
s5.Class(toggle),
//INPUT: we force the "type" of this to be the constant "checkbox" (possibly overkill)
s5.HtmlAttrEqual(s5.TYPE, s5.NewStringSimple("checkbox")),
//INPUT: make the checked attr be equal to the model's done
s5.PropEqual(s5.CHECKED, model.done),
//INPUT: when clicked, it toggles the value on the model
s5.Event(s5.CHANGE, func(e jquery.Event) {
model.done.Set(!model.done.Value())
}),
),
s5.LABEL(
//LABEL: We use a constraint to bind the name attribute of the
//LABEL: model to the label's displayed text.
s5.TextEqual(model.name),
//LABEL: Double clicking on the label causes edit mode
s5.Event(s5.DBLCLICK, func(jquery.Event) {
model.editing.Set(true)
//XXX UGH, don't have a handle to the input object
in := s5.HtmlIdFromModel("INPUT", model).Dom()
in.SetVal(model.name.Value())
in.Focus()
in.Select()
}),
),
s5.BUTTON(
//BUTTON: destroy class makes it look nice
s5.Class(destroy),
//BUTTON: click function that calls remove on the list
//BUTTON: element that was used to create this whole structure
//JQUERY: Neither of the jquery params are used.
s5.Event(s5.CLICK, func(jquery.Event) {
//note: we are calling remove on the *collection* which
//note: will end up calling the Remove() method of our
//note: joiner. If we don't tell the collection that the
//note: model was removed, we could end up with a display
//note: that doesn't correctly reflect the constraints
//note: state (since these constraints would have dependencies
//note: one items no longer visible).
self.todos.Remove(model)
}),
), //BUTTON
), //DIV
s5.INPUT(
//INPUT: Use a model to make this input easy to find
s5.ModelId(model),
//INPUT: edit CSS class to make it look nice
s5.Class(edit),
//INPUT: wire the placeholder to be name of the model... (overkill?)
s5.HtmlAttrEqual(s5.PLACEHOLDER, model.name),
//INPUT:the spec calls for escape to cancel editing with no change
//INPUT:and for return to commit the changes EXCEPT if the
//INPUT:user edited out all the text, then we should delete the
//INPUT:whole thing
//JQUERY: This uses the jquery selector to get the value of the input.
//JQUERY: This uses the event object to get the keyboard code.
s5.Event(s5.KEYDOWN, func(e jquery.Event) {
//note: This type of "event handler" is the glue that
//note: connects a user action to something that manipulates
//note: the model. Most event handlers do not need to
//note: manipulate the view as well because they have constraints
//note: that connect the model to the view.
switch e.Which {
case 13:
//This conversion is a no-op other than the go language type.
//The e.Target value is ALREADY a jquery object, but it's not
//typed correctly for this function to use conveniently.
j := s5.WrapJQuery(jquery.NewJQuery(e.Target))
v := strings.Trim(j.Val(), CUTSET)
//check for the special case of making a name==""
if v == "" {
self.todos.Remove(model)
} else {
//just reset the model name and it propagates to display
model.name.Set(v)
}
j.Blur()
fallthrough
case 27:
model.editing.Set(false)
primaryInput.Dom().Focus()
}
}),
), //INPUT
).Build()
listContainer.Dom().Append(tree)
}
//Start is called by concorde once the DOM is fully loaded. Most of the
//application intialization code should be put in here.
func (self *todoApp) Start() {
//Setup an event handler for the primary input field. The called func
//creates model instance and puts in the list of todos.
// JQUERY: Any use of jquery is suspect as it allows many non type-safe operations.
primaryInput.Dom().On(s5.CHANGE, func(event jquery.Event) {
if !self.createTodo(primaryInput.Dom().Val()) {
event.PreventDefault()
}
})
//We need to attach the self.numNotDone string to the proper place
//in the DOM. Note that we use the lower-level jquery selector
//(Select().Children())) plus NewTextAttr() we needed the string
//child of span#todo-count (so we can't use HtmlId) and because
//that object is directly in the HTML file.
// JQUERY: Any use of jquery is suspect as it allows many non type-safe operations.
selector := jquery.NewJQuery(todoCount.TagName() + "#" + todoCount.Id())
todoCountSelect := selector.Children("strong")
s5.Equality(s5.NewTextAttr(s5.WrapJQuery(todoCountSelect)), self.numNotDone)
//We need to attach the self.plural string to the proper place
//in the dom.
s5.Equality(pluralSpan.TextAttribute(), self.plural)
//These two calls attach the inverse of the empty attribute derived
//from the model collection the display property (turning them on
//when the list is not empty). Note that we can't use the simpler
//"Equality()" because we want to invert the value. The BooleanInverter
//is a built in constraint function.
sectionMain.DisplayAttribute().Attach(
s5.NewBooleanInverter(self.todos.EmptyAttribute()))
footer.DisplayAttribute().Attach(
s5.NewBooleanInverter(self.todos.EmptyAttribute()))
//This connects the display property of the clearCompleted to the boolean
//that is true if some of the elements are done. This effectively
//turns on the button when there are some elements in the list and
//some of those elements are done.
s5.Equality(clearCompleted.DisplayAttribute(), self.someDone)
//This connects the display in the button to the number of done
//elements. Note that this wont be visible if there are no
//done elements.
s5.Equality(numCompleted.TextAttribute(), self.numDone)
//This is the event handler for click on the clearCompleted
//dom element. We just walk the list of objects building a kill list,
//then we destroy all the items in the kill list
//JQUERY: Neither of the jquery params are used.
clearCompleted.Dom().On(s5.CLICK, func(jquery.Event) {
all := self.todos.All()
if len(all) == 0 {
return
}
dead := make([]s5.Model, len(all))
ct := 0
for _, model := range all {
if model.(*todo).done.Value() {
dead[ct] = model
ct++
}
}
for _, d := range dead {
self.todos.Remove(d)
}
})
//toggleAll's behavior is to toggle any items that are not already
//marked done, unless they are all marked done in which they should all
//be umarked
//JQUERY: Neither of the jquery params are used.
toggleAll.Dom().On(s5.CLICK, func(jquery.Event) {
desired := true
//Compare the output of the constraints to see if all are done
if self.todos.LengthAttribute().Value() == self.numDone.Value() {
desired = false
}
for _, m := range self.todos.All() {
m.(*todo).done.Set(desired)
}
})
//These are discussed below. These are constraints that depend
//on *all* the values in the list.
self.dependsOnAll()
}