ComboBox entry fails to update?

[bredelings]

Hi, I'm new to enaml, and I can't figure out why a ComboBox entry fails to update until the entire ComboBox is recreated (I think) because a new entry is added.

Part of the code looks like this:

        ObjectCombo: combo:
            items << [index for index in range(len(model.smodels))]
            to_string = lambda index: model.get_substitution_model_name(index)
        Conditional:
            condition << combo.selected is not None
            SubstitutionModelView:
                 smodel := model.smodels[combo.selected]

It seems that the ComboBox names (generated by the to_string lambda) don't get updated when the function value changes. However, if we add a new item to the ComboBox, then the number of items changes and the updated string is used. Am I missing something here?

This is a reduced testcase, the real case involves field names not updating in a table until I add a new row.

[bredelings]

from enaml.core.api import Conditional, Looper

from atom.api import Atom, Str, Range, Bool, Value, Int, Tuple, observe, ContainerList

from enaml.widgets.api import (
    Window, Label, Field, Form, DateSelector, CheckBox, GroupBox, Container,
    PushButton, MainWindow, MenuBar, Notebook, Page, FileDialogEx, ToolBar, ActionGroup, Action, VGroup, ObjectCombo
)

from enaml.widgets.menu import Menu
from enaml.widgets.action import Action

class Partition(Atom):
    substitution_model = Int()

class SubstitutionModel(Atom):
    name = Str()

    model = Str()

class ATModel(Atom):
    """A collection of partitions that can share models

    """

    partitions = ContainerList(Partition)
    smodels = ContainerList(SubstitutionModel)

    def get_substitution_model_name(self,index):
        print(f'get substitution model name {index}')
        if self.smodels[index].name:
            print("using the name {}".format(self.smodels[index].name))
            return self.smodels[index].name
        else:
            print("no name: using the name S{}".format(index))
            return 'S{}'.format(index+1)

    # branch_lengths = BranchLengthModel()
    def add_partition(self):
        smodel = len(self.smodels)
        self.smodels.append(SubstitutionModel(model='tn93'))

        partition = Partition(substitution_model = smodel)
        self.partitions.append(partition)

    def remove_partition(self):
        if len(self.partitions) > 0:
            self.partitions.pop()

enamldef SubstitutionModelView(Form):
    attr smodel
    Label:
        text = 'Name'
    Field:
        text := smodel.name
    Label:
        text = 'Model'
    Field:
        text := smodel.model

enamldef Main(Window):
    attr model = ATModel()
    Container:
        PushButton:
            text = 'Add partition'
            clicked :: model.add_partition()
        PushButton:
            text = 'Remove partition'
            clicked :: model.remove_partition()
        Label:
            text = 'Substitution Models'
        ObjectCombo: combo:
            items << [index for index in range(len(model.smodels))]
            to_string = lambda index: model.get_substitution_model_name(index)
        Conditional:
            condition << combo.selected is not None
            SubstitutionModelView:
                 smodel := model.smodels[combo.selected]

[MatthieuDartiailh]

Enaml has no way to track that output of the function change because some complicated inner part of you model changed. To get this to work you need induced a change on a part of the model tracked by the view. I will try to elaborate later if it is not clear.

[MatthieuDartiailh]

Closing for lack of activity.

As mentioned above enaml cannot react to a change stemming from a change in behavior inside a function. Passing as arguments all the elements that should cause a recomputation is one way to avoid the issue.