Data binding substitution failure on empty string

[ZombieRaccoon]

Hello,

I've recently encountered a phenomenon where binding an array of strings (ie. std::vector<Rml::String>) that may contain empty ones to a dropdown list using data-for results in the iterator name not being substituted in case of the empty ones.

The definition of the dropdown list looks something like this (the data variables are deliberately self-explanatory):

<select data-value="current_selection_index">
    <option data-for="array_of_strings" data-value="it_index">{{ it }}</option>
</select>

When rendered, the result is along the lines of the following:

<select value="0">
    <option selected value="0">lorem</option>
    <option value="1">{{ it }}</option>
    <option value="2">ipsum</option>
</select>

When the list contains only an empty string, then the following warnings are triggered:

Could not find variable name 'it' in data model.
Error in data expression at 4. Could not find data variable with name 'it'.
  " it "
       ^
Could not add data-text view to element: #text < selectvalue < select < body < #root#test.rml

Can you also confirm this issue? I've spent some time debugging the code, but I found the data binding logic quite complex overall without being in knowledge of its basic principles.

[mikke89]

Thanks! This was a bug indeed. Does not seem to have anything to do with the select/option/data-for in particular, just data text views not working properly when initialized with empty strings.

Let me know if the changes fix the issue for you.

[ZombieRaccoon]

It works like a charm. Thanks for the prompt response!