front.elements.implementation

Helpers for binding concrete UI component factories to front element classes.

implement_component is a small factory that produces a render-able front element class from any callable component factory (e.g. a Streamlit widget), wiring the factory’s keyword arguments to the element’s attributes.

Functions

implement_component(base_cls, component_factory)

Make a base_cls subclass whose render calls component_factory with the element's attributes.

front.elements.implementation.implement_component(base_cls, component_factory, input_value_callback=None, **input_mapping)

Make a base_cls subclass whose render calls component_factory with the element’s attributes.

For each keyword-able parameter of component_factory, the element attribute of the same name (or of the name given in input_mapping) is passed, unless it is None; callable attributes are called first. The value returned by the factory is handed to input_value_callback(value, element) if given, and returned.

>>> from dataclasses import dataclass
>>> from front.elements import FrontComponentBase
>>> def widget(label, value=0):
...     return f"{label}={value}"
>>> @dataclass
... class LabelBase(FrontComponentBase):
...     label: str = None
...     value: int = 0
>>> Component = implement_component(LabelBase, widget)
>>> Component(label='n', value=7)()
'n=7'

With input_mapping, the factory’s label is fed from the element’s name:

>>> seen = []
>>> Component = implement_component(
...     LabelBase, widget, input_value_callback=lambda v, el: seen.append(v), label='name'
... )
>>> Component(name='count', value=2)()
'count=2'
>>> seen
['count=2']