Concept for Context Providers

[CiberNin]

Something like a React context provider where you can provide a value in a parent component that is available to all the children.
I've actually gotten this sort of working with only a small change to syntax, although I have no idea at to performance.
TestIndex.jinja

<TestOuter model="A">
  <TestWrapper>
    <TestWrapper>
      <TestInner name="AA" />
    </TestWrapper>
  </TestWrapper>
</TestOuter>

Gets preprocessed into:

{% call(context) catalog.irender("TestOuter", **{"model":"A", "context":context| default(None)}) -%}
  {% call(context) catalog.irender("TestWrapper", **{"context":context| default(None)}) -%}
    {% call(context) catalog.irender("TestWrapper", **{"context":context| default(None)}) -%}
      {{ catalog.irender("TestInner", **{"name":"AA", "context":context| default(None)}) }}
    {%- endcall %}
  {%- endcall %}
{%- endcall %}

via this change to jinjax.py

Line 12 : BLOCK_CALL = '{% call(context) [CMD]("[TAG]"[ATTRS]) -%}[CONTENT]{%- endcall %}'
_build_call
Line 135 : attrs.append("\"__context\":context| default(None)")

Incidentally this _build_call appears to have an unneeded list comprehension when generating str_attrs.

And then I changed catalog.py so that you now use caller() like you would in a normal jinja macro instead of just content.
But I wrap it so that context is passed in & can be updated by keyword arguments.
TestOuter.jinja

{#def model#}
<div class="Outer">
  Model : {{model}}
  Context : {{context}}
  Content : {{caller(model = model)}}
</div>

catalog.py added lines to irender:

context = kw.pop("context", {}) or {}
...
 # props[PROP_CONTENT] = content if content or not caller else caller().strip()
props["context"] = context
context: dict
def caller_wrapper(**kwargs):
    updated_context = context.copy()
    updated_context.update(kwargs)
    return caller(updated_context)

props["caller"] = caller_wrapper

This is all meant to support creating some neat datagrid ideas I had where a single field component renders contextually depending on it's in a datagrid or a form or if the datagrid is editable or to reuse the field in both the header and the body of the table.

<Page title="Tools">
  {% with selected_tool = None %}
    <AForm name="Tool" key={selected_tool}>
       <Field name="toolid"/>
       <Field name="description"/>
       <Field name="grit"/>
       <Field name="dateupdated"/>
    </AForm>
    <Datagrid model="ToolIndex">
      {% set selected_tool = context.selected_row.toolid %}
      <Field name="toolid"/>
      <Field name="description"/>
      <Field name="dateupdated"/>
    </Datagrid>
  {% endwith %}
</Page