Slice using different column from the one bound to an M query parameter

Hey danextian , thank you for the conversation. 

I've found a way to do it.  The steps are:
- bind date column to a parameter date_parameter (instead of table_name.)

- in power query, look up table_name in the let statement before loading the table.

Here's the code, where SLICER_TABLE refers to

let
    my_date = Text.From(date_parameter),
    my_table = List.First(
        Table.Column(
            Table.SelectRows(SLICER_TABLE, each [DATE] = my_date)
            , "TABLE_NAME"
        )
    ),
    .... (then use my_table as the table to load)

 
I'm new to mashup, so if there's a more elegant way, please let me know.