Creates a new FunctionsStore with the given functions.
Inserts a function into the store, keyed by its id (known) or name (named).
The name the store assigned to func, if it is registered: the
registered function's own name (its assigned name, or its number when
it has none), as the reference's assigned_name returns the name it
filed at insertion.
Returns the name for a function, either from this store or from the function itself.
The registered functions.
An independent copy (a format context takes one, as the reference does).
StaticnameThe function's name in store when registered there, else its own name (name_for_function).
Optionalstore: FunctionsStore
A store that maps functions to their assigned names.
FunctionsStore maintains a registry of functions and their human-readable names, which is useful for displaying and debugging expression functions.