Forbidding use of multiple values with unnamed values

I forbid Actions to declare both an unnamed value and named values.
In a far future, the action name alone will imply passing the full structure.
Example:
d1: DISTANCE ATOMS=1,2 COMPONENTS
now only declared d1.x d1.y and d1.z, whereas d1 cannot be accessed
directly as a value (since it is a complex structure that we cannot handle
yet)