If this Px contains a function, it can be extracted and the Px dropped from the signature.
If this Px contains a function, it can be extracted and the Px dropped from the signature. Every time the function
is invoked it will use the latest value of this Px, even if you don't explicitly hold a reference to it anymore.
Example. From a Px[Int => String], an Int => String can be extracted.
Get the last used value without updating.
Revision of its value.
Get the latest value, updating itself if necessary.
A variable in the traditional sense.
Doesn't change until you explicitly call
set().