After consulting Wikipedia, we realized that
the Top of a subtype relationship is the universal type
(e.g. object in pure Python)
while the Bottom is the uninhabited type (e.g. Never).
I swapped the chart representing the possible types.
I also rewrote the following text to use the term
partial order instead of lattice -- using "lattice"
to discuss the subtype relationship seems confusing,
while using "partial order" feels helpful.
I kept the term "lattice" for the diagram of the
state we record about a set of variables though,
because in that context thinking about it as a
lattice seems helpful. I kept Top and Bottom as
they were there -- though honestly I'm not sure
that's right either. It seems the state where
we know nothing about any variable might be called
either Bottom or Top depending on which way you
define the ordering. The state where we have a
specific type assigned to each variable, however,
is not unique, and I'm not sure it should be called
either Top or Bottom. @Fidget-Spinner, thoughts?
After consulting Wikipedia, we realized that the Top of a subtype relationship is the universal type (e.g.
objectin pure Python) while the Bottom is the uninhabited type (e.g.Never).I swapped the chart representing the possible types. I also rewrote the following text to use the term partial order instead of lattice -- using "lattice" to discuss the subtype relationship seems confusing, while using "partial order" feels helpful.
I kept the term "lattice" for the diagram of the state we record about a set of variables though, because in that context thinking about it as a lattice seems helpful. I kept Top and Bottom as they were there -- though honestly I'm not sure that's right either. It seems the state where we know nothing about any variable might be called either Bottom or Top depending on which way you define the ordering. The state where we have a specific type assigned to each variable, however, is not unique, and I'm not sure it should be called either Top or Bottom. @Fidget-Spinner, thoughts?