implement cast expression
Make typeof be a regular method
Add boolean as a Myrial type
Create a registry of primitive types
Make schema required for Empty expression
Use canonical type names for Empty tables
Change type names in myria catalog
convert datalog tests to official types
Use official type names in setop_tests
Use canonical type names in datalog
Fix typeof for literals
Add typeof for attribute references
Add typeof for state refs
Add typeof for case, binary operations
Add typeof for boolean operators
Add typeof for functions
Add typeof for aggregates
Consolidate code for attribute references
fix join example
Fix typo