Add TypeVar constants representing the available type functions, and a
TypeVar.derived() static method which creates a derived TypeVar.
Keep the existing non-parametric methods for creating derived type
variables.
Add a method for converting a free type variable to a derived one.
A few operands have a fixed type assigned. Create a singleton type
variable for these exceptions. Most instructions are polymorphic, so
this is a little overhead.
Eliminate the Operand.typ field and replace it with an Operand.typevar
field which is always a TypeVar, but which only exists in VALUE
operands.
This method caused lots of import cycles when type checking.
Use isinstance() in the Operand constructor instead to decipher the
OperandSpec union type.
We want to separate the Python classes that make up the DSL used to
define the Cretonne language from the concrete definitions.
- cdsl.types defines the ValueType class hierarchy.
- base.types defines the concrete types.
