Update Constant instruction.
Add assign_types module (work in progress).
Make the parentheses optional in an array type.

(And require the element type.)
Add class and array summaries.
Add vector type summaries.
Add task summaries.
Add tuple summaries.
Add function summaries.
Refactor class and function summaries.
Raise exception in exceptional case.
Use recursive function to assign types (work in progress).