Remove redundant AST.
Support Parser for package statement.
Implement foldAST for the PerlPackage data constructor.
Support function definition in packages
Abstraction
Make TypeObj having method lists
Implementing method calls.
Rename
Oops. I do the trivial mistake.
Add recursive type support.
Allow records to define recursively
Fix composition orders.
Fix a test
Avoid infinite recursions
Add dump codes for debugging
Fix composition of substitution.
Check equalities of recursive types seriously.