[1.6.0] Refine features and add dynamic type checkers

[serradura]

Refine the behavior of Kind.of()/Kind.is(), allowing the creation of type checkers dynamically.

Kind.of(User, user) # <User ...>
Kind.of(User, {})   # Kind::Error ({} expected to be a kind of User)

Kind.of(Hash, {})   # {}
Kind.of(Hash, user) # Kind::Error (<User ...> expected to be a kind of Hash)

# ---

kind_of_user = Kind.of(User)

kind_of_user.or_nil({}) # nil

kind_of_user.instance?({})   # false
kind_of_user.instance?(User) # true

kind_of_user.class?(Hash)  # false
kind_of_user.class?(User)  # true

# Create type checkers dynamically is cheap
# because of a singleton object is created to be available for use.

kind_of_user.object_id == Kind.of(User).object_id # true

# --------------------------------------------- #
# Kind.is() can be used to check a class/module #
# --------------------------------------------- #

class Admin < User
end

Kind.is(Admin, User) # true

Adds Kind::Empty

A bunch of frozen values as constants, that could be used as a default value.

• Kind::Empty::SET
• Kind::Empty::HASH
• Kind::Empty::ARRAY
• Kind::Empty::STRING

Improve a lot of other things like: type checker features and optimizations.

Read the readme changes to know them! 😅