:= -package:grisette

Construct a field, fieldname := value.
Assign a value to an attribute.
Assign a value to an attribute
A type represents the top-level named key argument.
Field named l labels value of type t. Example: (#name := "Chris") :: ("name" := String)
Trivial Rewrite
Leibnizian equality states that two things are equal if you can substitute one for the other in all contexts
Add annotations to a field.
Reify the relationship between an instance head and its body as a class Given a definition such as
instance Foo a => Foo [a]
you can capture the relationship between the instance head and its body with
instance Foo a :=> Foo [a] where ins = Sub Dict