module system

[mizunashi-mana]

• hierarchical module
• internal module
• module alias

import Data.Text as Text

is an alias of

import Data.Text
module Text = Data.Text

[mizunashi-mana]

• nominal subtyping and structural type checking
• support inheritance

record C1 a = {
  method1: a -> a,
}
module A1: C1 Int begin
  method1: Int -> Int
  method1 x = x
end

record C2 a = {
  method2: a -> a
} with (
  C1 a,
)
module A2
with A1
begin
  method2 x = method1 x
end

[mizunashi-mana]

type family may be replaced by first class (higher-order) module