Givens / Anonymous Implicit Parameters / Ambient Values

[AshleyYakeley]

Refs

• https://rockthejvm.com/articles/scala-3-givens-vs-implicits

Uses

Ambient equivalences

like Haskell class instances.

Storablility

type Storability t
    LiteralStorability
        t -> Literal
        Literal -> Maybe t
    MkStorability
        t -> Entity

property: Storability a => Storability b => Anchor -> Store -> Property a b

Design

Gives are when givens are provided. Takes are when givens are used.

1. Lexical scope. Given must be in scope of take.

• can import gives
• cannot import takes (?)
• let {?a = 1} let {x = ?a} x => =1
• let {x = ?a} let {?a = 1} x => unimplied ?a

2. Scope like implicit parameters.

• Ends up in type signature
• cannot import gives
• can import takes
• take: a => a
• imply {?a = 1} let {x = ?a} x (non-lexical scope) =1
• let {x = ?a} imply {?a = 1} x (non-lexical scope) =1