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agda-spa/lean/Spa/Showable.lean

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/-
Port of `Showable.agda` (plus the `Showable` instances that lived on
`Lattice/Map.agda` and `Lattice/AboveBelow.agda`).
Lean has `ToString`, but its `String` instance does not quote (the Agda one
does), so to reproduce the Agda output exactly we port the class as-is.
-/
import Spa.Lattice.FiniteMap
import Spa.Lattice.AboveBelow
namespace Spa
/-- Agda: `Showable` (`show` is a Lean keyword, hence `show'`). -/
class Showable (α : Type*) where
show' : α String
export Showable (show')
instance : Showable String := fun s => "\"" ++ s ++ "\""
instance : Showable := toString
instance : Showable := toString
instance {n : } : Showable (Fin n) := fun i => toString i.val
instance {α β : Type*} [Showable α] [Showable β] : Showable (α × β) :=
fun p => "(" ++ show' p.1 ++ ", " ++ show' p.2 ++ ")"
instance : Showable PUnit := fun _ => "()"
/-- Agda: the `Showable` instance of `Lattice/AboveBelow.agda`. -/
instance {α : Type*} [Showable α] : Showable (AboveBelow α) :=
fun
| .bot => ""
| .top => ""
| .mk x => show' x
/-- Agda: the `Showable` instance of `Lattice/Map.agda` (inherited by
`FiniteMap`). -/
instance {α β : Type*} {ks : List α} [Showable α] [Showable β] :
Showable (FiniteMap α β ks) :=
fun fm =>
"{" ++ fm.val.foldr (fun p rest => show' p.1 ++ "" ++ show' p.2 ++ ", " ++ rest) ""
++ "}"
end Spa