30 lines
655 B
Text
30 lines
655 B
Text
new_frontend
|
||
|
||
class HasElems (α : Type) : Type := (elems : Array α)
|
||
def elems (α : Type) [HasElems α] : Array α := HasElems.elems
|
||
|
||
inductive Foo : Type
|
||
| mk1 : Bool → Foo
|
||
| mk2 : Bool → Foo
|
||
|
||
open Foo
|
||
|
||
instance BoolElems : HasElems Bool := ⟨#[false, true]⟩
|
||
instance FooElems : HasElems Foo := ⟨(elems Bool).map mk1 ++ (elems Bool).map mk2⟩
|
||
|
||
def fooRepr (foo : Foo) :=
|
||
match foo with
|
||
| mk1 b => s!"OH {b}"
|
||
| mk2 b => s!"DR {b}"
|
||
|
||
instance : HasRepr Foo := ⟨fooRepr⟩
|
||
|
||
#eval elems Foo
|
||
|
||
#eval #[false, true].map Foo.mk1
|
||
|
||
def Foo.toBool : Foo → Bool
|
||
| Foo.mk1 b => b
|
||
| Foo.mk2 b => b
|
||
|
||
#eval #[Foo.mk1 false, Foo.mk2 true].map Foo.toBool
|