Created
December 12, 2010 19:14
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A variant on Conor McBride's trick
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-- Forked from http://personal.cis.strath.ac.uk/~conor/fooling/Jigger.agda | |
module Jigger where | |
data Nat : Set where | |
zero : Nat | |
suc : Nat -> Nat | |
_+_ : Nat -> Nat -> Nat | |
zero + n = n | |
suc m + n = suc (m + n) | |
data Fin : Nat -> Set where | |
zero : {n : Nat} -> Fin (suc n) | |
suc : {n : Nat} -> Fin n -> Fin (suc n) | |
max : {n : Nat} -> Fin (suc n) | |
max {zero} = zero | |
max {suc n} = suc (max {n}) | |
embed : {n : Nat} -> Fin n -> Fin (suc n) | |
embed zero = zero | |
embed (suc n) = suc (embed n) | |
var : (m : Nat){n : Nat} -> Fin (suc (m + n)) | |
var zero = max | |
var (suc m) = embed (var m) | |
infixl 50 _$_ | |
data Tm (n : Nat) : Set where | |
V : Fin n -> Tm n | |
_$_ : Tm n -> Tm n -> Tm n | |
L : Tm (suc n) -> Tm n | |
l : {m : Nat} -> (({n : Nat} -> Tm (suc (m + n))) -> Tm (suc m)) -> | |
Tm m | |
l {m} f = L (f \{n} -> V (var m {n})) | |
infixr 40 l | |
-- Define new syntax for l | |
syntax l (λ x → e) = Λ x ↦ e | |
myTest : Tm zero | |
myTest = Λ f ↦ Λ x ↦ f $ (f $ x) |
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