From 961e9ae7d76a068017d079b0b08847d3284c8336 Mon Sep 17 00:00:00 2001
From: Rob Rix <rob.rix@github.com>
Date: Wed, 14 Oct 2015 10:39:01 -0400
Subject: [PATCH] Implement coiteration.

---
 prototype/Doubt/Cofree.swift | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/prototype/Doubt/Cofree.swift b/prototype/Doubt/Cofree.swift
index e875dfad9..e774e8a46 100644
--- a/prototype/Doubt/Cofree.swift
+++ b/prototype/Doubt/Cofree.swift
@@ -14,6 +14,11 @@ public enum Cofree<A, B> {
 			return rest
 		}
 	}
+
+
+	public static func coiterate(annotate: B -> Syntax<B, A>)(_ seed: B) -> Cofree {
+		return .Unroll(seed, annotate(seed).map(coiterate(annotate)))
+	}
 }