Add example links in README.md

1 files changed, 4 insertions, 74 deletions

diff --git a/README.md b/README.md
index d0cd6f3..9dadc45 100644
--- a/README.md
+++ b/README.md
@@ -29,79 +29,9 @@ $ chicken-install
 - Alternative
   - list
 
-## Example: `Optional` monad
+## Example
 
-```
-(module (data optional) (<some> some some? some-value <none> none none?)
-  (import scheme (chicken base) (chicken format))
-
-  (define-record-type <some>
-    (some value)
-    some?
-    (value some-value))
-
-  (set! (record-printer <some>)
-    (lambda (x out)
-      (fprintf out "#<(some ~S)>" (some-value x))))
-
-  (define-record-type <none>
-    (none)
-    none?)
-
-  (set! (record-printer <none>)
-    (lambda (_ out)
-      (fprintf out "#<(none)>"))))
-
-(module (data optional monad base) (pure map map2 >>=)
-  (import (except scheme map)
-          (prefix (data optional) opt:)
-          matchable)
-
-  (define (map f opt)
-    (match opt
-      [($ opt:<some> x) (opt:some (f x))]
-      [($ opt:<none>) (opt:none)]))
-
-  (define (pure x)
-    (opt:some x))
-
-  (define (map2 f opt1 opt2)
-    (match opt1
-      [($ opt:<some> x)
-       (match opt2
-         [($ opt:<some> y) (opt:some (f x y))]
-         [($ opt:<none>) (opt:none)])]
-      [($ opt:<none>) (opt:none)]))
-
-  (define (>>= opt f)
-    (match opt
-      [($ opt:<some> x) (f x)]
-      [($ opt:<none>) (opt:none)])))
-
-(import (only (algebraic-structs functor make)))
-(import (only (algebraic-structs applicative make)))
-(import (only (algebraic-structs monad make)))
-(module (data optional functor) = ((algebraic-structs functor make) (data optional monad base)))
-(module (data optional applicative) = ((algebraic-structs applicative make) (data optional monad base)))
-(module (data optional monad) = ((algebraic-structs monad make) (data optional monad base)))
-
-(import (prefix (data optional) opt:)
-        (prefix (data optional functor) opt:)
-        (prefix (data optional applicative) opt:)
-        (prefix (data optional monad) opt:))
-
-;; (opt:map (lambda (x) (* x x)) (opt:pure 5)) => (some 25)
-;; (opt:map (lambda (x) (* x x)) (opt:none)) => (none)
-
-;; (opt:map* + (opt:pure 1) (opt:pure 2) (opt:pure 3)) => (some 6)
-;; (opt:map* + (opt:pure 1) (opt:none) (opt:pure 3)) => (none)
-
-;; (opt:do (x <- (opt:pure 3))
-;;         (y <- (opt:pure 4))
-;;         (opt:pure (+ x y)))
-;; => (some 7)
-```
-
-## LICENSE
+- Monad
+  - [optonal](./examples/optional.scm)
+  - [state](./examples/optional.scm)
 
-This program is licensed under the MIT License. See the LICENSE file for details.