From a4a7edd487d4d2207829462d06c40578dc757337 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=B6rnquist?= <hugo@lysator.liu.se>
Date: Thu, 14 Mar 2019 20:08:58 +0100
Subject: Generilified return, monads now truly functors.

---
 data/functor.scm  | 19 -------------------
 data/optional.scm | 28 +++++++---------------------
 2 files changed, 7 insertions(+), 40 deletions(-)
 delete mode 100644 data/functor.scm

(limited to 'data')

diff --git a/data/functor.scm b/data/functor.scm
deleted file mode 100644
index 4e4722f..0000000
--- a/data/functor.scm
+++ /dev/null
@@ -1,19 +0,0 @@
-(define-module (data functor)
-  #:use-module (oop goops)
-  #:use-module (srfi srfi-1)
-  #:use-module (ice-9 curried-definitions)
-  #:export (fmap <$> cmap))
-
-;;; We don't overwrite the default map since that creates way to many
-;;; namespace problems.
-
-(define-generic fmap)
-(define <$> fmap)
-
-;;; Default fallback for fmap is regular (srfi-1) map.
-(define-method (fmap f . lists)
-  (apply map f lists))
-
-;; Curried map
-(define ((cmap f) item)
-  (fmap f item))
diff --git a/data/optional.scm b/data/optional.scm
index 7ab944c..61543d2 100644
--- a/data/optional.scm
+++ b/data/optional.scm
@@ -2,18 +2,16 @@
   #:use-module (oop goops)
   #:use-module (ice-9 match)
   #:use-module (control monad)
-  #:use-module (data functor)
   #:use-module (ice-9 curried-definitions)
-  #:export (nothing just
-                    nothing? just?
-                    from-just wrap-maybe
-                    return-optional)
-  #:re-export (>>= >> fmap))
+  #:export (from-just wrap-maybe
+                      nothing just
+                      nothing? just?)
+  #:re-export (>>= >> return))
 
 (define-class <optional> ()
   (slot #:init-value #f
         #:init-keyword #:slot)
-  (just  #:init-value #t
+  (just #:init-value #t
         #:init-keyword #:just))
 
 (define (nothing) (make <optional> #:just #f))
@@ -45,23 +43,11 @@ the value embedded in maybe-val"
       (format port "[Just ~s]" (slot-ref this 'slot))
       (format port "[Nothing]")))
 
-(define return-optional just)
-
 (define-method (>>= (this <optional>)
                     (proc <procedure>))
   (cond ((nothing? this) (nothing))
-        ((just? this) 
+        ((just? this)
          (match this
            (($ <optional> slot) (proc slot))))))
 
-(define-method (>> (a <optional>)
-                   (b <optional>))
-  (if (or (nothing? a)
-          (nothing? b))
-      (nothing)
-      b))
-
-(define-method (fmap (f <procedure>)
-                     (m <optional>))
-  (do x <- m
-      (return-optional (f x))))
+(define-method (return (a <optional>)) just)
-- 
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