From cb667b462abeb83be91000922efbc71086dd0c00 Mon Sep 17 00:00:00 2001
From: David Chambers <dc@davidchambers.me>
Date: Thu, 16 Jan 2020 02:18:47 +0100
Subject: [PATCH] maybe, either: remove S.maybeToEither and S.eitherToMaybe

---
 index.js              | 50 +++----------------------------------------
 test/eitherToMaybe.js | 15 -------------
 test/maybeToEither.js | 15 -------------
 3 files changed, 3 insertions(+), 77 deletions(-)
 delete mode 100644 test/eitherToMaybe.js
 delete mode 100644 test/maybeToEither.js

diff --git a/index.js b/index.js
index d7b110a4..2b761293 100644
--- a/index.js
+++ b/index.js
@@ -2227,29 +2227,6 @@
     impl: maybeToNullable
   };
 
-  //# maybeToEither :: a -> Maybe b -> Either a b
-  //.
-  //. Converts a Maybe to an Either. Nothing becomes a Left (containing the
-  //. first argument); a Just becomes a Right.
-  //.
-  //. See also [`eitherToMaybe`](#eitherToMaybe).
-  //.
-  //. ```javascript
-  //. > S.maybeToEither ('Expecting an integer') (S.parseInt (10) ('xyz'))
-  //. Left ('Expecting an integer')
-  //.
-  //. > S.maybeToEither ('Expecting an integer') (S.parseInt (10) ('42'))
-  //. Right (42)
-  //. ```
-  function maybeToEither(x) {
-    return maybe (Left (x)) (Right);
-  }
-  _.maybeToEither = {
-    consts: {},
-    types: [a, $.Maybe (b), $.Either (a) (b)],
-    impl: maybeToEither
-  };
-
   //. ### Either
   //.
   //. The Either type represents values with two possibilities: a value of type
@@ -2510,29 +2487,6 @@
     impl: encase
   };
 
-  //# eitherToMaybe :: Either a b -> Maybe b
-  //.
-  //. Converts an Either to a Maybe. A Left becomes Nothing; a Right becomes
-  //. a Just.
-  //.
-  //. See also [`maybeToEither`](#maybeToEither).
-  //.
-  //. ```javascript
-  //. > S.eitherToMaybe (S.Left ('Cannot divide by zero'))
-  //. Nothing
-  //.
-  //. > S.eitherToMaybe (S.Right (42))
-  //. Just (42)
-  //. ```
-  function eitherToMaybe(either) {
-    return either.isLeft ? Nothing : Just (either.value);
-  }
-  _.eitherToMaybe = {
-    consts: {},
-    types: [$.Either (a) (b), $.Maybe (b)],
-    impl: eitherToMaybe
-  };
-
   //. ### Logic
 
   //# and :: Boolean -> Boolean -> Boolean
@@ -4376,7 +4330,9 @@
   //. Just ([1, 2, 3])
   //. ```
   function parseJson(pred) {
-    return B (filter (pred)) (B (eitherToMaybe) (encase (JSON.parse)));
+    return B (filter (pred))
+             (B (either (K (Nothing)) (Just))
+                (encase (JSON.parse)));
   }
   _.parseJson = {
     consts: {},
diff --git a/test/eitherToMaybe.js b/test/eitherToMaybe.js
deleted file mode 100644
index 7d61bbff..00000000
--- a/test/eitherToMaybe.js
+++ /dev/null
@@ -1,15 +0,0 @@
-'use strict';
-
-const S = require ('..');
-
-const eq = require ('./internal/eq');
-
-
-test ('eitherToMaybe', () => {
-
-  eq (S.show (S.eitherToMaybe)) ('eitherToMaybe :: Either a b -> Maybe b');
-
-  eq (S.eitherToMaybe (S.Left ('Cannot divide by zero'))) (S.Nothing);
-  eq (S.eitherToMaybe (S.Right (42))) (S.Just (42));
-
-});
diff --git a/test/maybeToEither.js b/test/maybeToEither.js
deleted file mode 100644
index 0f64a8af..00000000
--- a/test/maybeToEither.js
+++ /dev/null
@@ -1,15 +0,0 @@
-'use strict';
-
-const S = require ('..');
-
-const eq = require ('./internal/eq');
-
-
-test ('maybeToEither', () => {
-
-  eq (S.show (S.maybeToEither)) ('maybeToEither :: a -> Maybe b -> Either a b');
-
-  eq (S.maybeToEither ('error msg') (S.Nothing)) (S.Left ('error msg'));
-  eq (S.maybeToEither ('error msg') (S.Just (42))) (S.Right (42));
-
-});