From dd3db073db4f5324f802bc69855f96225668de19 Mon Sep 17 00:00:00 2001
From: Hammy <sgoudham@gmail.com>
Date: Mon, 5 Apr 2021 00:28:22 +0100
Subject: [PATCH] Implement custom sorting methods

---
 Unit 1/Lesson 4/AllNames.hs      |  8 ++++++++
 Unit 1/Lesson 4/customSorting.hs | 22 ++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 Unit 1/Lesson 4/AllNames.hs
 create mode 100644 Unit 1/Lesson 4/customSorting.hs

diff --git a/Unit 1/Lesson 4/AllNames.hs b/Unit 1/Lesson 4/AllNames.hs
new file mode 100644
index 0000000..181fdcc
--- /dev/null
+++ b/Unit 1/Lesson 4/AllNames.hs	
@@ -0,0 +1,8 @@
+module AllNames where
+
+names :: [([Char], [Char])]
+names = [("Callum", "Kilmartin"),
+         ("Goudham","Suresh"),
+         ("Theo", "Hardman"),
+         ("Luca","Valentini"),
+         ("Cormac", "Muir")]
\ No newline at end of file
diff --git a/Unit 1/Lesson 4/customSorting.hs b/Unit 1/Lesson 4/customSorting.hs
new file mode 100644
index 0000000..206a6b8
--- /dev/null
+++ b/Unit 1/Lesson 4/customSorting.hs	
@@ -0,0 +1,22 @@
+import Data.List (sort, sortBy)
+import AllNames (names)
+
+compareLastNames :: Ord a1 => (a2, a1) -> (a3, a1) -> Ordering
+compareLastNames name1 name2 = if surname1 > surname2
+                               then GT
+                               else if surname1 < surname2
+                                    then LT
+                                    else EQ
+  where surname1 = snd name1
+        surname2 = snd name2
+
+-- Using Guards for boolean expressions
+
+-- compareLastNames :: Ord a1 => (a2, a1) -> (a3, a1) -> Ordering
+-- compareLastNames name1 name2
+--   | surname1 > surname2 = GT
+--   | surname1 < surname2 = LT
+--   | otherwise = EQ
+--   where
+--       surname1 = snd name1
+--       surname2 = snd name2
\ No newline at end of file