# HG changeset patch
# User IBBoard <dev@ibboard.co.uk>
# Date 1504722560 -3600
# Node ID 3d41d9d72cc916463e1fcb85e30d82491f3d2775
# Parent  4e1a659f83830935e2830235b282a3b419f3eb6e
Add Day 1 code for Singletons (including booleans)

diff -r 4e1a659f8383 -r 3d41d9d72cc9 2-Io/day1-singletons.io
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/2-Io/day1-singletons.io	Wed Sep 06 19:29:20 2017 +0100
@@ -0,0 +1,36 @@
+# Conditions are simple and like most languages
+# Not mentioned yet, but found by necessity: we can use brackets!
+(4 < 5) println
+# Unlike Python, Io uses lower case for booleans
+(true and false) println
+# Truthy values are more like Python than C:
+(true and 6) println
+(true and 0) println
+
+# But true, false and nil are all just objects
+# Albeit special "singleton" objects where cloning gets the same object
+true clone println
+false clone println
+nil clone println
+(true == true clone) println
+
+# We can create our own singletons by altering the clone method to return the class
+# Highlander: THERE CAN BE ONLY ONE!
+Highlander := Object clone
+Highlander clone := Highlander
+Highlander println
+Highlander clone println
+highlander1 := Highlander clone
+highlander2 := Highlander clone
+(highlander1 == highlander2) println
+# Normally cloning gives different objects with different IDs
+obj1 := Object clone
+obj2 := Object clone
+(obj1 == obj2) println
+
+# And with great power comes great responsibility.
+# Object is not special. It is not protected in any way.
+# DO NOT do this in real code!
+Object clone := "Ooops!"
+obj3 := Object clone
+obj3 println
\ No newline at end of file