--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/3-Prolog/day1-wallaceandgrommit.pl	Mon Sep 25 20:49:52 2017 +0100
@@ -0,0 +1,16 @@
+% Start with some simple facts
+% Note: like semantic systems, names are intrinsicly equal variables
+% (or variables don't exist). Names are called "atoms"
+likes(wallace, cheese).
+likes(grommit, cheese).
+likes(wendolene, sheep).
+% Each statement ends with a fullstop
+
+% Rule syntax is a bit odd (":-" and "\+") but we're saying that X and Y
+% can be friends if X and Y like the same thing.
+% Poor Wendolene.
+friend(X, Y) :- \+(X = Y), likes(X, Z), likes(Y, Z).
+% "\+" is apparently logical negation (because of course it is)
+% so the first "subgoal" stops Wallace being Wallace's friend
+%
+% Note: Prolog nomenclature is that this is "friend/2" - friend func with 2 params
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