From c91e15f6e1597aa96fc5072c2e927f7c39edf124 Mon Sep 17 00:00:00 2001
From: Ben Culkin <scorpress@gmail.com>
Date: Sat, 21 Nov 2020 16:51:29 -0500
Subject: Add a 'functional' FizzBuzz example

---
 .../bjc/utils/examples/FunctionalFizzBuzz.java     | 71 ++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 base/src/examples/java/bjc/utils/examples/FunctionalFizzBuzz.java

diff --git a/base/src/examples/java/bjc/utils/examples/FunctionalFizzBuzz.java b/base/src/examples/java/bjc/utils/examples/FunctionalFizzBuzz.java
new file mode 100644
index 0000000..08551c7
--- /dev/null
+++ b/base/src/examples/java/bjc/utils/examples/FunctionalFizzBuzz.java
@@ -0,0 +1,71 @@
+package bjc.utils.examples;
+
+import java.util.function.*;
+import bjc.data.*;
+
+import static bjc.functypes.Combinators.*;
+
+/**
+ * @author Ben Culkin
+ *
+ */
+public class FunctionalFizzBuzz {	
+	interface FizzBuzzFunc 
+		extends Function<UnaryOperator<String>, UnaryOperator<String>> {
+		// Alias type
+	}
+	
+	/**
+	 * Calculate fizz-buzz in an un-functional functional way.
+	 * 
+	 * @param args Ignored CLI args
+	 */
+	public static void main(String[] args) {
+		// Do something, at some point
+		times(
+				100,
+				andThen(
+  				invoke(
+      			introducing(
+      					() -> new IntHolder(),
+      					(holder, arg) -> {			
+      							Consumer<Integer>   numSetter2 = (num) -> holder.set(num);        		
+      							
+      							return (num) -> beforeThis(
+      									numSetter2,
+      									compose(
+      											input  -> Integer.toString(input),
+      											strang -> 
+      													fbMaker(3, "Fizz", "", holder)
+      														.apply(
+      															fbMaker(5, "Buzz", "", holder)
+      																.apply(ignore -> ignore)
+      														)
+      														.apply(strang)
+      									)
+      							).apply(num);
+      					}
+      			)
+      		),
+  				System.out::println
+  			)
+		);
+	}
+	
+	private static FizzBuzzFunc fbMaker(
+			int cond, String initial, String interleave, IntHolder var) {
+		return func -> invoke(
+				iftt(
+						ignored1 -> var.get() % cond == 0,
+						arg      -> initial + func.apply(interleave),
+						func
+				)
+		);
+	}
+	
+	private static <Input, Output> Function<Input, Output> iftt(Predicate<Input> in,
+			Output ifTrue,
+			Output ifFalse) {
+		return (arg) -> in.test(arg) ? ifTrue : ifFalse;
+	}
+}
\ No newline at end of file
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