From cd8fd72bbb8de47f88390db0f13add61da2c90a1 Mon Sep 17 00:00:00 2001
From: henesy <henesy.dev@gmail.com>
Date: Mon, 11 Mar 2019 22:02:20 -0500
Subject: add beginning of function references example

---
 Function-Refs/README.md  |  19 +++++++++
 Function-Refs/funcrefs.b | 105 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 Function-Refs/README.md
 create mode 100644 Function-Refs/funcrefs.b

diff --git a/Function-Refs/README.md b/Function-Refs/README.md
new file mode 100644
index 0000000..09a6715
--- /dev/null
+++ b/Function-Refs/README.md
@@ -0,0 +1,19 @@
+# Function References
+
+Limbo supports references to functions, similar to closures, but more similar to function pointers. 
+
+The example in this section is a derivative of the function reference summary in the [Limbo Addendum](http://www.vitanuova.com/inferno/papers/addendum.pdf). 
+
+## Source
+
+### 
+
+
+
+## Demo
+
+
+
+## Exercises
+
+- Change the value of `c` to 1, what happens?
diff --git a/Function-Refs/funcrefs.b b/Function-Refs/funcrefs.b
new file mode 100644
index 0000000..d4b7259
--- /dev/null
+++ b/Function-Refs/funcrefs.b
@@ -0,0 +1,105 @@
+implement FuncRefs;
+
+include "sys.m";
+include "draw.m";
+
+sys: Sys;
+print: import sys;
+
+FuncRefs: module {
+	init: fn(nil: ref Draw->Context, nil: list of string);
+};
+
+Cmp: type ref fn(s1: string, s2: string): int;
+
+init(nil: ref Draw->Context, nil: list of string) {
+	sys = load Sys Sys->PATH;
+
+	fp: ref fn(s1: string, s2: string): int;
+
+	fp = cmp;
+
+	a := fp("☺", ":)");
+
+	if(a)
+		print("Matched smiley!\n");
+	else
+		print("Did not match smiley\n");
+
+	b := fp("duck", "duck");
+
+	if(b)
+		print("Matched duck!\n");
+	else
+		print("Did not match duck\n");
+
+	unsorted := array[4] of {"d", "b", "c", "a"};
+
+	printarr(unsorted);
+
+	carr := sort(unsorted, cmp);
+
+	printarr(carr);
+
+	rarr := sort(unsorted, rcmp);
+
+	printarr(rarr);
+
+	c := 0;
+
+	if(choose(c)("quack", "quack") <= 0)
+		print("quack ≤ quack\n");
+	else
+		print("quack > quack\n");
+
+	exit;
+}
+
+cmp(s1: string, s2: string): int {
+	if(s1 < s2)
+		return -1;
+
+	if(s1 > s2)
+		return 1;
+
+	return 0;
+}
+
+rcmp(s1: string, s2: string): int {
+	return -cmp(s1, s2);
+}
+
+choose(i: int): Cmp {
+	if(i)
+		return rcmp;
+
+	return cmp;
+}
+
+# Insertion sort
+sort(arr: array of string, comp: ref fn(s1, s2: string): int): array of string {
+	i, j: int;
+	key: string;
+	n := len arr;
+
+	for(i = 1; i < n; i++) {
+		key = arr[i];
+		j = i-1;
+
+		while(j >= 0 && comp(arr[j], key) > 0) { 
+			arr[j+1] = arr[j];
+			j = j-1;
+		}
+
+		arr[j+1] = key;
+	}
+
+	return arr;
+}
+
+printarr(arr: array of string) {
+	print("[");
+	for(i := 0; i < len arr; i++)
+		print(" %s", arr[i]);
+	print("]\n");
+}
-- 
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