ref: cd8fd72bbb8de47f88390db0f13add61da2c90a1
parent: 148a5002cd169e3d3e2142b59e2012a273e52071
author: henesy <henesy.dev@gmail.com>
date: Mon Mar 11 18:02:20 EDT 2019
add beginning of function references example
--- /dev/null
+++ b/Function-Refs/README.md
@@ -1,0 +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?
--- /dev/null
+++ b/Function-Refs/funcrefs.b
@@ -1,0 +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");+}