Adds an example file

examples/canvas/colors-and-lines.slo

@@ -0,0 +1,24 @@
+(define size 1)
+(define color 1)
+(define colordir 1)
+(define sizedir 1)
+(define tick 1)
+
+(set! draw
+  (lambda ()
+    (set! tick (+ tick 1))
+    (circle (/ screen-width 2) (/ screen-height 2) size color)
+    (set! size (rand-range-int 1 screen-width))
+    (line
+      (rand-range-int 0 screen-width) (rand-range-int 0 screen-height)
+      (rand-range-int 0 screen-width) (rand-range-int 0 screen-height)
+      (rand-range-int 1 4))
+    (if
+      (equal?
+        (% tick 8) 0)
+      (begin
+        (set! color (+ color colordir))    
+        (if (or (equal? color 4) (equal? color 1))
+          (set! colordir (- colordir)))))))
+
+(run)

libs/math.js

@@ -141,5 +141,22 @@ var slopeMathLib = {
     return Math.round(nums[0]);
   },
   "rand": Math.random,
-
+  "rand-range": function(...nums) {
+    if (!nums.length) {
+      throw new Error("'rand-range' expects at least one number (representing the top of the range with 0 as a start point) or two numbers (representing the bottom and top of the range)");
+    }
+    if (nums.length == 1) {
+      return Math.random() * nums[0];
+    }
+    return Math.random() * (nums[1] - nums[0] + 1) + nums[1]
+  },
+  "rand-range-int": function(...nums) {
+    if (!nums.length) {
+      throw new Error("'rand-range-int' expects at least one number (representing the top of the range with 0 as a start point) or two numbers (representing the bottom and top of the range)");
+    }
+    if (nums.length == 1) {
+      return Math.floor(Math.random() * nums[0]);
+    }
+    return Math.floor(Math.random() * (nums[1] - nums[0] + 1) + nums[0]);
+  }
 }