add bool to checkbox convertion funcitons to utils pacakge.

The functions are helper functions for when dealing with
SQLite3. Because SQLite3 doesn't have a Boolean data-type, I have to
store the 'true' and 'false' values as integetes.

0 == false
1 == true.

src/utils.lisp

@@ -2,7 +2,8 @@
 (defpackage #:utils
   (:use #:cl
 	#:caveman2
-	#:log4cl)
+	#:log4cl
+	#:app-constants)
   (:export #:i18n-load
            #:_
            #:parse-iso-date
@@ -11,7 +12,9 @@
 	   #:separate-files-in-web-request
 	   #:set-alert
 	   #:get-alert
-	   #:get-and-reset-alert)
+	   #:get-and-reset-alert
+	   #:bool-to-checkbox
+	   #:checkbox-to-bool)
   (:documentation "Utilities that do not depend on models."))
 
 (in-package #:utils)
@@ -62,3 +65,22 @@ POST request."
   (let ((message (get-alert)))
     (set-alert nil)
     message))
+
+(defun bool-to-checkbox (value)
+  "Converts `VALUE' so it can populate an HTML checkbox.
+It is assumed you are converting a SQLite version of a Boolean so
+either 1 (true) or 0 (false). If you need a traditional Boolean value,
+DO NOT USE THIS FUNCTION."
+  (cond ((= value 0) "off")
+	((null value) "off")
+	(t "on")))
+
+(defun checkbox-to-bool (value)
+  "Converts a HTML Checkbox `VALUE' to a Boolean.
+The `VALUE' will either be 'on' or 'off'. 'Boolean' in this instance
+is assuming you are using SQLite and need to convert `VALUE' to an
+integer/number. If you are needing a traditional Boolean value, DO NOT USE
+THIS FUNCTION."
+  (cond ((string= "checked" value) +true+)
+	((string= "off" value) +false+)
+	((null value) +false+)))