1 files changed, 28 insertions, 4 deletions
diff --git a/terrafirma.lisp b/terrafirma.lisp
index 78d74c9..b5ef90c 100644
--- a/terrafirma.lisp
+++ b/terrafirma.lisp
@@ -3,8 +3,10 @@
 (defpackage #:terrafirma
   (:use #:cl)
   (:export
-   #:validate
-   #:defvalidator))
+   #:validation-error                   ; Condition
+   #:validate                           ; Macrolet Symbol
+   #:defvalidator                       ; Macro
+   ))
 
 (in-package #:terrafirma)
 
@@ -47,10 +49,31 @@
 (defvar *instance*)
 
 (defmacro defvalidator ((var type &key name) &body body)
+  "Defines a validation function. If TYPE is a symbolic type identifier,
+then the defined function will have a name like VALID-<TYPE>-P.
+Otherwise a NAME must be provided. 
+
+This means you can define validators for types like (CONS CHAR) if you
+want.
+
+Within the body of DEFVALIDATOR, a special VALIDATE macro is
+bound. Its syntax is:
+
+(VALIDATE CHECK FORMATSTRING &REST FORMATARGS)
+
+E.G. 
+
+    (validate (= 10 foo) \"Foo = ~s is not equal to 10\" foo)
+
+A VALIDATE form returns T if CHECK evaluates to non-nil. If CHECK
+signals an error, or if CHECK returns NIL, then the whole validator
+fails.
+
+If all VALIDATE forms pass, then the function returns T."
   (assert (and var (symbolp var)) (var) "VAR must be a symbol.")
   (let ((validator-name
           (cond ((and name (symbolp name)) name)
-                ((symbolp type) (intern (format nil "VALIDATED-~a" type)))
+                ((symbolp type) (intern (format nil "VALID-~a-P" type)))
                 (t (error "Validator Name: Either TYPE must be a symbol or a NAME must be provided.")))))
     `(macrolet ((validate (check msg &rest args)
                     (let ((suberr (gensym)))
@@ -65,4 +88,5 @@
        (defun ,validator-name (,var)
          (let ((terrafirma::*type* ',type)
                (terrafirma::*instance* ,var))
-           ,@body)))))
+           ,@body
+           t)))))