diff --git a/content/cftbat/writing-macros.html b/content/cftbat/writing-macros.html index 469dbac2..94474ebb 100644 --- a/content/cftbat/writing-macros.html +++ b/content/cftbat/writing-macros.html @@ -519,7 +519,7 @@

Validation Functions

(partition 2 message-validator-pairs)))) -

The first argument, to-validate, is the field you want to validate. The second argument, message-validator-pairs, should be a seq with an even number of elements. This seq gets grouped into pairs with (partition 2 message-validator-pairs). The first element of the pair should be an error message, and the second element of the pair should be a function (just like the pairs are arranged in order-details-validation). The error-messages-for function works by filtering out all error message and validation pairs where the validation function returns true when applied to to-validate. It then uses map first to get the first element of each pair, the error message. Here it is in action:

+

The first argument, to-validate, is the field you want to validate. The second argument, message-validator-pairs, should be a seq with an even number of elements. This seq gets grouped into pairs with (partition 2 message-validator-pairs). The first element of the pair should be an error message, and the second element of the pair should be a function (just like the pairs are arranged in order-details-validations). The error-messages-for function works by filtering out all error message and validation pairs where the validation function returns true when applied to to-validate. It then uses map first to get the first element of each pair, the error message. Here it is in action:

(error-messages-for "" ["Please enter a name" not-empty])
 ; => ("Please enter a name")
@@ -569,7 +569,7 @@

if-valid

However, this wouldn’t work, because success-code and failure-code would get evaluated each time. A macro would work because macros let you control evaluation. Here’s how you’d use the macro:

- 
(if-valid order-details order-details-validation errors
+	
(if-valid order-details order-details-validations errors
  (render :success)
  (render :failure errors))
 

@@ -604,7 +604,7 @@ 
Summary

 	
Exercises

 	
    
 	  
  1. Write the macro when-valid so that it behaves similarly to when. Here is an example of calling it: 
-	
    (when-valid order-details order-details-validation
+	
    (when-valid order-details order-details-validations
  (println "It's a success!")
  (render :success))