MMValidation is a category on NSObject that gives you validation functionality similar to the declarative style of Ruby on Rails.  

MMValidation is freely distributable under the terms of the MIT license.

INSTALLATION

To install in your project, simply copy the following files into your project:

- MMValidation.h
- MMValidation.m
- MMValidationError.h
- MMValidationError.m
- NSObject+MMValidation.h
- NSObject+MMValidation.m

USAGE

First, import MMValidation in the class you want to validate:

#import "NSObject+MMValidation.h"

Then, override the +(void)initialize method:

+(void)initialize {
	[MyClass validatesPresenceOf:@"city"];
	[MyClass validatesPresenceOf:@"state"];
}

You can declare your validations elsewhere if you like, but +(void)initialize is a good place because it's declarative and is only called once.

Once your validations are declared, you can check for object validity with the valid message.

NSMutableArray *errors = nil;
if ([myObject valid:&errors]) {
	// yay!  proceed as planned
} else {
	// handle the validation errors.  error objects contain the member name and an error message
}

The errors argument is optional, but useful if you would like details about which validations failed.

For a list of all available validations, look at NSObject+MMValidation.h

For detailed usage, look at the example code.

Mike Mayo - greenisus@gmail.com - http://overhrd.com - Twitter: @greenisus