best way to add validation functions

[eluser]skattabrain[/eluser]
hello,

i've been trying to get my validation callbacks into some sort of single file so i can reuse the fucntions within this project as well as others.

i've been adding these validation functions to a helper file, but things don't seem to work right. is there a better way than to add these fucntions in a helper?

should i extend the validation class instead?

i haven't extended ci in anyway yet ... trying to get the most out of a vanilla install for easy upgrading etc ...