Currently, my method for server-side form validation goes like so:

1) Each form is created with a hidden field named "toValidate" which passes a
value determining which set of rules to check.
2) In Application.cfm, I include a file called something like "validation.cfm"
which contains a switch the checks the value of #form.toValidate#. If it finds
a match, it goes over a series of conditionals verifying input length, format,
etc. When it finds errors, it stores them in a struct.
3) Back on the form page, which has been posted to itself, there is a check
for the length of the errors struct. If gt 0, we show the form and error
messages, else we process and go about our business

My question is how I can take this process and abstract it to CFCs. I think I
understand well enough how to use a CFC as the forms ACTION, and then how to do
the validation checks in a method called something like validate() for
instance, but from there I'm not so sure... for instance, if there were errors,
how do I pass those back to the form page?

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Are there other methods worth looking into? I've done a bit of searching for
resources on form validation with CFCs, and I can't find much.