Enable multi-field / field comparison validation

[pylons]

Enable multi-field / field comparison validation

[mcdonc]

If you use Deform, you get this for free:

http://deformdemo.repoze.org/checkedpassword/

http://deformdemo.repoze.org/interfield/

http://deformdemo.repoze.org/require_one_or_another/

You can write your own form system on top of Colander that does similar if deform doesn't work for you, but Colander is unlikely to make any concessions to doing it that it doesn't already.

[oveddan]

Can you explain what's the reason for this not to be part of colander?

I find Colander to be an excellent standalone library - particularly good for the use case when you just want a thin REST api to provide input validation.

Deform is overkill for that situation since all it adds is the ability to render forms and the confirm password widget. Also it's kind wonky how the validation happens within a widget.

This for me is the one missing feature from Colander.

[mcdonc]

Because I don't need "this" (whatever "this" is, it's hard to tell from your description exactly what you want).. and since I don't need "this", I'm not going to code "this". You are welcome to, however.

[oveddan]

"This" meant multi-field validation. It seems like you can actually do this via inter-field validation with a schema-wide validator:
http://deformdemo.repoze.org/interfield/

Does this work without deform?

[tseaver]

Yes, there is nothing deform-specific about the schema or validator defined in that example: you spell the inter-field constraints via the validator on the node which contains them.