Using -spec for callbacks when defining behaviours

Steve Davis <>
Fri Mar 19 00:46:09 CET 2010

Hi Mikael,

On Mar 18, 6:33 am, Mikael Karlsson <> wrote:
> I do not think any of the proposed things will be mandatory, but
> optional,
> you can choose to use them at your own will.

For sure, and it's an interesting and useful discussion to have.

> > fwiw, a year ago I would probably have been an active advocate of more
> > language support for type constraints, but the longer I spend building
> I confess I have very ambigous feelings about this, and partly agree,
> ..but
> if opaque types (or abstract data types/patterns) become more frequent
> in
> Erlang I guess there will be more need for type specifications.

I'd temper this with the known effective approaches:
1) "let it crash"
2) apply checks only at the application/system boundary which I'll add...

3) beware any form of cruft.


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