I want my clients to be able to write something like `something <%= temp(@conn) %> something` where the `temp/1` function out of a specified module would be called and the output inserted whenever I display that. The set of functions would be very limited and predefined in this case because I don't want them to kill something.

How would I go about this?

To make it clear: I have sensors which have names. The client can edit these names to display whatever they want in the format they want when they go to a dashboard.