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What is going on with this interpolated module attribute?

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elt547

elt547

What is going on with this interpolated module attribute?

I was just watching a conference video on pubsub and there was a module attribute defined with interpolation and passed as the topic id. Is there something magical going on here? How is the chat_id interpolated into the string from the module attribute at runtime? I thought they were meant to serve more as compile-time constants.

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al2o3cr

al2o3cr

Even if there was a version of Elixir where that #{ } didn’t evaluate until later it still wouldn’t make any sense - there’s no chat_id binding in scope inside mount!

This feels like a “well the ACTUAL implementation won’t fit on a slide” situation.

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