Page 171 introduces the usage of an operator used in Ecto queries used to interpolate values. As explained by this Stack Overflow answer, although the operator is the same character as the pin operator (a caret, a.k.a the ‘^’ character), the Ecto DSL uses it for a completely different purpose (ie. interpolating the names of values in the query, and yes, I probably phrased that wrong).

For some background, I am familiar with the concept of the pin operator, although I am honestly not sure about its actual use cases in the language (ie. I understand in a definitional sense, but I have yet to encounter a place where I would actually use it in my code). I am somewhat familar with Ecto queries in a broad sense, but I am definitely a beginner when it comes to using Ecto.

I feel that a brief paragraph of text would be warranted that would say, more or less, that “This operator is used in Ecto in such-and-such a way. Although this operator is identical to Elixir’s pin operator, it does not function the same way the pin operator does, and it is not a pin operator.” The behaviour of overwriting a language’s built-in functionaly is quite unusual and absolutely warrants a mention IMO.

Thanks