= in scala is the actual assignment operator — it does a handful of specific things that for the most part you don’t have control over, such as
- Giving a
valorvara value when it’s created - Changing the value of a
var - Changing the value of a field on a class
- Making a type alias
- Probably others
:= is not a built-in operator — anyone can overload it and define it to mean whatever they like. The reason people like to use := is because it looks very assignmenty and is used as an assignment operator in other languages.
So, if you’re trying to find out what := means in the particular library you’re using… my advice is look through the Scaladocs (if they exist) for a method named :=.