scala-syntax | Scalameta pretty printer for better Scalafix refactorings | 3D Printing library

I am new to Scala and I am trying to decode its constructs, I learned about pattern matching and the syntax is similar to Java switch statement

Scala has a very nice support of partial functions, mainly because in Scala when you define a partial function it also defines an isDefinedAt function for it. And also Scala has orElse and andThen functions to work with partial functions.

Haskell does support partial functions by simply non-exhaustively defining a function (though they are strongly discouraged in Haskell community). But to define isDefinedAt function in general you have to use some sort of exception handling, which I'm not being able to figure out. Once isDefinedAt function is defined then it can be used to define orElse and andThen function is already there as (.).

In short, I want to define a function,