[lmm]

"_" in Scala is not a magic variable like in Perl. It's a very mechanical syntax transformation, it just expands to "x => x" (or equivalent, and without colliding with any "x" that's already defined).

In practice maybe the use is similar. But having a comprehensible theoretical model makes all the difference in terms of making sure you can actually read the code and understand what will happen.

[Mithaldu]

There is nothing particularly magical about $_. It is merely a global variable that is optionally used implicitly in various builtins, as well as scope-localized by loop control constructs.

[lmm]

Are you sure you're not just used to it? The description you've just given sounds very magic to me.

[Mithaldu]

That depends on how you define "magic". I typically do so as "cannot be implemented in the language itself", which does not apply to $_, as it can be reimplemented in Perl itself. If i was bored enough i could create a module that sets up a $this variable that acts exactly the same, in pure perl.