scalar

See the current Perl documentation for scalar.

Here is our local, out-dated (pre-5.6) version:

scalar - force a scalar context

scalar EXPR

Forces EXPR to be interpreted in scalar context and returns the value of EXPR.

    @counts = ( scalar @a, scalar @b, scalar @c );

There is no equivalent operator to force an expression to be interpolated in list context because it's in practice never needed. If you really wanted to do so, however, you could use the construction @{[ (some expression) ]}, but usually a simple (some expression) suffices.