First of all choroba's code can be easily sped up by replacing the ->new with a direct bless

Syntax is rarely about speed otherwise you would do it right away in assembler.

In this particular example speed ups could be implemented if multiple operations happen

Something like

speed { L ($x, $y) * 3 + [5,6] + L (@z) };

wouldn't even need XS to be efficient, the objects inside the block would return optimized Perl code which is eval'ed only once and then reexecuted inside an inner loop.

With Keyword::Simple° even the overhead of calling speed could be avoided by inlining the code at compile-time.

°) which has an XS dependency but only needs Perl to be used.