It is not just underscore; it is ' _ '. So your string would look like "blah blah" _ $d->func _ "somestuff". Not a big diff. My biggest gripe with it is that I know I am going to wind up typing "blah blah" - $d->func _ "somestuff" and wondering why I print 0somesutff. But it looks like I will be able to say "blah blah $($d->func) somestuff" which avoids the problem and looks nicer to me anyways.