Function calls and strings

Hello.

PHP possesses what the manual calls "complex syntax" for allowing one to 
include non-trivial expressions in strings, e.g.:

   $s = "The result is {$results[$foo]}.";

I seek to find out whether PHP also has a syntax to allow function calls 
within a string, so that explicit concatenation is not needed. E.g.:

something like:

   $s = "The result is {getResult($foo)}.";

as opposed to

   $s = "The result is " . getResult($foo) . ".";

If that is not possible, I would appreciate if someone could suggest the 
rationale.

Thank you,

-- 
Ney André de Mello Zunino