Which Lisp? What applications do you think it is slow at? Hint: It can be faster than C due to compiler macros, and infact, its regular expression engine is muc

Which Lisp? What applications do you think it is slow at? Hint: It can be faster than C due to compiler macros, and infact, its regular expression engine is much faster than Perl's, which is written in C, just to give a concrete example.