Common Lisp does allow one to declare types in order to have the compiler optimize the code. SBCL[0] in particular is known to be pretty good at that. Macsyma a

Common Lisp does allow one to declare types in order to have the compiler optimize the code. SBCL[0] in particular is known to be pretty good at that. Macsyma also lives on in Common Lisp as Maxima[1]. [0]: http://sbcl.org/ http://sbcl.org/ [1]: http://maxima.sourceforge.net/ http://maxima.sourceforge.net/