The project is providing the THE* macro that takes name of some numeric type and a form and wraps that form recursively into (THE <TYPE> ...). So

(THE* FLOAT 1) --> (THE FLOAT 1.0)
(THE* SIGNLE-FLOAT (SIN (/ 1 4))  -->  (THE SINGLE-FLOAT (SIN (THE SINGLE-FLOAT (/ (THE SINGLE-FLOAT 1.0) (THE SINGLE-FLOAT 4.0)))))