Returns the documentation string of proc if it exists, or
#f if not.
If the body of a
lambda (or the definition of a procedure) has
more than one expression, and the first expression (preceeding any
internal definitions) is a string, then that string is the
documentation string of that procedure.
(procedure-documentation (lambda (x) "Identity" x)) ⇒ "Identity" (define (square x) "Return the square of X." (* x x)) ⇒ #<unspecified> (procedure-documentation square) ⇒ "Return the square of X."
Appends string1 … to the strings given as arguments to
Returns the (appended) strings given as arguments to previous calls
comment and empties the current string collection.