in that base. If @var{base} is @code{nil}, then base ten is used.
Floating point conversion always uses base ten; we have not implemented
other radices for floating point numbers, because that would be much
-more work and does not seem useful.
+more work and does not seem useful. If @var{string} looks like an
+integer but its value is too large to fit into a Lisp integer,
+@code{string-to-number} returns a floating point result.
The parsing skips spaces and tabs at the beginning of @var{string}, then
reads as much of @var{string} as it can interpret as a number. (On some