@defmac cl-pushnew x place @t{&key :test :test-not :key}
This macro inserts @var{x} at the front of the list stored in
-@var{place}, but only if @var{x} was not @code{eql} to any
-existing element of the list. The optional keyword arguments
-are interpreted in the same way as for @code{cl-adjoin}.
-@xref{Lists as Sets}.
+@var{place}, but only if @var{x} isn't present in the list already.
+The optional keyword arguments are interpreted in the same way as for
+@code{cl-adjoin}. @xref{Lists as Sets}.
@end defmac
@defmac cl-shiftf place@dots{} newvalue
@section Lists as Sets
@noindent
-These functions perform operations on lists that represent sets
-of elements.
+These functions perform operations on lists that represent sets of
+elements. All these functions (unless otherwise specified) default to
+using @code{eql} as the test function, but that can be modified by the
+@code{:test} parameter.
@defun cl-member item list @t{&key :test :test-not :key}
This function searches @var{list} for an element matching @var{item}.