Here is an example that defines a presentation translator to accept an integer object from a float presentation. Users have the options of typing in a float or integer to the input prompt or clicking on any float or integer presentation.
(define-presentation-translator integer-to-float
(integer float my-command-table
:documentation "Integer as float"
:gesture :select
:tester ((object) (integerp object))
:tester-definitive t)
(object)
(float object))
(clim:present most-positive-fixnum)
(clim:accept 'float)