LET-IF

["Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>]

    What if the variable is unbound?

Well, in that case it usually does no harm to rebind the thing
unconditionally.  The code would then look like

(let ((foo (if (boundp foo) foo foo-default)))
  ...)

I grant that a user might want to use a macro to abbreviate the above
idiom if it is used a lot, but it is probably not something that is used
enough to belong in the langauge proper.  Are there other common uses of
LET-IF that would not be captured adequately by something like the
above?

-- Scott