Re: [Sbcl-help] sb-alien:enum question

[Thomas F. B. <tfb@OCF.Berkeley.EDU>]

Cyrus Harmon writes:
 > (setf (sb-alien:deref moose-var) :bear) to set the value to :bear.  
 > Other keywords don't work, which is great. Is there a way to actually  
 > get the value represented by the keyword :bear in the context of the  
 > enum? I know this sort of defeats the purpose of the enum, but it  
 > would still be nice to get.

Sure.  When you dereference a (* moose-enum), you get a valid
moose-enum value.  If you want an int, you should be dereferencing a
(* int).  How do you get from the one to the other?  By casting it,
naturally.

  (defun moose-to-int (moose)
    (deref (cast moose (* int))))

DEREF, CAST, and INT are all in the SB-ALIEN package of course, but if
you're writing code that uses Alien, you really want to be working in
a package the uses SB-ALIEN so you can see the content for the package
qualifications.

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