[pro] [Q] introspecting setf expanders

Didier Verna didier at lrde.epita.fr
Mon Oct 8 15:38:42 UTC 2012

Pascal Costanza wrote:

> Just guessing: If you see that the writer form is a funcall to a setf
> function, you can then check with fboundp if such a function actually
> exists. This is probably a bit shaky, but maybe good enough for
> practical purposes?

  Good idea. To be more precise:

- if the writer form is something else than (FUNCALL #'(SETF FOO) ...)
  then there is a defsetf going on (it even takes precedence over a
  potential setf function).

- if the writer form is (FUNCALL #'(SETF FOO) ...) and that function is
  bound, then there is a setf function going on but no defsetf.

- otherwise, there is no writer at all.

I think this might just work.

Resistance is futile. You will be jazzimilated.

Scientific site:   http://www.lrde.epita.fr/~didier
Music (Jazz) site: http://www.didierverna.com

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