is there an existing negate function ?

is there an existing negate function ?

[Mike Mattie]

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is there an existing negate function ? something like this
that I have no found ?

(defun negate ( value )
  "negate VALUE

   Invert the boolean sense of VALUE

   0 -> 1
   1 -> 0
  "
  (if value
    nil
    t))

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Re: is there an existing negate function ?

[Juanma Barranquero]

> is there an existing negate function ? something like this
> that I have no found ?
>
> (defun negate ( value )
>  (if value
>    nil
>    t))

`null' (or its alias, `not').

    Juanma

RE: is there an existing negate function ?

[Drew Adams]

> is there an existing negate function ? something like this
> that I have no found ?
> 
> (defun negate ( value )
>   "negate VALUE - Invert the boolean sense of VALUE
>    0 -> 1
>    1 -> 0"
>   (if value nil t))

I'll bite. ;-)

Is `not' (aka `null') what you mean?
(not nil) -> t
(not 'non-nil) -> nil