Re: [vile] toggle boolean settings

[Thomas Dickey]

On Wed, Feb 29, 2012 at 05:15:36PM -0500, Thomas Dickey wrote:
> On Wed, Feb 29, 2012 at 01:51:46PM -0500, address@hidden wrote:
> > Is there a way to simply negate boolean settings? If not it would be
> > nice to have a feature like this:
> > 
> > setl !list
> > or
> > setl notlist
> > 
> > If listing is enabled it would be disabled, else enabled.
> 
> I do this with a macro ToggleList, for just the special case of the list
> mode.  That, and ToggleTabs have been useful enough as is, that I hadn't
> considered making it more general.
> 
> One way to make it more general would be to make something like this
> work (that is, gluing "$" onto the mode name and feeding that into
> the interpretation):
> 
>       store-procedure invert mode="Mode to invert"
>       write-message &cat "Hello:" $*
>       ~if &cat "$" $1
>       write-message &cat "HI:" $*
>       ~else
>       ~if $list
>       write-message &cat "OOPS:" $*
>       ~else
>       write-message &cat "BYE:" $*
>       ~endif
>       ~endif
>       ~endm
> 
> A quick check showed me it doesn't work, but that's the sort of thing
> that macros would be good for.  (I also considered "eval" for the "~if"
> line, but the "~" and "&" stuff _is_ processed before that, so it
> wouldn't work).

Revisiting this, the solution is to use the "&ind" function, e.g.,

        ~if &ind $1

-- 
Thomas E. Dickey <address@hidden>
http://invisible-island.net
ftp://invisible-island.net

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