Re: [Audacity-nyquist] *scratch* property values not protected from deletion?

[edgar <edg...@we...>]

Roger wrote:

 > Symbols are never garbage collected, so you do not need to set them
 > to non-nil values to keep them around.
 >
 > The main problem is that when you write:
 >
 > (setf *scratch* nil)
 > (putprop *scratch* ...)
 >
 > *scratch* is evaluated as an argument, so if the value is NIL, you
 > are passing NIL to putprol. NIL is not a symbol, so it cannot have
 > a property list.

Thanks, thats right, definetly my fault. As it turns out, by quoting
*scratch* I do NOT need to set *scratch* to any variable or function
value before using PUTPROP. After a fresh start of Audacity (to make
sure no values are bound to *scratch*), even with in-between GC runs
it works:

(putprop '*scratch* 'value 'property)
(gc)
(format t "~a~%" (get '*scratch* 'property))

prints:

VALUE

Okay, the GC test is a bit over-paranoid, but it's always better to
go for sure (says the repair-man edgar) ...

Thanks again,

- edgar





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