Re: documentation on putp/getp

On Friday 04 March 2005 01:46 pm, Ralf Juengling wrote:
> 
> ? ^Aputp
> 
> ------------------------------------------------------------------------
> (putp <anything> <name> <value>)              [DE](sysenv.lsh)
> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
> 
> Every Lush object (atoms, cons, etc.) may be enriched by defining
> properties identified by a symbolic name. Function putp is used to
> define such properties. Its first argument is an arbitrary Lush object
> anything . Function putp sets the property named by symbol name to value
> value . Properties can be later retrieved using getp .
> 
> 
> Something like this should be added to the documentation:
> 
> NOTE: Do not apply putp to temporary objects! putp increases
> an object's reference counter, which will prevent a temporary
> object ever to be garbage collected.

Not true.

? (defclass x object)
= x
? (defmethod x -destructor() (print 'destroy x)))
= -destructor
? (new x)
= ::x:88467f8
? 2  ;; this erase the variable 'result' which always contains the last result 
= 2
destroy ::class:x
?
? (let ((y (new x))) (putp y 'info 2) y)
= ::x:884b588
? 2
= 2
destroy ::class:x
?

I agree that this is not obvious when you 
see how getp and putp are implemented.
This is because htables with == semantic
also handle their keys as weak pointers.
This is actually documented somewhere...

? ^Aassociations with hash


- L.





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