Thanks Alex,
The penny just dropped for me as I was writing this mail - yup, I remember
now :)
I think "finally" will do what I need :)
Regards,
Kashyap
On Sat, Dec 2, 2023 at 11:35 PM Alexander Burger
wrote:
> Hi Kashyap,
>
> > Is there a reference implementation of external allocation using
> > miniPicoLisp?
> >
> > Here's what I'd like to do - Create a new function called "alloc" that
> > allocates some memory.
> >
> > (let A (alloc 100)
> > (poke A 0 10)) # poke simply writes a byte(10) at offset 0
>
> I do not know if anybody has done this in miniPicoLisp, but the official
> PicoLisp has functions 'buf' and 'byte' which behave that way:
>
>(buf A 100 # Allocate on the stack
> (byte A 10)
> (byte (+ A 7) 11)
> ... )
>
> 'buf' allocates memory on the runtime stack, and cleans it up when done.
>
>
> You can also explicitly allocate system memory to get the same effect, but
> this
> has more overhead:
>
>(let A (%@ "malloc" 'P 100) # Allocate memory
> (byte A 10)
> ...
> (%@ "free" NIL A) ) # Clean up
>
>
> > The part I want to ensure is that the memory that's allocated by alloc
> gets
> > collected by the GC.
>
> This does not make sense. The garbage collector traverses the 'heap'
> structures,
> managing used and unused cells (as discussed in our last mail). Memory
> allocated
> by 'buf' or malloc() does not contain cells reachable from Lisp data
> structures,
> and is therfore not known by the garbage collector. And as it is not part
> of the
> linked list of 'heap's, it will not be free'd.
>
> ☺/ A!ex
>
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