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From: UNBCIC@BRFAPESP.BITNET
Newsgroups: comp.lang.forth
Subject: Problems with DOES>
Message-ID: <9105061640.AA23668@ucbvax.Berkeley.EDU>
Date: 6 May 91 14:47:00 GMT
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Reply-To: UNBCIC%BRFAPESP.BITNET@SCFVM.GSFC.NASA.GOV
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The PFA cannot be changed. For example, if we create a set of words
to implement STRUCTs (RECORDs), they should leave the address of the field,
an address inside PFA (maybe PFA). This address would be used for ! or @.
But in the mean time, an garbage collection could ocurr, changing the PFA
address, scrambling with the program. Alas, you couldn't use the PFA in
any case, if PFA could change.

This mean that HEAP systems, with garbage collection, couldn't be used? No.
But the PFA should then be implemented as a virtual address, not a physical
one.

                              (8-DCS)
Daniel C. Sobral
UNBCIC@BRFAPESP.BITNET