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> It is allowed to redefine the predeclared identifiers, but
> not the reserved words.
>
Yes, that is true. The history of NIL is interesting. It was originally
a reserved word in Pascal. It became a standard identifier in Modula-2,
but then reverted back to being a reserved word in Oberon, and hence,
Component Pascal.
NIL is in a different league to other constants such as FALSE and TRUE
in that it circumvents the usual type-checking rules - it is
type-compatible with ANY pointer. If you redefined it in a program then
that would severely impact your ability to explicitly initialise
pointers in that program.
Chris Burrows
CFB Software
http://www.cfbsoftware.com/gpcp
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Received on Mon Oct 18 2004 - 02:49:50 UTC