[REBOL] Re: Bug! in assignment to date! values with stacked set-path values
From: rotenca:telvia:it at: 12-Nov-2002 14:45
Hi Ladislav, Andrew, Carl
> This is an artifact that is caused by immutability of dates. (you may
> remember the discussion on the subject) The
>
> x/month: 1
>
> expression is only a hack, no real mutation occurs. Exactly the same hack
> can be written to modify the bits of integer numbers as I have shown.
It seems to me that the mutation hack is not enough to explain this. The
problem is that all the value are pre-fetched before the first assign start,
else with or without mutation the result should be right. Instead, the
pre-fetch works only with mutable values. The bug is prefetch the value of
set-path.
Neither parens can correct the problem.
Look at this:
>> a: "aaa" probe a/2: (a: "bbb" #"c") a
aca
== "bbb"
As you can see the a/2 continue to refer to the old string "aaa" also when the
parens block has changed the 'a value with "bbb". I can be wrong but i do not
see any mutation hack here.
---
Ciao
Romano
