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Re: understanding code

  • To: mathgroup at smc.vnet.net
  • Subject: [mg114221] Re: understanding code
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Sat, 27 Nov 2010 03:38:43 -0500 (EST)

On 11/26/10 at 5:49 PM, lshifr at gmail.com (Leonid Shifrin) wrote:

>PreIncrement must have been implemented on the higher level, using
>Set

Your example makes sense.

>In any case, there seem to be no additional restrictions imposed by
>PreIncrement on an expression being incremented, as compared to
>those of Set (that it must be an L - value). Particularly, indexed
>variables like i[1] are ok.

I would say that using i[1] to be an indexed variable is
something that needs to be done with care. When a value is
assigned such as i[1]=0, i now has a down value. But for an
ordinary variable x doing x = 1 does not create a down value.
This difference means using i[1] to be and indexed variable will
result in different behavior than using an ordinary variable in
some cases.



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