Apostasy seems a little strong, Gene... :-)
According to the help file, "Whenever possible, use EVALUATE( ) or a name
expression to replace macro substitution using the & Command. EVALUATE and
name expressions execute faster than macro substitution."
Macro expansion is incredibly useful, of course, and used to be the only
way to accomplish a lot of things of this ilk. Name expressions and
EVALUATE() came along and obviated the need to use macro expansion for
many of those things but not all of them. If you have some kind of loop
with a macro inside of it, the EVAL or name epxression can be
significantly faster over the lifetime of the loop.
I think the explanation is that it takes less time to do the VFP equivalent
of dereferencing a pointer to an object, because & can refer to anything,
including a very long executable expression, so there's a lot more parsing
that goes on with &.
But I dispute the "whenever possible" recommendation, because to use
EVALUATE() requires at least two lines of code: assign the results of
EVALUATE() to a variable, and then do something with the variable. In most
cases, it takes four lines, because if you're following good procedure, you
need a line to declare the scope of that variable and then a line to assign
it a default value before you can use it. So the only time this matters
would be in a situation where the & is executed more than once on the same
value.
In any case, we're most likely dealing with time intervals of a few
thousandths of a second, so in the scheme of things...
I understand Gene's remark about apostasy. One can almost guarantee that
any time somebody recommends using & for something, somebody will
immediately jump in and say, No no no! Don't do that! It's a rote response
not always--or even maybe, often--justified by the specific circumstances.
Ken Dibble
www.stic-cil.org
_______________________________________________
Post Messages to: [email protected]
Subscription Maintenance: http://mail.leafe.com/mailman/listinfo/profox
OT-free version of this list: http://mail.leafe.com/mailman/listinfo/profoxtech
Searchable Archive: http://leafe.com/archives/search/profox
This message:
http://leafe.com/archives/byMID/profox/[email protected]
** All postings, unless explicitly stated otherwise, are the opinions of the
author, and do not constitute legal or medical advice. This statement is added
to the messages for those lawyers who are too stupid to see the obvious.
