Clyde Schechter
>
> Assuming it could be implemented by Stata Corp. in a
> reasonable way, I
> would definitely want, and use, a feature which permitted me to ban
> abbreviated variable names. I completely endorse Glen
> Waddell's concerns
> about the way abbreviated names can introduce
> difficult-to-track-down
> errors. In past postings to this list, I have also
> proposed that the use
> of uninitialized macro names as null strings be banished
> (or, at least
> optionally banished with a setting). The two practices are
> conceptually
> related, and probably should be combined as a single
> setting that does
> both. It is hard to imagine a programmer who would want
> one but not the other.
I don't think it helps -- at least as a matter
of practical Stata lobbying -- to lump these two
issues together at all. The first has been well aired
in this thread, and so far the picture is that several
people say they want it, but this is all no more than
wishlist item until Stata Corp says how difficult it is
-- and indeed whether they think it is a good idea,
when all implications and side-effects are spelled out.
The second is the rule that if Stata encounters
the statement
. local mymac "`mymac'<stuff>"
then `mymac' evaluates to empty if not previously
defined. To put it another way, it is not an error
to refer to a non-existent macro, or one that is empty.
(In Stata's ontology, the two states of non-being
appear well nigh indistinguishable to the user.)
A parallel construct for globals is also
possible.
One of the most common ways this arises
is within a loop as a way of building up possibly very
long strings.
Invoking this rule is entirely avoidable in terms of what you write
by explicit initialisation of macros to empty strings.
As said, that doesn't make much difference to Stata, but it does
protect you against one kind of bug.
You can dislike this language detail on any sort of
grounds whatsoever, but the likelihood of it
being abolishable -- or even settable -- is,
I would guess, zero.
Again, I believe that the issue is not just a matter of what
users type and how it is to be interpreted by
Stata. It is one of how Stata interprets syntax,
from wherever it comes, including Stata's own
programs. And I surmise that setting this off
could only be done with a major side-effect
that many, many programs would be broken. Your
Stata would be unusable.
Nick
[email protected]
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