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st: RE: RE: RE: RE: Referring to a varname, leading to errors


From   Joly.Patrick@ic.gc.ca
To   statalist@hsphsun2.harvard.edu
Subject   st: RE: RE: RE: RE: Referring to a varname, leading to errors
Date   Tue, 11 Feb 2003 16:12:47 -0500

Nick wrote
> But let's pose a question to Stata Corp and one to users.
>
> 1. Stata Corp
> =============
>
> Suppose a user like Glen doesn't want to be bitten
> ever by this. Imagine that such users can
>
> . set literalvarnames on
>
> meaning
>
> "Listen here, Stata: you are to behave, given my
> input, as if you never allowed abbreviated variable names."

... something akin to pragmatic modules in Perl, i.e. a way to instruct
Stata how we'd like it to behave.  Even Stata's version control facilities
can be viewed as such (right?), so perhaps it might not be that difficult to
implement.


>
> How easy would that be? Would there be side-effects?
> Well written programs that Glen uses, consciously
> or not, should all make use of temporary variables,
> but in practice there may be exceptions.
>
> In practice, perhaps, the issue is Command window input PLUS .do
> files.
>
> 2. Users
> ========
>
> Do you want what Glen wants? Not disallowing all
> variable name abbreviations, which I guess will
> never happen, but being able to set this for yourself
> to avoid what Glen describes.
>
> Nick
> n.j.cox@durham.ac.uk
>

To which Lee Sieswerda replied
> I, for one, never use varname abbreviations. Perhaps in some deep
> recess of my psyche I believe in Murphy's Law and don't want to run
> into Glen's problem inadvertantly.


Abbreviations can hurt you even if you don't ever use them, such as

i)  dropping a variable you never intended to drop; or

ii) inadvertently modifying the wrong variable

For e.g., at some point in time your data contains variables _foo_ and
_foobar_.  You no longer need _foo_ so you -drop- it.  Later, (wrongly)
believing _foo_ is still defined, you -replace foo = ...- but it modifies
-foobar- instead since Stata finds no ambiguity in the string literal _foo_.
You might never notice this blunder.  Dealing with large datasets at times,
with hundred of variables possessing names that differ by only a character
or two, this can have unfortunate consequences.  I almost never use
abbreviations myself either and typically, when I want to modify _foo_, it
is _foo_ I want to change and certainly *not* _foobar_.

Granted, if nothing can be done to let users specify Stata's behaviour via a
pragmatic command, some cost-benefit analysis must be made to weigh user
convenience vs. safety-features.  And if that's the case, then I can live
with it.  But if the sole explanation for this behaviour is rooted in
history (of Stata's development that is), then it becomes increasingly
difficult to buy into the cost-benefit justification.  To have the option of
turning off all abbreviations would be a monumental safety improvement IMHO.


Patrick Joly
joly.patrick@ic.gc.ca
pat.joly@utoronto.ca
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