Re: Long-name/short-name complexity

[John Darrington]

On Mon, Apr 25, 2005 at 07:48:23PM -0700, Ben Pfaff wrote:
     [snip]

     I think that adopting the model I describe above makes sense.  I
     don't think there's any need to maintain any map, because we can
     resolve any conflicts at SAVE (EXPORT, etc.) time.  When we
     create a new variable without reference to a system file, we
     don't have to assign it a short name at all; again, that can be
     delayed until SAVE.
     
     Renaming is easy with this model.  If we want SPSS-compatible
     behavior for renames, renaming variables doesn't change the short
     name.  If we want "enhanced" behavior, renaming variables deletes
     the short name, because that will cause those variables to
     receive new and appropriate short names at SAVE time.  It'll be
     easy to support either behavior with our usual command-line
     switch.


I agree with your comments and your conclusion.

I suppose I was hoping to do away with one of the names in 
struct variable, because it would make for better encapsulation.  But
if we leave it there, it's certainly simpler and more efficient than
using a map.  (If only we were using C++, then the short name could be
a private member variable .... )

The fact that SPSS v12 (unlike PSPP 0.3.2) seems to always write its
system files with the order of its variables consistent with that of
its name table, suggests that SPSS uses the implementation you've
described.


J'

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