[Rd] a debugging difficulty

[Prof Brian Ripley]

The error message is easy to expand, and R is a bit inconsistent as we do 
have

  error("length of dimnames[%d] not equal to array extent",i+1);

I've seen similar things debugging recently, and don't know the cause.

On Thu, 18 Dec 2003, Patrick Burns wrote:

> I had an error to debug that turned out to be essentially:
> 
>  > NULL * matrix(1:4, 2)
> Error: dim<- length of dims do not match the length of object
> 
> 
> The equivalent of the NULL was a variable that was meant
> to be a scalar.  It took me a while to track down the problem
> because I was focusing on looking for arrays that were different
> than my expectation.
> 
> I think it could save substantial debugging time if the error message
> stated the dims and the length of the object.
> 
> Also with
> 
> options(error=dump.frames)
> 
> set before the command above, we get:
> 
>  > debugger()
> Message:  Error: dim<- length of dims do not match the length of object
> Available environments had calls:
> 1:
> 0:
> 
> Enter an environment number, or 0 to exit  Selection: 1
> Selection: 0
>  >
> 
> That is, there is apparently an environment to select, but
> trying to select it doesn't do anything.
> 
> This is with R version 1.8.1 on Windows and SuSe 8.2 (both precompiled).
> 
> 
> Patrick Burns
> 
> Burns Statistics
> patrick at burns-stat.com
> +44 (0)20 8525 0696
> http://www.burns-stat.com
> (home of S Poetry and "A Guide for the Unwilling S User")
> 
> ______________________________________________
> R-devel at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
> 
> 

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595