Ciaran Mulloy <crmulloy@gmail.com> writes:
> Inserting the following as a field formula in location @2$3:   
> :='(mapconcat 'identity (delete-dups (list @2$1..@>$1 @2$2..@>$2)) " ") 
> and doing a C-c or a C-u-C-c C-c generates an 'Invalid regexp: "Regular 
> expression too big"' error.
> ....
> It seems that I can reliably reproduce a bug that I haven't been able to 
> find on forums and that most other people have difficulty replicating. 
> If I've done something to my installation of emacs I'd love to find out 
> what has caused the problem.
>
> Is there a way of determining what could be my issue?

Hello Ciaran,

  long story short: digging in org-table.el I noticed
that functions f1=`org-table-formula-handle-first/last-rc'
and f2=`org-table-formula-substitute-names' were used
sometimes like this: (f2 (f1 x)), and sometimes
like this: (f2 x). 

  I conjecture it should always be (f2 (f1 x)), so I applied
to my org-table.el, reloaded its definitions with `eval-buffer'
and... it worked! 

  File formula.diff attached here shows the exact changes
that I applied on my org-table.el. (if you try formula.diff
and it works for you, beware that you need to remove or recompile
the old org-table.elc file).