Re: Orphans/Widows in the Index

["Jan Tosovsky" <j.tosovsky@email.cz>]

On 2014-06-23 Jan Tosovsky wrote:
> On 2014-04-23 Jan Tosovsky wrote:
> >
> > in my auto-generated two column index (registry) there are
> > several cases of widows - it is the last item of the given
> > letter which overflows to next column/page:
> >
> >     --------------- (start page) -------
> >     Usti 29 (! alone !)
> >
> >     V
> >     Vamberk 18
> >     ...
> >     ...
> >
> >
> > There are also few cases of orphans, but this is not so strange:
> >     ...
> >     ...
> >     Josef 29
> >
> >     K
> >     Karel 69 (! alone !)
> >     ---------------- (end page) ---------
> >
> 
> I think both cases could be eliminated by establishing a new constraint
> to the 'key letter':
> (1) There must be 0 or at least 3 lines at the beginning of the
>     page/column before the Key letter.
> (2) There must be at least 2 lines after the Key letter.
> 
> Can this be somehow set in my source file?
> 

I've found the corresponding code in strc-reg.mkiv:

\setvalue{\??registerindicator a}#1%
  {\registerparameter\c!before
   % bugged, why does leftskip gets set:
\vskip\lineheight\goodbreak\vskip-\lineheight
   \begingroup
   \useregisterstyleandcolor\c!style\c!color   
   \dontleavehmode
   \strut
   \iflocation
     \dosetdirectpagereference{\currentregister:\v!section:#1}%
   \fi
   \registerparameter\c!command{#1}%
   \endgroup
   \blank[\v!samepage]%
   \registerparameter\c!after
   \par
   \nobreak}

That (2) case can be fixed by a small change:
\testcolumn[3]\registerparameter\c!command{#1}%

But when tested on this MWE, you can see a drawback - the first letter (p)
starts always on the second line (not on the first one):

\setupregister[balance=yes]
\starttext
\index{primary+secondary+tertiary}
\index[primary long]{\dorecurse{5}{primary long }}
\index[primary longer]{\dorecurse{5}{primary longer }}
\input{tufte}
\completeindex
\stoptext

Can this issue somehow be eliminated? Tested on the last beta (with my
patch).

That (1) case is still open. I have no idea how to accomplish something like
this using (Con)TeX(t) syntax :-(

Thanks, Jan


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