Re: [NTG-context] Float caption feature request

5 May 2006


      Johannes Graumann wrote:
...
Hello,
In LaTeX (don't remember whether this is generic or specific to one of the
packages I used to use), the 'caption' command for floats came along this
way:
\caption[optional short version]{Caption}
we use [] for references, and once users want one alternative, they may 
want another one as well, so best cook up a generic mechanism
...
If one uses the 'optional short version' bit, the Table of Figures/Tables
present the short version rather than the whole caption (which in my case
is long paragraphs and makes the TOF/TOT unpractical). I would very much
like to have that functionality in context.
Thanks for any hints on how to achieve this. Poking around in the source did
not lead this newbie to a starting point ...
something

\def\MyCaption{\firstoftwoarguments}

...\MyCaption{bla}{more bla} 

or better, wrapped in a feature: 

\unprotect

% let's reuse this one in selectors (from syst-ext) 

\def\dofilterfromstr#1#2% max n
  {\ifcase#1\or
     \ifcase#2\or
       \strippedcsname\firstofoneargument
     \else
       \strippedcsname\gobbleoneargument
     \fi
   \or
     \ifcase#2\or
       \strippedcsname\firstoftwoarguments
     \or
       \strippedcsname\secondoftwoarguments
     \else
       \strippedcsname\gobbletwoarguments
     \fi
   \or
     \ifcase#2\or
       \strippedcsname\firstofthreearguments
     \or
       \strippedcsname\secondofthreearguments
     \or
       \strippedcsname\thirdofthreearguments
     \else
       \strippedcsname\gobblethreearguments
     \fi
   \or
     \ifcase#2\or
       \strippedcsname\firstoffourarguments
     \or
       \strippedcsname\secondoffourarguments
     \or
       \strippedcsname\thirdoffourarguments
     \or
       \strippedcsname\fourthoffourarguments
     \else
       \strippedcsname\gobblefourarguments
     \fi
   \or
     \ifcase#2\or
       \strippedcsname\firstoffivearguments
     \or
       \strippedcsname\secondoffivearguments
     \or
       \strippedcsname\thirdoffivearguments
     \or
       \strippedcsname\fourthoffivearguments
     \or
       \strippedcsname\fifthoffivearguments
     \else
       \strippedcsname\gobblefivearguments
     \fi
   \fi}

\def\filterfromvalue#1#2#3% value max n
  {\@EA\@EAEAEA\csname                   % we use the fact that an
     \@EA\ifx\csname#1\endcsname\relax   % undefined cs has become \relax
       \strippedcsname\gobbleoneargument % which we then gobble here
     \else
       \dofilterfromstr{#2}{#3}%
     \fi
     \endcsname\csname#1\endcsname}

\def\filterfromnext#1#2% max n {..}{..}{..}{..}
  {\csname\dofilterfromstr{#1}{#2}\endcsname}

% new, selectors

\definesystemvariable{sx}

\def\defineselector{\dodoubleargument\dodefineselector}
\def\setupselector {\dodoubleargument\dosetupselector}

\def\dodefineselector[#1][#2]{\getparameters[\??sx#1][\c!max=2,\c!n=1,#2]}
\def\dosetupselector [#1][#2]{\getparameters[\??sx#1][#2]}

\unexpanded\def\select#1%
  {\filterfromnext
     {\executeifdefined{\??sx#1\c!max}1}
     {\executeifdefined{\??sx#1\c!n  }1}}

\defineselector[caption][max=2,n=1]

\start
    \setupselector[caption][n=1]
    \placelist[figure][criterium=all]
\stop

\starttext

\placefigure
  {\select{caption}{zapf}{\input zapf \relax}}
  {}

\stoptext

i'll add selectors to the core 

Hans 

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