%D \module
%D   [       file=scrn-fld,
%D        version=1997.05.18,
%D          title=\CONTEXT\ Screen Macros,
%D       subtitle=Fields,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Screen Macros / Fields}

\unprotect

%D First we hook fields into the (viewer based) layering mechanism
%D (implemented as properties).

\appendtoks
  \doif\@@iafieldlayer\v!auto{\def\@@iafieldlayer{\currentviewerlayer}}%
\to \everysetupinteraction

\setupinteraction
  [\c!fieldlayer=\v!auto] % auto by default

%D \starttyping
%D \definefield [name] [type] [group] [values] [default]
%D
%D \definefield [WWWW] [text]  [textsetup]            [default text]
%D \definefield [XXXX] [push]  [pushsetup]  [yes,no]  [yes]
%D \definefield [XXXX] [check] [checksetup] [yes,no]  [yes]
%D \definefield [YYYY] [combo] [combosetup] [a,b,c,d] [b]
%D \definefield [ZZZZ] [radio] [radiosetup] [W,X,Y,Z] [Y]
%D
%D \definesubfield [W]   [subsetup] [p,q]
%D \definesubfield [X,Y] [subsetup] [p,r]
%D \definesubfield [Z]   [subsetup] [y,z]
%D
%D evt \definemainfield ... wanneer geplaatst voor subs gegeven
%D
%D \clonefield [XXXX] [XX,YY] [mysetup]      [on,off]
%D \clonefield [Z]    [AA,BB] [somesetup]    [true,false]
%D \clonefield [Z]    [CC,DD] [anothersetup]
%D
%D \copyfield [XXXX] [PP,QQ,RR]
%D
%D \field[XXXX]
%D \fitfield[XXXX]
%D \stoptyping

%D Internal command, linked to \type{\definesymbol}.

\def\dogetfieldsymbol#1%
  {\getobject{SYM}{#1}}

\def\dopresetfieldsymbol#1%
  {\doifobjectfoundelse{SYM}{#1}
     {}
     {\settightobject{SYM}{#1}\hbox{\symbol[#1]}%
      \flushatshipout
        {\setbox0\hbox{\hskip-\maxdimen\getobject{SYM}{#1}}%
         \smashbox0\box0}}}

\def\presetfieldsymbols[#1]% slow
  {\def\dopresetfieldsymbols##1{\processcommalist[##1]\dopresetfieldsymbol}%
   \@EA\processcommalist\@EA[#1]\dopresetfieldsymbols}

\unexpanded\def\definedefaultsymbols
  {\definesymbol[defaultyes][\mathematics{\times}]%
   \definesymbol[defaultno ][\mathematics{\cdot }]}

\def\resetfieldsymbol[#1]% for experimental usage only
  {\resetobject{SYM}{#1}}

%D The interface to the specials. DEFAULT NOG ANDERS

\def\typesetfield
  {\bgroup
   \dosetfontattribute\??fd\c!style
   \ctxlua{backends.codeinjections.typesetfield("\currentfieldname", {
        title           = "\currentfieldname",
        width           = \number\dimexpr\@@fdwidth\relax,
        height          = \number\dimexpr\@@fdheight\relax,
        align           = "\@@fdalign",
        length          = tonumber("\@@fdn") or 0,
        style           = "\@@fdstyle",
        fontstyle       = "\fontstyle",
        fontalternative = "\fontalternative",
        fontsize        = "\currentfontbodysize",
        color           = "\@@fdcolor",
        backgroundcolor = "\@@fdfieldbackgroundcolor",
        framecolor      = "\@@fdfieldframecolor",
        layer           = "\@@fdfieldlayer",
        options         = "\@@fdoption",
        align           = "\@@fdalign",
        clickin         = "\@@fdclickin",
        clickout        = "\@@fdclickout",
        regionin        = "\@@fdregionin",
        regionout       = "\@@fdregionout",
        afterkey        = "\@@fdafterkey",
        format          = "\@@fdformat",
        validate        = "\@@fdvalidate",
        calculate       = "\@@fdcalculate",
        focusin         = "\@@fdfocusin",
        focusout        = "\@@fdfocusout",
   }) }%
   \egroup}

\unexpanded\def\definefieldset {\dodoubleargument\dodefinefieldset}
\unexpanded\def\definefield    {\doquintupleempty\dodefinefield}
\unexpanded\def\definemainfield{\doquintupleempty\dodefinefield} % redundant
\unexpanded\def\definesubfield {\dotripleempty   \dodefinesubfield}
\unexpanded\def\clonefield     {\doquadrupleempty\doclonefield}
\unexpanded\def\copyfield      {\dodoubleempty   \docopyfield}
\unexpanded\def\field          {\dodoubleempty   \donormalfield}
\unexpanded\def\fitfield       {\dodoubleempty   \dofitfield}
\unexpanded\def\setupfield     {\doquintupleempty\dosetupfield}
\unexpanded\def\setupfields    {\doquadrupleempty\dosetupfields}

% misc

% \appendtoks\ctxlua{backends.codeinjections.finishfields()}\to\everylastshipout

% testing

\def\doiffieldelse     #1{\ctxlua{backends.codeinjections.doiffieldelse("#1")}}
\def\doiffieldgroupelse#1{\ctxlua{backends.codeinjections.doiffieldgroupelse("#1")}}

% definition

\def\dodefinefield[#1][#2][#3][#4][#5]% [name] [kind] [group] [values] [default] | [name] [kind] [group] [default]
  {\ctxlua{backends.codeinjections.definefield{ variant="normal", name="#1", kind="#2", group="#3", values=\!!bs#4\!!es, default=\!!bs#5\!!es }}}

\def\dodefinesubfield[#1][#2][#3]% [name] [group] [values]
  {\ctxlua{backends.codeinjections.definefield{ variant="normal", name="#1", kind="sub", group="#2", values=\!!bs#3\!!es }}}

\def\doclonefield[#1][#2][#3][#4]% [parent] [children] [group] [values]
  {\ctxlua{backends.codeinjections.clonefield{ variant="clone", parent="#1", children="#2", group="#3", values=\!!bs#4\!!es }}}

\def\docopyfield[#1][#2]% [parent] [children]
  {\ctxlua{backends.codeinjections.clonefield{ variant="copy", parent="#1", children="#2" }}}

\def\dodefinefieldset[#1][#2]%
  {\ctxlua{backends.codeinjections.definefieldset("#1","#2")}}

% usage
%
% \iftrialtypesetting
%
% just a default setup

\def\loadfieldscripts{\useJSscripts[fld]\globallet\loadfieldscripts\relax}

\def\donormalfield{\doprocessfield\dohandlefield}
\def\dofitfield   {\doprocessfield\dohandlefitfield}

\def\dosetupfieldindeed#1#2[#3]% [#4][#5][#6][#7]%
  {#1[#2]} % [#4][#5][#6][#7]}

\def\doprocessfield#1[#2][#3]% \method [name] [label]
  {\dontleavehmode
   \begingroup
   \loadfieldscripts
   \edef\currentfieldname {#2}%
   \edef\currentfieldlabel{#3}%
   \edef\currentfieldgroup{\ctxlua{backends.codeinjections.getfieldgroup("#2")}}%
   \ifx\currentfieldlabel\empty
     \let\currentfieldlabel\currentfieldname
   \fi
   \ifx\currentfieldgroup\empty
     #1[#2][\v!label,\v!frame,\v!horizontal][][][]%
   \else
     \def\dosetupfield{\dosetupfieldindeed{#1}{#2}}%
     \getvalue{\??fd::\currentfieldgroup}%
   \fi
   \endgroup}

% setups

\def\dosetupfield[#1][#2][#3][#4][#5]%
  {\iffifthargument
     \def\docommand##1{\dodosetupfield[##1][#2][#3][#4][#5]}%
     \processcommalist[#1]\docommand
   \else\ifthirdargument
     \def\docommand##1{\dodosetupfield[##1][#2][][][#3]}%
     \processcommalist[#1]\docommand
   \else\ifsecondargument
     \doifelse{#2}\v!reset
       {\def\docommand##1{\donosetupfield[#1][][][][]}}
       {\def\docommand##1{\dodosetupfield[##1][][][][#2]}}%
     \processcommalist[#1]\docommand
   \else\iffirstargument
     \def\docommand##1{\dodosetupfield[##1][][][][]}%
     \processcommalist[#1]\docommand
   \else
     \writestatus\m!fields{provide either 1, 2, 3 or 5 arguments}%
   \fi\fi\fi\fi}

\def\normaldodosetupfield[#1][#2][#3][#4][#5]%
  {\ifcsname\??fd::#1\endcsname
     \pushmacro\dosetupfield
     \def\dosetupfield[##1][##2][##3][##4][##5]{\setvalue{\??fd::#1}{\dosetupfield[#1][##2,#2][##3,#3][##4,#4][##5,#5]}}%
     \getvalue{\??fd::#1}%
     \popmacro\dosetupfield
   \else
     \setvalue{\??fd::#1}{\dosetupfield[#1][#2][#3][#4][#5]}%
   \fi}

\let\dodosetupfield\normaldodosetupfield

\def\donosetupfield[#1][#2][#3][#4][#5]%
  {\setvalue{\??fd::#1}{\dosetupfield[#1][#2][#3][#4][#5]}}

\def\dosetupfields[#1][#2][#3][#4]%
  {\ifsecondargument
     \def\dodosetupfield[##1][##2][##3][##4][##5]%
       {\ifcsname\??fd::##1\endcsname
          \def\dosetupfield[####1][####2][####3][####4][####5]%
            {\setvalue{\??fd::##1}{\dosetupfield[##1][#1,####2,##2][#2,####3,##3][#3,####4,##4][#4,####5,##5]}}%
          \getvalue{\??fd::##1}%
        \else
          \setvalue{\??fd::##1}{\dosetupfield[##1][#1,##2][#2,##3][#3,##4][#4,##5]}%
        \fi}%
   \else\iffirstargument
     \doifelse{#1}\v!reset
       {\resetfields}
       {\setupfields[][][][#1]}% checken
   \else
     \writestatus\m!fields{provide either 1 or 4 arguments}%
   \fi\fi}

\def\resetfields
  {\let\dodosetupfield\normaldodosetupfield}

% \setupfields[\v!reset]

% opties: veld, label, kader, vertikaal/horizontaal

\newif\ifShowFieldLabel
\newif\ifShowFieldFrame
\newif\ifVerticalField
\newif\ifHorizontalField

% way to slow/complicated, we need some simple alternative
% as well

\def\dohandlefield[#1][#2][#3][#4][#5]%
  {\presetlocalframed[\??fd]%
   \processallactionsinset
     [#2]
     [      \v!reset=>\ShowFieldLabelfalse\ShowFieldFramefalse\HorizontalFieldfalse\VerticalFieldfalse,
            \v!label=>\ShowFieldLabeltrue,
            \v!frame=>\ShowFieldFrametrue,
       \v!horizontal=>\HorizontalFieldtrue,
         \v!vertical=>\VerticalFieldtrue]%
   \ifVerticalField
     \getparameters[\??fd][\c!distance=\zeropoint,\c!inbetween=\vskip\@@localoffset,\c!align=\v!right,\c!width=20em]%
   \else\ifHorizontalField
     \getparameters[\??fd][\c!distance=\@@localoffset,\c!inbetween=,\c!align=\c!left,\c!height=10ex]%
   \else
     \getparameters[\??fd][\c!distance=\zeropoint,\c!inbetween=,\c!align=\c!left]%
   \fi\fi
   \getparameters[\??fd][\c!n=,\c!before=,\c!after=\vss,\c!style=,\c!color=,#3]%
   \ifShowFieldFrame
     \localframed[\??fd][\c!strut=\v!no,\c!align=]\bgroup
   \else
     \vbox\bgroup
   \fi
     \dontcomplain
     \ifShowFieldLabel
       \setbox0\hbox
         {\reshapeframeboxtrue % else wrong dimensions
          \framed
            [\c!style=,\c!color=,\c!align=\c!right,#4]
            {\currentfieldlabel}}%
     \fi
     \setbox2\hbox
       {\reshapeframeboxtrue % else wrong dimensions
        \ifVerticalField
          \setupframed[\c!height=6ex,\c!width=\hsize]%
        \else\ifHorizontalField
          \setupframed[\c!height=\vsize,\c!width=20em]%
        \else
          \setupframed[\c!height=2cm,\c!width=2cm]%
        \fi\fi
        \framed
          [\c!align=\v!right,\c!strut=\v!no,#5]
          {\getparameters
             [\??fd]
             [\c!color=,\c!style=,\c!align=\v!right,\c!option=,
              \c!clickin=,\c!clickout=,\c!regionin=,\c!regionout=,
              \c!afterkey=,\c!format=,\c!validate=,\c!calculate=,
              \c!focusin=,\c!focusout=,
              \c!fieldoffset=-\framedoffset,\c!fieldbackgroundcolor=,
              \c!fieldframecolor=,\c!fieldlayer=\@@iafieldlayer,#5]%
            \scratchdimen\framedwidth \edef\@@fdwidth {\the\scratchdimen}%
            \scratchdimen\framedheight\edef\@@fdheight{\the\scratchdimen}%
            \vfill
            \hbox{\lower\@@fdfieldoffset\hbox{\typesetfield}}
            \vss}}%
     \ifShowFieldLabel
       \ifVerticalField
         \vbox
           {\copy0
            \@@fdinbetween
            \copy2}%
       \else
         \hbox
           {\vbox \ifdim\ht2>\ht0 to \ht2 \fi
              {\@@fdbefore
               \copy0
               \@@fdafter}%
            \hskip\@@fddistance
            \vbox \ifdim\ht0>\ht2 to \ht0 \fi
              {\@@fdbefore
               \box2
               \@@fdafter}}%
       \fi
     \else
       \box2
     \fi
   \egroup}

\chardef\fitfieldmode\plusone % 3 = best

\def\dohandlefitfield[#1][#2][#3][#4][#5]% alleen check
  {\presetlocalframed[\??fd]%
   \localframed
     [\??fd]
     [\c!n=1024, % beware: weblink plug in truncates
      \c!strut=\v!no,\c!color=,\c!style=,\c!option=,
      \c!clickin=,\c!clickout=,\c!regionin=,\c!regionout=,
      \c!focusin=,\c!focusout=,
      \c!afterkey=,\c!format=,\c!validate=,\c!calculate=,
      \c!fieldoffset=\zeropoint,\c!fieldbackgroundcolor=,
      \c!fieldframecolor=,\c!fieldlayer=\@@iafieldlayer,#5,\c!align=]
     {\edef\defaultfield{\ctxlua{backends.codeinjections.getdefaultfieldvalue("#1")}}%
    % \dopresetsymbol\defaultfield
    \setbox\scratchbox\hbox{\symbol[\defaultfield]}%
      \edef\@@fdwidth {\the\wd\scratchbox}%
      \ifcase\fitfieldmode
        \edef\@@fdheight{\the\ht\scratchbox}%
        \typesetfield
      \or % 1 = ignore depth (original, assumed no depth, actually a bug)
        \edef\@@fdheight{\the\ht\scratchbox}%
        \vbox to \ht\scratchbox{\vfill\hbox to \wd\scratchbox{\typesetfield\hfill}\vss}%
      \or % 2 = add depth to height, but no depth in result
        \edef\@@fdheight{\the\htdp\scratchbox}%
        \vbox to \ht\scratchbox{\vfill\hbox to \wd\scratchbox{\typesetfield\hfill}\vss}%
      \or % 3 = add depth to height, and apply depth to result
        \edef\@@fdheight{\the\htdp\scratchbox}%
        \hbox to \wd\scratchbox{\lower\dp\scratchbox\hbox{\typesetfield}\hfill}%
      \fi}}

%D Common stuff

\newcount\nofsystemfields

\def\nextsystemfield
  {\global\advance\nofsystemfields\plusone
   \def\currentsystemfield{sys::\number\nofsystemfields}}

%D An example:

\def\fillinfield
  {\dosingleempty\dofillinfield}

\def\dofillinfield[#1]#2%
  {\dontleavehmode
   \hbox
     {\forgetall
      \setupfields[\v!reset]%
      \nextsystemfield
      \useJSscripts[ans]%
      \doifelsenothing{#1}
        {\def\therightanswer{#2}}
        {\def\therightanswer{#1}}%
      \setbox0\hbox{#2}%
      \setbox2\hbox{\therightanswer}%
      \dimen0=\ifdim\wd0>\wd2 \wd0 \else \wd2 \fi
      \advance\dimen0 .2em
      \definefield
        [\currentsystemfield][line][systemfield]%
      \setupfield
        [systemfield]
        [\c!n=1024, % beware: weblink plugin truncates
         \c!location=\v!low,\c!strut=\v!yes,\c!fieldoffset=\zeropoint,
         \c!height=1.2\openlineheight,\c!width=\dimen0,\c!offset=\v!overlay,
         \c!style=,\c!align=\v!middle,\c!frame=\v!off,
         \c!color=red,\c!fieldbackgroundcolor=\s!white,\c!fieldframecolor=blue,
         \c!validate=JS(Check_Answer{\currentsystemfield,\therightanswer})]%
      \switchtobodyfont
        [\c!small]%
      \hbox to \wd0
        {\copy0\hskip-\wd0\hss\field[\currentsystemfield]\hss}}}

%D and another one:

\def\tooltip
  {\dosingleempty\dotooltip}

\def\dotooltip[#1]#2#3%
  {\dontleavehmode
   \begingroup
   \setupfields[\v!reset]%
   \useJSscripts[fld]%
   \setbox0\hbox
     {\dontcomplain
      \nextsystemfield
      \setbox0\hbox{#2}%
      \definesymbol
        [\currentsystemfield:txt]
        [{\inframed[\c!frame=\v!off,\c!background=\v!screen]{#3}}]%
      \setbox2\hbox{\symbol[\currentsystemfield:txt]}%
      \definefield
        [\currentsystemfield:txt][check]
        [dummy][\currentsystemfield:txt][\currentsystemfield:txt]%
      \setupfield
        [dummy]
        [\c!frame=\v!off,
         \c!regionout=JS(Hide_Field{\currentsystemfield:txt}),
         \c!option=\v!hidden]%
      \hbox to \zeropoint
         {\dimen0\wd2\advance\dimen0 -\wd0
          \doifelse{#1}\v!left
            {\hskip-\dimen0}
            {\doif{#1}\v!middle
               {\hskip-.5\dimen0}}%
          \lower\openlineheight\hbox to \zeropoint
            {\fitfield[\currentsystemfield:txt]}}%
      \dimen0=\ifdim\wd0=\zeropoint 3em\else\wd0\fi
      \definesymbol
        [\currentsystemfield:but]
        [{\framed[\c!height=2ex,\c!width=\dimen0,\c!frame=\v!off]{}}]%
      \definefield
        [\currentsystemfield:but][push]
        [dummy][\currentsystemfield:but][\currentsystemfield:but]%
      \setupfield
        [dummy]
        [\c!frame=\v!off,
         \c!option=,
         \c!regionin=JS(Vide_Field{\currentsystemfield:txt}),
         \c!regionout=JS(Hide_Field{\currentsystemfield:txt}),
         \c!fieldlayer=\@@iafieldlayer]%
       \lower2ex\hbox to \zeropoint
         {\fitfield[\currentsystemfield:but]}%
      #2}%
  \ht0\strutht\dp0\strutdp\box0
  \endgroup}

%D And one more:

\unexpanded\def\definefieldstack
  {\dotripleargument\dodefinefieldstack}

\def\dodefinefieldstack[#1][#2][#3]% name, symbols, settings
  {\ifcsname fieldstack:#1\endcsname \else
     \setgvalue{fieldstack:#1}{\dodofieldstack[#1][#2][#3]}%
   \fi}

\def\fieldstack
  {\dotripleempty\dofieldstack}

\def\dofieldstack[#1][#2][#3]%
  {\ifsecondargument
     \dodefinefieldstack[#1][#2][#3]\fieldstack[#1]%
   \else
     \getvalue {fieldstack:#1}%
     \setgvalue{fieldstack:#1}{[#1]}%
   \fi}

\def\dodofieldstack[#1][#2][#3]% start=n, 0 == leeg
  {\dontleavehmode
   \begingroup
   \getparameters[\??fd][\c!start=1,#3]%
   \setupfields[\v!reset]%
 % \definesymbol[\v!empty][]%
   \useJSscripts[fld][FieldStack]%
   \newcounter\stackedfieldnumber
   \def\dododofieldstack##1%
     {\increment\stackedfieldnumber
      \ifnum\stackedfieldnumber=\@@fdstart\relax
        \definefield[#1:\stackedfieldnumber][check][#1][##1,\empty][##1]% \v!empty fails
      \else
        \definefield[#1:\stackedfieldnumber][check][#1][##1,\empty][\empty]% \v!empty fails
      \fi}%
   \processcommalist[#2]\dododofieldstack
   \setupfield[#1][\v!reset]% added
   \setupfield[#1][\c!option=\v!readonly,#3]% #3 swapped
   \newcounter\stackedfieldnumber
   \def\dododofieldstack##1%
     {\doglobal\increment\stackedfieldnumber
      \fitfield[#1:\stackedfieldnumber]\egroup\bgroup}%
   \startoverlay
     \bgroup
     \globalprocesscommalist[#2]\dododofieldstack
     \egroup
   \stopoverlay
   \endgroup}

%D When submitting a form, we need to tell the driver module
%D that we want \FDF\ or \HTML.

\newtoks\everysetupforms

\unexpanded\def\setupforms{\dosingleempty\dosetupforms}

\def\dosetupforms[#1]
  {\getparameters[\??fr][#1]%
   \the\everysetupforms}

\appendtoks
    \ctxlua{backends.codeinjections.setformsmethod("@@frmethod")}%
\to \everysetupforms

\setupforms
  [\c!method=XML] % no need for everyjob initialization as this is the default

%D Goodie: (unchecked in \MKIV)

\unexpanded\def\definepushbutton % name optional setup
  {\dodoubleempty\dodefinepushbutton}

\def\dodefinepushbutton[#1][#2]% name setup
  {\dododefinepushbutton{#1}{n}{push}%
   \dododefinepushbutton{#1}{r}{\symbol[psym:#1:n]}%
   \dododefinepushbutton{#1}{d}{\symbol[psym:#1:r]}%
   \setvalue{pushbutton:#1}{\dohandlepushbutton{#1}{#2}}}

\def\dododefinepushbutton#1#2#3%
  {\doifsymboldefinedelse{psym:#1:#2}%
     \donothing{\definesymbol[psym:#1:#2][{#3}]}}

\unexpanded\def\definepushsymbol
  {\dotripleargument\dodefinepushsymbol}

\def\dodefinepushsymbol[#1][#2]% [#3]
  {\definesymbol[psym:#1:#2]}

\def\dopushbutton[#1][#2]%
  {\executeifdefined{pushbutton:#1}\gobbleoneargument{#2}}

\def\pushbutton
  {\dodoubleargument\dopushbutton}

\def\dohandlepushbutton#1#2#3% identifier setup script
  {\bgroup
   \nextsystemfield
   \setupfield
     [pushbutton]
     [\c!frame=\v!overlay,
      \c!offset=\v!overlay,
      \c!clickout=#3,#2]%
   \definefield
     [\currentsystemfield]
     [push]
     [pushbutton]
     [psym:#1:n,psym:#1:r,psym:#1:d]%
   \fitfield
     [\currentsystemfield]%
   \egroup}

% \def\menu@psh
%   {\dodoubleargument\domenu@psh}
%
% \def\domenu@psh[#1][#2]#3\\%
%   {\txt\pushbutton[#1][#2]\\}%
%
%\appendtoks \let\psh\do@@ampsh \to \everysetmenucommands

\unexpanded\def\menu@psh{\txt\pushbutton}

\appendtoks \let\psh\menu@psh \to \everysetmenucommands

% \definepushbutton [reset]
%
% \definepushsymbol [reset] [n] [\uniqueMPgraphic{whatever}{color=green}]
% \definepushsymbol [reset] [r] [\uniqueMPgraphic{whatever}{color=white}]
%
% \startinteractionmenu[bottom]
%   \psh [reset] [JS(reset_something)] \\
% \stopinteractionmenu

%D Another goodie: (unchecked in \MKIV)

% \definecolor[rollover:n][red]
% \definecolor[rollover:r][green]
% \definecolor[rollover:d][blue]

\definepalet
  [rollover]
  [n=red,
   r=green,
   d=blue]

\newcounter\nofrollovers
\newcounter\nofrollbuttons

\def\dorollbutton[#1][#2]#3[#4]%
  {\dontleavehmode
   \bgroup
   \doglobal\increment\nofrollovers
   \doglobal\increment\nofrollbuttons
   \unexpanded\def\dosetlocationbox[##1]##2[##3]%
     {\getparameters[##1][##3]%
      \definecolor[rollover][rollover:##2]%
      \doifelse{##2}{n}{\doifelsevalue{##1\c!alternative}\v!hidden\phantom\hbox}\hbox
        {\localframed[##1]
           [\c!framecolor=rollover,\c!backgroundcolor=rollover,\c!color=rollover]%
           {\dolocationattributes{##1}\c!style\c!color{#3}}}}%
   \iffirstargument
     \ifsecondargument
       \def\setlocationbox##1{\dosetlocationbox[\??am#1]{##1}[#2]}%
     \else
       \doifassignmentelse{#1}
         {\def\setlocationbox##1{\dosetlocationbox[\??bt]{##1}[#1]}}
         {\def\setlocationbox##1{\dosetlocationbox[\??am#1]{##1}[]}}%
     \fi
   \else
     \def\setlocationbox##1{\dosetlocationbox[\??bt]{##1}[]}%
   \fi
   % todo: share symbols, tricky since different dimensions
   \definesymbol[rsym:\nofrollovers:n][\setlocationbox n]%
   \definesymbol[rsym:\nofrollovers:r][\setlocationbox r]%
   \definesymbol[rsym:\nofrollovers:d][\setlocationbox d]%
   \setupfield
     [rollbutton]
     [\c!frame=\v!off,
      \c!offset=\v!overlay,
      \c!clickout={#4}]%
   \definefield
     [roll:\nofrollbuttons][push][rollbutton]
     [rsym:\nofrollovers:n,%
      rsym:\nofrollovers:r,%
      rsym:\nofrollovers:d]%
   \fitfield[roll:\nofrollbuttons]%
   \egroup}

\unexpanded\def\rollbutton
  {\dodoubleempty\dorollbutton}

\def\menu@rob[#1]#2\\%
  {\txt\rollbutton[\currentmenu]{\ignorespaces#2\unskip}[#1]\\}%

\appendtoks \let\rob\menu@rob \to \everysetmenucommands

% calls:
%              {..} [JS..]
% [left]       {..} [JS..]
%        [a=b] {..} [JS..]
% [left] [a=b] {..} [JS..]
%
% \setupbuttons[offset=0pt,frame=off] % alternative=hidden
%
% \rollbutton {Manuals}       [JS(Goto_File{show-man.pdf})]
% \rollbutton {Articles}      [JS(Goto_File{show-art.pdf})]
% \rollbutton {Papers}        [JS(Goto_File{show-pap.pdf})]
% \rollbutton {Presentations} [JS(Goto_File{show-pre.pdf})]
% \rollbutton {Resources}     [JS(Goto_File{show-res.pdf})]
%
% \rob [JS(...)] bla bla \\

\unexpanded\def\overlayrollbutton
  {\dodoubleargument\dooverlayrollbutton}

\def\dooverlayrollbutton[#1][#2]%
  {\bgroup
   \nextsystemfield
   \setupfield
     [overlayrollbutton]
     [\c!frame=\v!off,\c!offset=\v!overlay,\c!regionin={#1},\c!regionout={#2}]%
   \definesymbol
     [\currentsystemfield]
     [{\framed[\c!frame=\v!off,\c!width=\overlaywidth,\c!height=\overlayheight]{}}]%
   \definefield
     [\currentsystemfield][push][overlayrollbutton][\currentsystemfield][\currentsystemfield]%
   \fitfield[\currentsystemfield]%
   \egroup}

% \defineoverlay
%   [ShowMenu]
%   [{\overlayrollbutton[VideLayer{navigation}][HideLayer{navigation}]}]

\protect \endinput