%D \module
%D   [       file=font-sty,
%D        version=2011.01.13, % (copied fron font-ini)
%D          title=\CONTEXT\ Font Macros,
%D       subtitle=features,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%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 Font Macros / Features}

\unprotect

%D Feature management.
%D
%D \starttyping
%D \definefontfeature[smallcaps][smcp=yes,script=latn]
%D \definefontfeature[smallcaps][SmallCapitals=yes,script=latn]
%D \definefontfeature[smallcaps][Small Capitals=yes,script=latn]
%D \definefontfeature[smallcaps][small capitals=yes,script=latn]
%D \definefontfeature[smallcaps][smallcapitals=yes,script=latn]
%D
%D \definedfont[cambria*smallcaps] test
%D
%D \starttext
%D \definefontfeature[basekerned][default][mode=base]
%D \definefontfeature[nodekerned][default][mode=node]
%D \definefontfeature[nonekerned][default][mode=base,kern=no]
%D \setupcolors[state=start]
%D \startoverlay
%D     {\vbox{\red  \definedfont[Serif*nonekerned at 12pt]\input tufte }}
%D     {\vbox{\blue \definedfont[Serif*basekerned at 12pt]\input tufte }}
%D     {\vbox{\green\definedfont[Serif*nodekerned at 12pt]\input tufte }}
%D \stopoverlay
%D \stoptext
%D
%D \enabletrackers[otf.kerns]
%D
%D \definefontfeature[withkern][default][mode=node]
%D \definefontfeature[nokern]  [default][mode=node,kern=no]
%D \definefontfeature[single]  [default][mode=node,cpsp=yes]
%D \definefontfeature[simple]  [default][mode=node,cpsp=yes,kern=no]
%D
%D {\definedfont[Serif*default] [FGFGFGFGFGFGFGFGFGFGFGFGFG ABCDEFGHIJKLMNOPQRSTUVWXYZ] \par}
%D {\definedfont[Serif*nokern]  [FGFGFGFGFGFGFGFGFGFGFGFGFG ABCDEFGHIJKLMNOPQRSTUVWXYZ] \par}
%D {\definedfont[Serif*single]  [FGFGFGFGFGFGFGFGFGFGFGFGFG ABCDEFGHIJKLMNOPQRSTUVWXYZ] \par}
%D {\definedfont[Serif*simple]  [FGFGFGFGFGFGFGFGFGFGFGFGFG ABCDEFGHIJKLMNOPQRSTUVWXYZ] \par}
%D \stoptyping

% \definefontfeature[slanted]  [default][slant=.25]
% \definefontfeature[stretched][default][stretch=2]
%
% \start \definedfont[SerifBold*slanted   at 20pt] \ruledhbox{Test!} \stop
% \start \definedfont[SerifBold*stretched at 20pt] \ruledhbox{Test!} \stop
%
% \definefontfeature[default]     [liga=yes,texligatures=yes,texquotes=yes]
% \definefontfeature[default-caps][liga=yes,texligatures=yes,texquotes=yes,smcp=yes,script=latn]
%
% \starttypescript [serif] [palatino-nova-regular] [name]
%     \definefontsynonym[Serif]    [palatinonova-regular][features=default]
%     \definefontsynonym[SerifCaps][palatinonova-regular][features=default-caps] % also sets Serif
% \stoptypescript
%
% \starttypescript [serif] [palatino-nova-regular] [name]
%     \definefontsynonym[Serif]          [palatinonova-regular*default]
%     \definefontsynonym[SerifCaps]      [palatinonova-regular*default-caps]
% \stoptypescript
%
% \definetypeface[mainface][rm][serif][palatino-nova-regular][default] \setupbodyfont[mainface]
%
% \starttext
%   ``Test'' -- --- ff fi fl \sc ``Test'' -- --- ff fi fl
% \stoptext
%
% \definefontfeature
%   [default-base]
%   [script=latn,language=dflt,liga=yes,kern=yes,tlig=yes,trep=yes]
% \definefontfeature
%   [default-node]
%   [script=latn,language=dflt,liga=yes,kern=yes,tlig=yes,trep=yes,mode=node]
% \definefontfeature
%   [default-none]
%   [script=latn,language=dflt,liga=yes,kern=no, tlig=yes,trep=yes]
%
% \startoverlay
%     {\vtop{\color[red]  {\font\test=name:lmroman12regular*default-node \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[green]{\font\test=name:lmroman12regular*default-base \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[blue] {\font\test=name:lmroman12regular*default-none \test \input ward \input zapf \input linden }}}
% \stopoverlay
%
% \blank
%
% \startoverlay
%     {\vtop{\color[red]  {\font\test=name:texgyrepagella*default-node \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[green]{\font\test=name:texgyrepagella*default-base \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[blue] {\font\test=name:texgyrepagella*default-none \test \input ward \input zapf \input linden }}}
% \stopoverlay
%
% \blank
%
% \startoverlay
%     {\vtop{\color[red]  {\font\test=name:palatinonovaregular*default-node \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[green]{\font\test=name:palatinonovaregular*default-base \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[blue] {\font\test=name:palatinonovaregular*default-none \test \input ward \input zapf \input linden }}}
% \stopoverlay
%
% \startoverlay
%     {\vtop{\color[red]  {\font\test=name:OfficinaSerifBookITC*default-node \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[green]{\font\test=name:OfficinaSerifBookITC*default-base \test \input ward \input zapf \input linden }}}
%     {\vtop{\color[blue] {\font\test=name:OfficinaSerifBookITC*default-none \test \input ward \input zapf \input linden }}}
% \stopoverlay
%
% \definefontfeature[superdefault][default][compose=yes]
%
% {\font\oeps=name:lmroman10regular*default      at 30pt \oeps test \char7683}
% {\font\oeps=name:lmroman10regular*superdefault at 30pt \oeps test \char7683}

\unexpanded\def\definefontfeature
  {\dotripleargument\font_basics_define_font_feature}

\def\font_basics_define_font_feature[#featureset][#parent][#settings]%
  {\clf_definefontfeature{#featureset}{#parent}{#settings}}

\unexpanded\def\adaptfontfeature
  {\dodoubleargument\font_basics_adapt_font_feature}

\def\font_basics_adapt_font_feature[#pattern][#settings]%
  {\clf_adaptfontfeature{#pattern}{#settings}}

\unexpanded\def\fontfeatureslist
  {\dodoubleargument\font_basics_features_list}

\def\font_basics_features_list[#name][#separator]% todo: arg voor type
  {\clf_featurelist{#name}{\detokenize{#separator}}}

\attribute\zerocount\zerocount % first in list, so fast match

\prependtoks
    \attribute\zerocount\attributeunsetvalue % new per 2017-08-30
\to \t_attr_list_local

% beware: these are global features on top of existing font features

\let\currentfeature      \s!current
\let\m_font_feature_list \s!current
\let\m_font_feature_asked\empty

\newconstant\c_font_feature_state

% hashing at this end is slower

\unexpanded\def\addfeature        {\doifelsenextoptionalcs\font_feature_add_yes      \font_feature_add_nop      }
\unexpanded\def\subtractfeature   {\doifelsenextoptionalcs\font_feature_subtract_yes \font_feature_subtract_nop }
\unexpanded\def\replacefeature    {\doifelsenextoptionalcs\font_feature_replace_yes  \font_feature_replace_nop  }
\unexpanded\def\resetandaddfeature{\doifelsenextoptionalcs\font_feature_reset_add_yes\font_feature_reset_add_nop}
\unexpanded\def\feature           {\doifelsenextoptionalcs\font_feature_yes          \font_feature_nop          }

\unexpanded\def\font_feature_add_yes      [#feature]{\edef\m_font_feature_asked{#feature}\font_feature_add}
\unexpanded\def\font_feature_add_nop        #feature{\edef\m_font_feature_asked{#feature}\font_feature_add}

\unexpanded\def\font_feature_subtract_yes [#feature]{\edef\m_font_feature_asked{#feature}\font_feature_subtract}
\unexpanded\def\font_feature_subtract_nop   #feature{\edef\m_font_feature_asked{#feature}\font_feature_subtract}

\unexpanded\def\font_feature_replace_yes  [#feature]{\edef\m_font_feature_asked{#feature}\font_feature_replace}
\unexpanded\def\font_feature_replace_nop    #feature{\edef\m_font_feature_asked{#feature}\font_feature_replace}

\unexpanded\def\font_feature_reset_add_yes[#feature]{\edef\m_font_feature_asked{#feature}\font_feature_reset_add}
\unexpanded\def\font_feature_reset_add_nop  #feature{\edef\m_font_feature_asked{#feature}\font_feature_reset_add}

\let\doaddfeature        \font_feature_add_nop       % low level faster ones
\let\dosubtractfeature   \font_feature_subtract_nop
\let\doreplacefeature    \font_feature_replace_nop
\let\doresetandaddfeature\font_feature_reset_add_nop

\unexpanded\def\font_feature_add
  {\ifnum\c_font_feature_state=\plusone
     \ifx\m_font_feature_asked\currentfeature\else
       \font_feature_add_indeed
     \fi
   \else
     \font_feature_add_indeed
   \fi}

\unexpanded\def\font_feature_add_indeed
  {\clf_addfeature{\m_font_feature_list}{\m_font_feature_asked}%
   \edef\m_font_feature_list{\m_font_feature_list+\m_font_feature_asked}% also + at the lua end
   \c_font_feature_state\plusone
   \let\currentfeature\m_font_feature_asked}

\unexpanded\def\font_feature_subtract
  {\ifnum\c_font_feature_state=\minusone
     \ifx\m_font_feature_asked\currentfeature\else
       \font_feature_subtract_indeed
     \fi
   \else
     \font_feature_subtract_indeed
   \fi}

\unexpanded\def\font_feature_subtract_indeed
  {\clf_subtractfeature{\m_font_feature_list}{\m_font_feature_asked}%
   \edef\m_font_feature_list{\m_font_feature_list-\m_font_feature_asked}% also - at the lua end
   \c_font_feature_state\minusone
   \let\currentfeature\m_font_feature_asked}

\unexpanded\def\font_feature_replace
  {\ifnum\c_font_feature_state=\zerocount
     \ifx\m_font_feature_asked\currentfeature\else
       \font_feature_replace_indeed
     \fi
   \else
     \font_feature_replace_indeed
   \fi}

\unexpanded\def\font_feature_replace_indeed
  {\clf_replacefeature{\m_font_feature_list}{\m_font_feature_asked}%
   \edef\m_font_feature_list{\m_font_feature_list=\m_font_feature_asked}% also = at the lua end
   \c_font_feature_state\zerocount
   \let\currentfeature\m_font_feature_asked}

\unexpanded\def\resetfeature
  {\ifx\currentfeature\s!current \else
     \font_feature_reset_indeed
   \fi}

\unexpanded\def\font_feature_reset_indeed
  {\let\m_font_feature_asked\empty
   \let\currentfeature      \s!current
   \let\m_font_feature_list \s!current
   \clf_resetfeature}

\unexpanded\def\revivefeature
  {\ifx\currentfeature\s!current \else
     \font_feature_revive_indeed
   \fi}

\unexpanded\def\font_feature_revive_indeed
  {\clf_revivefeature{\m_font_feature_list}}

\unexpanded\def\font_feature_reset_add
  {\ifnum\c_font_feature_state=\plusone
     \ifx\m_font_feature_asked\currentfeature\else
       \font_feature_reset_add_indeed
     \fi
   \else
     \font_feature_reset_add_indeed
   \fi}

\unexpanded\def\font_feature_reset_add_indeed
  {\clf_addfeature{\s!current}{\m_font_feature_asked}%
   \edef\m_font_feature_list{\s!current+\m_font_feature_asked}% also + at the lua end
   \c_font_feature_state\plusone
   \let\currentfeature\m_font_feature_asked}

\installcorenamespace{featureyes}
\installcorenamespace{featurenop}

%\unexpanded\def\font_feature_yes[#method]{\csname\??featureyes\ifcsname\??featureyes#method\endcsname#method\else\s!unknown\fi\endcsname}
%\unexpanded\def\font_feature_nop  #method{\csname\??featurenop\ifcsname\??featurenop#method\endcsname#method\else\s!unknown\fi\endcsname}

\unexpanded\def\font_feature_yes[#method]{\begincsname\??featureyes#method\endcsname}
\unexpanded\def\font_feature_nop  #method{\begincsname\??featurenop#method\endcsname}

\letvalue{\??featureyes +}\addfeature
\letvalue{\??featurenop +}\addfeature
\letvalue{\??featureyes -}\subtractfeature
\letvalue{\??featurenop -}\subtractfeature
\letvalue{\??featureyes =}\replacefeature
\letvalue{\??featurenop =}\replacefeature
\letvalue{\??featureyes !}\resetandaddfeature
\letvalue{\??featurenop !}\resetandaddfeature
\letvalue{\??featureyes >}\revivefeature
\letvalue{\??featurenop >}\revivefeature
\letvalue{\??featureyes <}\resetfeature
\letvalue{\??featurenop <}\resetfeature

\letvalue{\??featureyes\v!more   }\addfeature      % add set to previous set and combine with font set
\letvalue{\??featurenop\v!more   }\addfeature
\letvalue{\??featureyes\v!less   }\subtractfeature % subtract set from previous set and combine with font set
\letvalue{\??featurenop\v!less   }\subtractfeature
\letvalue{\??featureyes\v!new    }\replacefeature  % replace font set
\letvalue{\??featurenop\v!new    }\replacefeature
\letvalue{\??featureyes\v!reset  }\resetfeature    % forget sets and revert to font set
\letvalue{\??featurenop\v!reset  }\resetfeature
\letvalue{\??featureyes\v!default}\revivefeature   % make sure the current set is used on top of the font set
\letvalue{\??featurenop\v!default}\revivefeature
\letvalue{\??featureyes\v!old    }\revivefeature
\letvalue{\??featurenop\v!old    }\revivefeature
\letvalue{\??featureyes\v!local  }\resetandaddfeature
\letvalue{\??featurenop\v!local  }\resetandaddfeature
\letvalue{\??featureyes\s!unknown}\empty
\letvalue{\??featurenop\s!unknown}\empty

% experimental bonus:

% \unexpanded\def\addfflanguage
%   {\ifnum\c_font_feature_state=\plusone
%      \ifx\currentlanguage\currentfeature\else
%        \font_feature_add_language_indeed
%      \fi
%    \else
%      \font_feature_add_language_indeed
%    \fi}
%
% \unexpanded\def\font_feature_add_language_indeed
%   {\clf_addfeature{\m_font_feature_list}{\currentlanguage}%
%    \edef\m_font_feature_list{\m_font_feature_list+\currentlanguage}% also + at the lua end
%    \c_font_feature_state\plusone
%    \let\currentfeature\currentlanguage}
%
% some 3% slower:

% \unexpanded\def\addfflanguage
%   {\let\m_font_feature_asked\currentlanguage
%    \font_feature_add}

\let\m_font_feature_language\currentlanguage

\unexpanded\def\addfflanguage
  {\ifx\currentlanguage\m_font_feature_language\else
     \let\m_font_feature_language\currentlanguage
     \let\m_font_feature_asked   \currentlanguage
     \font_feature_add
   \fi}

% just for old times sake:

\unexpanded\def\featureattribute#feature%
  {\clf_featureattribute{#feature}}

\unexpanded\def\setfontfeature#feature%
  {\edef\currentfeature{#feature}%
   \let\m_font_feature_list\currentfeature
   \clf_setfontfeature{\currentfeature}}

\let\resetfontfeature\resetfeature

%  these are obsolete (don't use them any longer)

\let\addfontfeaturetoset        \font_feature_add_nop
\let\subtractfontfeaturefromset \font_feature_subtract_nop
\let\addfontfeaturetofont       \font_feature_add_nop
\let\subtractfontfeaturefromfont\font_feature_subtract_nop

\let\setff\setfontfeature
\let\addfs\addfontfeaturetoset
\let\subfs\subtractfontfeaturefromset
\let\addff\addfontfeaturetofont
\let\subff\subtractfontfeaturefromfont

%D \macros
%D   {os}
%D
%D In good old \TEX, the old style numerals were often taken
%D from the math fonts. No longer.

\definefontfeature
  [just-os]
  [mode=node,onum=yes]

%unexpanded\def\sc{\setfontfeature{smallcaps}}
\unexpanded\def\os{\setfontfeature{just-os}}

% \doifelsecurrentfonthasfeature{smcp}{YES}{NO}
% \doifelsecurrentfonthasfeature{crap}{YES}{NO}
% \doifelsecurrentfonthasfeature{kern}{YES}{NO}

\def\doifelsecurrentfonthasfeature#feature% expandable
  {\clf_doifelsecurrentfonthasfeature{#feature}}

\let\doifcurrentfonthasfeatureelse\doifelsecurrentfonthasfeature

\def\doifelsefontfeature#feature% expandable
  {\clf_doifelsefontfeature{#feature}}

\let\doiffontfeatureelse\doifelsefontfeature

\def\doifunknownfontfeature#feature% expandable
  {\clf_doifunknownfontfeature{#feature}}

% new:

\clf_registerlanguagefeatures

% also new

\unexpanded\def\useaddfontfeatureparameter#namespace% faster local variant
  {\edef\m_font_feature_asked{#namespace\c!features}%
   \ifx\m_font_feature_asked\empty\else
     \font_feature_add
   \fi}

% let's put this here:

\unexpanded\def\slashedzero
  {\dontleavehmode
   \begingroup
  %\addff{zero}
   \font_feature_add_nop{zero}%
   0%
   \endgroup}

% not nice but maybe handy

% \starttyping
% \blockligatures[fi,ff] \blockligatures[fl]
%
% \definefontfeature[default:b][default][blockligatures=yes]
%
% \setupbodyfont[pagella] \showfontkerns
%
% \definedfont[Serif*default:b]
%
% \startTEXpage[offset=1em]
%     fi ff fl
% \stopTEXpage
% \stoptyping

\unexpanded\def\blockligatures[#1]{\clf_blockligatures{#1}}

\protect \endinput
