%D \module
%D   [       file=syst-lua,
%D        version=2008.01.25,
%D          title=\CONTEXT\ System Macros,
%D       subtitle=Helper macros based on \LUA,
%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.

\registerctxluafile{syst-lua}{}

\unprotect

\def\expdoifelse#1#2{\clf_doifelsesame{#1}{#2}}
\def\expdoif    #1#2{\clf_doifsame    {#1}{#2}}
\def\expdoifnot #1#2{\clf_doifnotsame {#1}{#2}}

%D Here is variant using a brainwave of the 12\high{+} hour \quotation {Long Road
%D Out of Eden}\footnote {Eden being Backo\TeX\ 2018, where the virtues of the \type
%D {\expanded} primitive were mentioned in talks.} trip. For now I don't really see
%D other useful applications.

\def\expandeddoifelse#1#2%
  {\immediateassignment\edef\m_syst_string_one{#1}%
   \immediateassignment\edef\m_syst_string_two{#2}%
   \ifx\m_syst_string_one\m_syst_string_two
     \expandafter\firstoftwoarguments
   \else
     \expandafter\secondoftwoarguments
   \fi}

\def\expandeddoif#1#2%
  {\immediateassignment\edef\m_syst_string_one{#1}%
   \immediateassignment\edef\m_syst_string_two{#2}%
   \ifx\m_syst_string_one\m_syst_string_two
     \expandafter\firstofoneargument
   \else
     \expandafter\gobbleoneargument
   \fi}

\def\expandeddoifnot#1#2%
  {\immediateassignment\edef\m_syst_string_one{#1}%
   \immediateassignment\edef\m_syst_string_two{#2}%
   \ifx\m_syst_string_one\m_syst_string_two
     \expandafter\gobbleoneargument
   \else
     \expandafter\firstofoneargument
   \fi}

% \testfeatureonce{100000}{\doifelse{hello world}{here i am}{}}           % 0.3
% \testfeatureonce{100000}{\expandabledoifelse{hello world}{here i am}{}} % 1.5

\def\expdoifelsecommon#1#2{\clf_doifelsecommon{#1}{#2}}
\def\expdoifelseinset #1#2{\clf_doifelseinset {#1}{#2}}

\let\expdoifcommonelse\expdoifelsecommon
\let\expdoifinsetelse \expdoifelseinset

%D We define these here, just in case. This permits \typefile {self} otherwise
%D nested b|/|e sep problems.

\def\luastringsep{===}

\edef\!!bs{[\luastringsep[}
\edef\!!es{]\luastringsep]}

\protected\def\writestatus#1#2{\clf_writestatus{#1}{#2}}

%D We can omit the tex.ctxcatcodes here as nowadays we seldom change the regime at
%D the \TEX\ end:

%def\luaexpr#1{\ctxlua{context  (tostring(#1))}} % more efficient:
\def\luaexpr#1{\ctxlua{tex.print(tostring(#1))}} % no use in shortcutting has to be compiled

%D But as we only use write 16 we could as well do all in \LUA\ and ignore the rest.
%D Okay, we still can do writes here but only when not blocked.

\let\syst_write_execute\clf_execute % always {...}

%D There is a probably rather useless \type {\expression} command that can mix \LUA\ numeric
%D expressions with \TEX\ commands (for as far that makes sense) that works like this:
%D
%D \starttyping
%D \mathchardef\foooo   1234
%D \def        \mymacro {123.45}
%D \scratchdimen 123pt
%D \scratchskip  123pt
%D \scratchtoks  {34}
%D
%D \testfeatureonce{10000}{\edef\foo{\expression
%D     round(
%D         12.3 * \scratchdimen
%D       - (12.3 * \scratchskip) / 2
%D       + 2 ^ 3
%D       * (
%D           - sqrt(12)
%D           - 10pt
%D           - \foooo
%D           + \luatexversion
%D           - \mymacro
%D           + \scratchtoks
%D           + \the\scratchcounter
%D           + \number\scratchcounter
%D         )
%D     )
%D \relax}}
%D
%D \expression string.format("\letterpercent f",\elapsedtime/50000) \relax
%D \stoptyping
%D
%D The final \type {\relax} is mandate because we also accept spaces. Of course we
%D could have avoided it by using outer parenthesis but this is cleaner anyway.
%D
%D The \MKIV\ version is a bit more limited than the \LMTX\ version because it only
%D supports the standard math functions.

% maybe: \let\texexpr\expression

\protect \endinput
