%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}{1.001}

\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}}

% \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}}

\def\expdoifcommonelse\expdoifelsecommon
\def\expdoifinsetelse \expdoifelseinset

% we define these here, just in case ...

\def\luastringsep{===} % this permits \typefile{self} otherwise nested b/e sep problems

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

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

% A handy helper:

% \def\luaexpr#1{\ctxlua{context(tostring(#1))}} % more efficient:

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

\def\luaexpr#1{\ctxlua{tex.print(tostring(#1))}} % no use is shortcutting has to be compiled

% helpers:

\def\ui_fo  #1{#1}
\def\ui_go  #1{}
\def\ui_ft#1#2{#1}
\def\ui_st#1#2{#2}

%D Let's bring this under \LUA\ (and therefore \MKIV\ sandbox) control:

% \setnewconstant\c_syst_write 18
%
% \unexpanded\def\write#1#% so we can handle \immediate
%   {\ifnum#1=\c_syst_write
%      \expandafter\syst_execute
%    \else
%      \normalwrite#1%
%    \fi}
%
% \unexpanded\def\syst_execute#1%
%   {\ctxlua{os.execute(\!!bs#1\!!es)}}

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

% Nicer would be if we could just disable write 18 and keep os.execute
% which in fact we can do by defining write18 as macro instead of
% primitive ... todo.

% \unexpanded\def\write#1#%
%   {\syst_write{#1}}
%
% \def\syst_write#1#2%
%   {\ctxcommand{write(\number#1,\!!bs\normalunexpanded{#2}\!!es)}}
%
% \unexpanded\def\writeviatex#1#2%
%   {\ifx\normalwrite\relax\else
%      \normalwrite#1{#2}%
%    \fi}

% we have no way yet to pickup \immediate unless we redefine it
% we assume immediate execution

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

\unexpanded\def\write#1#%
  {\ifnum#1=18
     \expandafter\syst_write_execute
   \else
     \normalwrite#1%
   \fi}

\protect \endinput