% \iffalse meta-comment
%
%% File: l3luatex.dtx Copyright (C) 2010-2017 The LaTeX3 Project
%
% It may be distributed and/or modified under the conditions of the
% LaTeX Project Public License (LPPL), either version 1.3c of this
% license or (at your option) any later version.  The latest version
% of this license is in the file
%
%    http://www.latex-project.org/lppl.txt
%
% This file is part of the "l3kernel bundle" (The Work in LPPL)
% and all files in that bundle must be distributed together.
%
% -----------------------------------------------------------------------
%
% The development version of the bundle can be found at
%
%    https://github.com/latex3/latex3
%
% for those people who are interested.
%
%<*driver>
\documentclass[full]{l3doc}
\begin{document}
  \DocInput{\jobname.dtx}
\end{document}
%</driver>
% \fi
%
% \title{^^A
%   The \pkg{l3luatex} package\\LuaTeX-specific functions^^A
% }
%
% \author{^^A
%  The \LaTeX3 Project\thanks
%    {^^A
%      E-mail:
%        \href{mailto:latex-team@latex-project.org}
%          {latex-team@latex-project.org}^^A
%    }^^A
% }
%
% \date{Released 2017/09/18}
%
% \maketitle
%
% \begin{documentation}
%
% \section{Breaking out to \Lua{}}
%
% The \LuaTeX{} engine provides access to the \Lua{} programming language,
% and with it access to the \enquote{internals} of \TeX{}. In order to use
% this within the framework provided here, a family of functions is
% available. When used with \pdfTeX{} or \XeTeX{} these raise an
% error: use \cs{sys_if_engine_luatex:T} to avoid this. Details on using
% \Lua{} with the \LuaTeX{} engine are given in the \LuaTeX{} manual.
%
% \subsection{\TeX{} code interfaces}
%
% \begin{function}[EXP, added = 2015-06-29]{\lua_now_x:n, \lua_now:n}
%   \begin{syntax}
%     \cs{lua_now:n} \Arg{token list}
%   \end{syntax}
%   The \meta{token list} is first tokenized by \TeX{}, which includes
%   converting line ends to spaces in the usual \TeX{} manner and which
%   respects currently-applicable \TeX{} category codes. The resulting
%   \meta{\Lua{} input} is passed to the \Lua{} interpreter for processing.
%   Each \cs{lua_now:n} block is treated by \Lua{} as a separate chunk.
%   The \Lua{} interpreter executes the \meta{\Lua{} input} immediately,
%   and in an expandable manner.
%
%   In the case of the \cs{lua_now_x:n} version the input is fully expanded
%   by \TeX{} in an \texttt{x}-type manner \emph{but} the function remains
%   fully expandable.
%   \begin{texnote}
%     \cs{lua_now_x:n} is a macro wrapper around \tn{directlua}: when
%     \LuaTeX{} is in use two expansions are required to yield the
%     result of the \Lua{} code.
%   \end{texnote}
% \end{function}
%
% \begin{function}[added = 2015-06-30]{\lua_shipout_x:n, \lua_shipout:n}
%   \begin{syntax}
%     \cs{lua_shipout:n} \Arg{token list}
%   \end{syntax}
%   The \meta{token list} is first tokenized by \TeX{}, which includes
%   converting line ends to spaces in the usual \TeX{} manner and which
%   respects currently-applicable \TeX{} category codes.  The resulting
%   \meta{\Lua{} input} is passed to the \Lua{} interpreter when the
%   current page is finalised (\emph{i.e.}~at shipout).  Each
%   \cs{lua_shipout:n} block is treated by \Lua{} as a separate chunk.
%   The \Lua{} interpreter will execute the \meta{\Lua{} input} during the
%   page-building routine: no \TeX{} expansion of the \meta{\Lua{} input}
%   will occur at this stage.
%
%   In the case of the \cs{lua_shipout_x:n} version the input is fully
%   expanded by \TeX{} in an \texttt{x}-type manner during the shipout
%   operation.
%   \begin{texnote}
%     At a \TeX{} level, the \meta{\Lua{} input} is stored as a
%     \enquote{whatsit}.
%   \end{texnote}
% \end{function}
%
% \begin{function}[EXP, added = 2015-06-29]{\lua_escape_x:n, \lua_escape:n}
%   \begin{syntax}
%     \cs{lua_escape:n} \Arg{token list}
%   \end{syntax}
%   Converts the \meta{token list} such that it can safely be passed to
%   \Lua{}: embedded backslashes, double and single quotes, and newlines
%   and carriage returns are escaped. This is done by prepending an extra
%   token consisting of a backslash with category code~$12$, and for the line
%   endings, converting them to |\n| and |\r|, respectively.
%
%   In the case of the \cs{lua_escape_x:n} version the input is fully expanded
%   by \TeX{} in an \texttt{x}-type manner \emph{but} the function remains
%   fully expandable.
%   \begin{texnote}
%     \cs{lua_escape_x:n} is a macro wrapper around \tn{luaescapestring}:
%     when \LuaTeX{} is in use two expansions are required to yield the
%     result of the \Lua{} code.
%   \end{texnote}
% \end{function}
%
% \subsection{Lua interfaces}
%
% As well as interfaces for \TeX{}, there are a small number of Lua functions
% provided here. Currently these are intended for internal use only.
%
% \begin{function}{l3kernel.charcat}
%   \begin{syntax}
%     \cs{l3kernel.charcat}|(|\meta{charcode}, \meta{catcode}|)|
%   \end{syntax}
%   Constructs a character of \meta{charcode} and \meta{catcode} and returns
%   the result to \TeX{}.
% \end{function}
%
% \begin{function}{l3kernel.filemdfivesum}
%   \begin{syntax}
%     \cs{l3kernel.filemdfivesum}|(|\meta{file}|)|
%   \end{syntax}
%   Returns the of the MD5 sum of the file contents read as bytes. If the
%   \meta{file} is not found, nothing is returned with \emph{no error raised}.
% \end{function}
%
% \begin{function}{l3kernel.filemoddate}
%   \begin{syntax}
%     \cs{l3kernel.filemoddate}|(|\meta{file}|)|
%   \end{syntax}
%   Returns the of the date/time of last modification of the \meta{file} in the
%   format |D:|\meta{year}\meta{month}\meta{day}\meta{hour}\meta{minute}^^A
%   \meta{second}\meta{offset}, where the latter may be |Z| (UTC) or
%   \meta{plus-minus}\meta{hours}|'|\meta{minutes}|'|. If the \meta{file} is
%   not found, nothing is returned with \emph{no error raised}.
% \end{function}
%
% \begin{function}{l3kernel.filesize}
%   \begin{syntax}
%     \cs{l3kernel.filesize}|(|\meta{file}|)|
%   \end{syntax}
%   Returns the size of the \meta{file} in bytes. If the \meta{file} is not
%   found, nothing is returned with \emph{no error raised}.
% \end{function}
%
% \begin{function}{l3kernel.strcmp}
%   \begin{syntax}
%     \cs{l3kernel.strcmp}|(|\meta{str one}, \meta{str two}|)|
%   \end{syntax}
%   Compares the two strings and returns |0| to \TeX{}
%   if the two are identical.
% \end{function}
%
% \end{documentation}
%
% \begin{implementation}
%
% \section{\pkg{l3luatex} implementation}
%
%    \begin{macrocode}
%<*initex|package>
%    \end{macrocode}
%
% \subsection{Breaking out to \Lua{}}
%
%    \begin{macrocode}
%<*tex>
%    \end{macrocode}
%
% \begin{macro}[EXP]{\lua_now_x:n, \lua_now:n}
% \begin{macro}{\lua_shipout_x:n, \lua_shipout:n}
% \begin{macro}[EXP]{\lua_escape_x:n, \lua_escape:n}
%   Wrappers around the primitives. As with engines other than \LuaTeX{}
%   these have to be macros, we give them the same status in all cases.
%   When \LuaTeX{} is not in use, simply give an error message/
%    \begin{macrocode}
\cs_new:Npn \lua_now_x:n #1 { \luatex_directlua:D {#1} }
\cs_new:Npn \lua_now:n #1   { \lua_now_x:n { \exp_not:n {#1} } }
\cs_new_protected:Npn \lua_shipout_x:n #1 { \luatex_latelua:D {#1} }
\cs_new_protected:Npn \lua_shipout:n #1
  { \lua_shipout_x:n { \exp_not:n {#1} } }
\cs_new:Npn \lua_escape_x:n #1 { \luatex_luaescapestring:D {#1} }
\cs_new:Npn \lua_escape:n #1 { \lua_escape_x:n { \exp_not:n {#1} } }
\sys_if_engine_luatex:F
  {
    \clist_map_inline:nn
      { \lua_now_x:n , \lua_now:n , \lua_escape_x:n , \lua_escape:n }
      {
        \cs_set:Npn #1 ##1
          {
            \__msg_kernel_expandable_error:nnn
              { kernel } { luatex-required } { #1 }
          }
      }
    \clist_map_inline:nn
      { \lua_shipout_x:n , \lua_shipout:n }
      {
        \cs_set_protected:Npn #1 ##1
          {
            \__msg_kernel_error:nnn
              { kernel } { luatex-required } { #1 }
          }
      }
  }
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{Messages}
%
%    \begin{macrocode}
\__msg_kernel_new:nnnn { kernel } { luatex-required }
  { LuaTeX~engine~not~in~use!~Ignoring~#1. }
  {
    The~feature~you~are~using~is~only~available~
    with~the~LuaTeX~engine.~LaTeX3~ignored~'#1'.
  }
%    \end{macrocode}
%
%    \begin{macrocode}
%</tex>
%    \end{macrocode}
%
% \subsection{\Lua{} functions for internal use}
%
%    \begin{macrocode}
%<*lua>
%    \end{macrocode}
%
% Most of the emulation of \pdfTeX{} here is based heavily on Heiko Oberdiek's
% \pkg{pdftexcmds} package.
%
% \begin{macro}[int]{l3kernel}
%   Create a table for the kernel's own use.
%    \begin{macrocode}
l3kernel = l3kernel or { }
%    \end{macrocode}
% \end{macro}
%
%   Local copies of global tables.
%    \begin{macrocode}
local io      = io
local kpse    = kpse
local lfs     = lfs
local math    = math
local md5     = md5
local os      = os
local string  = string
local tex     = tex
local unicode = unicode
%    \end{macrocode}
%
%   Local copies of standard functions.
%    \begin{macrocode}
local abs        = math.abs
local byte       = string.byte
local floor      = math.floor
local format     = string.format
local gsub       = string.gsub
local kpse_find  = kpse.find_file
local lfs_attr   = lfs.attributes
local md5_sum    = md5.sum
local open       = io.open
local os_date    = os.date
local setcatcode = tex.setcatcode
local str_format = string.format
local sprint     = tex.sprint
local write      = tex.write
local utf8_char  = unicode.utf8.char
%    \end{macrocode}
%
% \begin{macro}[aux]{escapehex}
%   An internal auxiliary to convert a string to the matching hex escape.
%   This works on a byte basis: extension to handled UTF-8 input is
%   covered in \pkg{pdftexcmds} but is not currently required here.
%    \begin{macrocode}
local function escapehex(str)
  write((gsub(str, ".",
    function (ch) return format("%02X", byte(ch)) end)))
end
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{l3kernel.charcat}
%   Creating arbitrary chars needs a category code table. As set up here,
%   one may have been assigned earlier (see \pkg{l3bootstrap}) or a hard-coded
%   one is used. The latter is intended for format mode and should be adjusted
%   to match an eventual allocator.
%    \begin{macrocode}
local charcat_table = l3kernel.charcat_table or 1
local function charcat(charcode, catcode)
  setcatcode(charcat_table, charcode, catcode)
  sprint(charcat_table, utf8_char(charcode))
end
l3kernel.charcat = charcat
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{l3kernel.filemdfivesum}
%   Read an entire file and hash it: the hash function itself is a built-in.
%   As Lua is byte-based there is no work needed here in terms of UTF-8
%   (see \pkg{pdftexcmds} and how it handles strings that have passed through
%   \LuaTeX{}).
%    \begin{macrocode}
local function filemdfivesum(name)
  local file =  kpse_find(name, "tex", true)
  if file then
    local f = open(file, "r")
    if f then
      local data = f:read("*a")
      escapehex(md5_sum(data))
      f:close()
    end
  end
end
l3kernel.filemdfivesum = filemdfivesum
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{l3kernel.filemoddate}
%   See procedure \texttt{makepdftime} in \texttt{utils.c} of
%   \pdfTeX{}.
%    \begin{macrocode}
local function filemoddate(name)
  local file =  kpse_find(name, "tex", true)
  if file then
    local date = lfs_attr(file, "modification")
    if date then
      local d = os_date("*t", date)
      if d.sec >= 60 then
        d.sec = 59
      end
      local u = os_date("!*t", date)
      local off = 60 * (d.hour - u.hour) + d.min - u.min
      if d.year ~= u.year then
        if d.year > u.year then
          off = off + 1440
        else
          off = off - 1440
        end
      elseif d.yday ~= u.yday then
        if d.yday > u.yday then
          off = off + 1440
        else
          off = off - 1440
        end
      end
      local timezone
      if off == 0 then
        timezone = "Z"
      else
        local hours = floor(off / 60)
        local mins  = abs(off - hours * 60)
        timezone = str_format("%+03d", hours)
          .. "'" .. str_format("%02d", mins) .. "'"
      end
      write("D:"
        .. str_format("%04d", d.year)
        .. str_format("%02d", d.month)
        .. str_format("%02d", d.day)
        .. str_format("%02d", d.hour)
        .. str_format("%02d", d.min)
        .. str_format("%02d", d.sec)
        .. timezone)
    end
  end
end
l3kernel.filemoddate = filemoddate
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{l3kernel.filesize}
%   A simple disk lookup.
%    \begin{macrocode}
local function filesize(name)
  local file =  kpse_find(name, "tex", true)
  if file then
    local size = lfs_attr(file, "size")
    if size then
      write(size)
    end
  end
end
l3kernel.filesize = filesize
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}[int]{l3kernel.strcmp}
%   String comparison which gives the same results as \pdfTeX{}'s
%   \tn{pdfstrcmp}, although the ordering should likely not be relied upon!
%    \begin{macrocode}
local function strcmp(A, B)
  if A == B then
    write("0")
  elseif A < B then
    write("-1")
  else
    write("1")
  end
end
l3kernel.strcmp = strcmp
%    \end{macrocode}
% \end{macro}
%
% \subsection{Generic \Lua{} and font support}
%
%    \begin{macrocode}
%<*initex>
%    \end{macrocode}
%
% A small amount of generic code is used by almost all \LuaTeX{} material so
% needs to be loaded by the format.
%    \begin{macrocode}
attribute_count_name = "g__alloc_attribute_int"
bytecode_count_name  = "g__alloc_bytecode_int"
chunkname_count_name = "g__alloc_chunkname_int"
whatsit_count_name   = "g__alloc_whatsit_int"
require("ltluatex")
%    \end{macrocode}
%
% With the above available the font loader code used by plain \TeX{} and
% \LaTeXe{} when used with \LuaTeX{} can be loaded here. This is thus being
% treated more-or-less as part of the engine itself.
%    \begin{macrocode}
require("luaotfload-main")
local _void = luaotfload.main()
%    \end{macrocode}
%    \begin{macrocode}
%</initex>
%    \end{macrocode}
%
%    \begin{macrocode}
%</lua>
%    \end{macrocode}
%
%    \begin{macrocode}
%</initex|package>
%    \end{macrocode}
%
%\end{implementation}
%
%\PrintIndex
