%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% --------------------------------------------------------------------------- %
% - the CHEMMACROS bundle                                                   - %
% - ghsystem.sty                                                            - %
% - macros and commands for chemists                                        - %
% --------------------------------------------------------------------------- %
% - Clemens Niederberger                                                    - %
% --------------------------------------------------------------------------- %
% - https://bitbucket.org/cgnieder/chemmacros/                              - %
% - contact@mychemistry.eu                                                  - %
% --------------------------------------------------------------------------- %
% - If you have any ideas, questions, suggestions or bugs to report, please - %
% - feel free to contact me.                                                - %
% --------------------------------------------------------------------------- %
% - Copyright 2011-2013 Clemens Niederberger                                - %
% -                                                                         - %
% - This work may be distributed and/or modified under the                  - %
% - conditions of the LaTeX Project Public License, either version 1.3      - %
% - of this license or (at your option) any later version.                  - %
% - The latest version of this license is in                                - %
% -   http://www.latex-project.org/lppl.txt                                 - %
% - and version 1.3 or later is part of all distributions of LaTeX          - %
% - version 2005/12/01 or later.                                            - %
% -                                                                         - %
% - This work has the LPPL maintenance status `maintained'.                 - %
% -                                                                         - %
% - The Current Maintainer of this work is Clemens Niederberger.            - %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\RequirePackage{ expl3, xparse, l3keys2e }
\def\ghsystem@version{4.0a}
\def\ghsystem@date{2013/12/13}
\ProvidesExplPackage
  {ghsystem}
  {\ghsystem@date}
  {\ghsystem@version}
  {globally harmonised system}

% --------------------------------------------------------------------------
% check expl3 version:
\@ifpackagelater { expl3 } { 2012/11/21 }
  { }
  {
    \PackageError { ghsystem } { Support~package~expl3~too~old }
      {
        You~need~to~update~your~installation~of~the~bundles~'l3kernel'~and~
        'l3packages'.\MessageBreak
        Loading~ghsystem~will~abort!
      }
    \tex_endinput:D
  }

% --------------------------------------------------------------------------- %
% error and warning messages:
\msg_set:nnnn { ghsystem } { explicit }
  { It~seems~you've~loaded~`ghsystem'~explicitly. }
  {
    It~seems~you've~loaded~`ghsystem'~explicitly.~This~should~work~but~the~
    recommended~way~is~to~load~it~via~the~bundle,~i.e.~by~using~
    \token_to_str:N \usepackage \{ chemmacros \}.
  }
  
\msg_set:nnnn { ghsystem } { statements }
  {
    You've~tried~to~call~statement~#1#2~ \msg_line_context: \c_space_tl but~it~
    it~is~not~defined~in~ghsystem.sty .
  }
  {
    You've~tried~to~call~statement~#1#2~ \msg_line_context: \c_space_tl but~it~
    it~is~not~defined~in~ghsystem.sty . ~ Are~you~sure~it~exists? ~ If~so~please
    ~send~a~message~to~the~author.~Thanks.
  }

\msg_set:nnnn { ghsystem } { booktabs }
  { Package~`booktabs'~missing~\msg_line_context: . }
  {
    Option~#1~of~the~\token_to_str:N \ghslistall \c_space_tl command~
    \msg_line_context: \c_space_tl needs~the~`booktabs'~package . ~Please~make~
    sure~to~load~it~in~your~preamble.
  }

\cs_new_protected:Npn \ghsystem_msg:nnxx #1#2#3#4
  {
    \bool_if:NTF \l__ghsystem_strict_bool
      { \msg_error:nnxx { #1 } { #2 } { #3 } { #4 } }
      { \msg_warning:nnxx { #1 } { #2 } { #3 } { #4 } }
  }

% --------------------------------------------------------------------------
% package options:
\bool_new:N \l__ghsystem_strict_bool
\keys_define:nn { chemmacros / ghsystem }
  {
    strict   .bool_set:N = \l__ghsystem_strict_bool ,
    strict   .default:n  = true ,
    language .code:n     = \ghsystem_load_language:n { #1 }
  }

\AtBeginDocument
  {
    \@ifpackageloaded{ chemmacros }
      {
        \bool_if:NT \l_chemmacros_strict_bool
          { \bool_set_true:N \l__ghsystem_strict_bool }
      }
      {
        \cs_new:Npn \iupac #1
          {
            \group_begin:
              \cs_set_eq:NN \| \scan_stop:
              #1
            \group_end:
          }
      }
  }

% --------------------------------------------------------------------------- %
% variants of kernel functions:
\cs_generate_variant:Nn \file_if_exist:nTF { x }

% --------------------------------------------------------------------------- %
% scratch variables
\tl_new:N  \l__ghsystem_tmpa_tl
\tl_new:N  \l__ghsystem_tmpb_tl
\int_new:N \l__ghsystem_tmpa_int
\int_new:N \l__ghsystem_tmpb_int

% load required packages:
\RequirePackage{ translations , siunitx , graphicx , longtable , ifpdf }

% --------------------------------------------------------------------------- %
% define variables:
\prop_new:N \l__ghsystem_h_prop
\prop_new:N \l__ghsystem_euh_prop
\prop_new:N \l__ghsystem_p_prop

\cs_new:Npn \ghsystem_exposure: {}
\cs_new:Npn \ghsystem_effect: {}
\cs_new:Npn \ghsystem_organs: {}
\cs_new:Npn \ghsystem_substance: {}
\cs_new:Npn \ghsystem_text: {}
\cs_new:Npn \ghsystem_dash:
  {
    \tex_penalty:D \c_ten_thousand
    -
    \skip_horizontal:N \c_zero_skip
  }

\cs_new:Npn \ghsystem_slash:
  {
    \tex_penalty:D \c_ten_thousand
    /
    \skip_horizontal:N \c_zero_skip
  }

\bool_new:N \l__ghsystem_fill_in_bool
\bool_new:N \l__ghsystem_show_number_bool
\bool_new:N \l__ghsystem_substance_bool
\bool_new:N \l__ghsystem_organs_bool
\bool_new:N \l__ghsystem_hide_statement_bool
\bool_new:N \l__ghsystem_engine_pdftex_bool
\bool_new:N \l__ghsystem_engine_xetex_bool
\bool_new:N \l__ghsystem_engine_luatex_bool

\tl_new:N   \l__ghsystem_number_space_tl
\tl_new:N   \l__ghsystem_celsius_temperature_tl
\tl_new:N   \l__ghsystem_fahrenheit_temperature_tl
\tl_new:N   \l__ghsystem_kg_mass_tl
\tl_new:N   \l__ghsystem_lbs_mass_tl
\tl_new:N   \l__ghsystem_dots_tl
\tl_set:Nn  \l__ghsystem_dots_tl { \ldots }
\tl_new:N   \l__ghsystem_picture_scale_default_tl
\tl_set:Nn  \l__ghsystem_picture_scale_default_tl { .05 }
\tl_new:N   \l__ghsystem_picture_scale_tl
\tl_set_eq:NN \l__ghsystem_picture_scale_tl \l__ghsystem_picture_scale_default_tl
\tl_new:N   \l__ghsystem_picture_includegraphics_tl
\tl_new:N   \l__ghsystem_picture_type_tl
\tl_new:N   \l__ghsystem_identifier_tl
\tl_new:N   \l__ghsystem_table_text_tl
\tl_new:N   \l__ghsystem_table_next_page_tl
\tl_new:N   \l__ghsystem_table_head_rule_tl
\tl_set:Nn  \l__ghsystem_table_head_rule_tl { \hline }
\tl_new:N   \l__ghsystem_table_top_head_rule_tl
\tl_set:Nn  \l__ghsystem_table_top_head_rule_tl { \hline }
\tl_new:N   \l__ghsystem_table_foot_rule_tl
\tl_set:Nn  \l__ghsystem_table_foot_rule_tl { \hline }
\tl_new:N   \l__ghsystem_table_last_foot_rule_tl
\tl_set:Nn  \l__ghsystem_table_last_foot_rule_tl { \hline }
\tl_new:N   \l__ghsystem_table_caption_tl
\tl_new:N   \l__ghsystem_table_caption_short_tl
\tl_new:N   \l__ghsystem_table_label_tl
\tl_set:Nn  \l__ghsystem_table_label_tl { tab : ghs-hp-statements }
\tl_new:N   \l__ghsystem_list_all_column_format_tl

\dim_new:N  \l__ghsystem_list_all_column_width_dim
\dim_set:Nn \l__ghsystem_list_all_column_width_dim { .7\linewidth }
\dim_new:N  \l__ghsystem_table_line_sep_dim
\dim_set:Nn \l__ghsystem_table_line_sep_dim { 3pt }

\fp_new:N   \l__ghsystem_picture_scale_fp
\fp_set:Nn  \l__ghsystem_picture_scale_fp { \l__ghsystem_picture_scale_tl }

\DeclareSIUnit { \GHSfahrenheit } { \SIUnitSymbolDegree F }
\DeclareSIUnit { \GHScelsius } { \SIUnitSymbolDegree C }
\DeclareSIUnit { \GHSkilogram } { kg }
\DeclareSIUnit { \GHSpounds } { lbs }

% language settings
\bool_new:N \l__ghsystem_language_file_loaded_bool
\bool_new:N \l__ghsystem_language_directory_bool

% load the language file -- it needs expl3 namespace but shouldn't care about
% what catcode regime was before and simply restore it

\cs_new:Npn \__ghsystem_namespace_restore: {}

\cs_new_protected:Npn \__ghsystem_expl_namespace:
  {
    \group_begin:
      \cs_gset_protected:Npx \__ghsystem_namespace_restore:
        {
          \char_set_catcode:nn { 9 } { \char_value_catcode:n { 9 } }
          \char_set_catcode:nn { 32 } { \char_value_catcode:n { 32 } }
          \char_set_catcode:nn { 34 } { \char_value_catcode:n { 34 } }
          \char_set_catcode:nn { 38 } { \char_value_catcode:n { 38 } }
          \char_set_catcode:nn { 58 } { \char_value_catcode:n { 58 } }
          \char_set_catcode:nn { 94 } { \char_value_catcode:n { 94 } }
          \char_set_catcode:nn { 95 } { \char_value_catcode:n { 95 } }
          \char_set_catcode:nn { 124 } { \char_value_catcode:n { 124 } }
          \char_set_catcode:nn { 126 } { \char_value_catcode:n { 126 } }
          \tex_endlinechar:D = \tex_the:D \tex_endlinechar:D \scan_stop:
        }
    \group_end:
    \ExplSyntaxOn
  }

\cs_new:Npn \ghsystem_load_language_file:n #1
  {
    \__ghsystem_expl_namespace:
    \input ghsystem_#1.def \scan_stop:
    \__ghsystem_namespace_restore:
  }

\cs_new_protected:Npn \ghsystem_load_language:n #1
  {
    \file_if_exist:xTF { ghsystem_ #1 .def }
      {
        \bool_set_true:N \l__ghsystem_language_file_loaded_bool
        \ghsystem_load_language_file:n { #1 }
      }
      { \ghsystem_load_language_file:n { english } }
  }
\cs_generate_variant:Nn \ghsystem_load_language:n { V }

\NewDocumentCommand \loadghsystemlanguage { m }
  { \ghsystem_load_language:n { #1 } }

\AtBeginDocument{
  \bool_if:NF \l__ghsystem_language_file_loaded_bool
    {
      \cs_if_exist:NTF \l_chemmacros_language_tl
        { \ghsystem_load_language:V \l_chemmacros_language_tl }
        {
          \ghsystem_load_language:n
            { \@trnslt@language{\@trnslt@current@language} }
        }
    }
}

\cs_new_nopar:Nn \ghsystem_booktabs:n
  {
    \cs_if_exist:cF { ver@booktabs.sty }
      { \msg_error:nnx { ghsystem } { booktabs } { #1 } }
  }

% --------------------------------------------------------------------------- %
% define options:
\keys_define:nn { chemmacros / ghsystem }
  {
    % \ghs options:
    hide                            .bool_set:N =
      \l__ghsystem_hide_statement_bool ,
    hide                            .default:n  = true ,
    fill-in                         .bool_set:N = \l__ghsystem_fill_in_bool ,
    fill-in                         .default:n  = true ,
    exposure                        .code:n     =
      \cs_set:Npn \ghsystem_exposure: { ~ #1 } ,
    effect                          .code:n     =
      \cs_set:Npn \ghsystem_effect: { ~ #1 } ,
    organs                          .code:n     =
      \bool_set_true:N \l__ghsystem_organs_bool
      \cs_set:Npn \ghsystem_organs: { ~ #1 } ,
    substance                       .code:n     =
      \bool_set_true:N \l__ghsystem_substance_bool
      \cs_set:Npn \ghsystem_substance: { ~ #1 } ,
    text                            .code:n     =
      \cs_set:Npn \ghsystem_text: { ~ #1 } ,
    space                           .tl_set:N   =
      \l__ghsystem_number_space_tl ,
    C-temperature                   .tl_set:N   =
      \l__ghsystem_celsius_temperature_tl ,
    F-temperature                   .tl_set:N   =
      \l__ghsystem_fahrenheit_temperature_tl ,
    kg-mass                         .tl_set:N   = \l__ghsystem_kg_mass_tl ,
    lbs-mass                        .tl_set:N   = \l__ghsystem_lbs_mass_tl ,
    dots                            .tl_set:N   = \l__ghsystem_dots_tl ,
    % \ghspic options:
    scale                           .code:n     =
      \fp_mul:Nn \l__ghsystem_picture_scale_fp { #1 } ,
    includegraphics                 .code:n     =
      \tl_set:Nn \l__ghsystem_picture_includegraphics_tl { , #1 } ,
    pic-type                        .choices:nn = { eps , jpg , png , pdf }
      { \tl_set_eq:NN \l__ghsystem_picture_type_tl \l_keys_choice_tl } ,
    % \ghslistall options:
    table-head-number               .tl_set:N   = \l__ghsystem_identifier_tl ,
    table-head-text                 .tl_set:N   = \l__ghsystem_table_text_tl ,
    table-next-page                 .tl_set:N   =
      \l__ghsystem_table_next_page_tl ,
    table-row-sep                   .dim_set:N  =
      \l__ghsystem_table_line_sep_dim ,
    table-head-rule                 .choice: ,
    table-head-rule / default       .code:n     =
      \tl_set:Nn \l__ghsystem_table_head_rule_tl { \hline } ,
    table-head-rule / booktabs      .code:n     =
      \ghsystem_booktabs:n { table-head-rule }
      \tl_set:Nn \l__ghsystem_table_head_rule_tl { \midrule } ,
    table-head-rule / none          .code:n     =
      \tl_clear:N \l__ghsystem_table_head_rule_tl ,
    table-top-head-rule             .choice: ,
    table-top-head-rule / default   .code:n     =
      \tl_set:Nn \l__ghsystem_table_top_head_rule_tl { \hline } ,
    table-top-head-rule / booktabs  .code:n     =
      \ghsystem_booktabs:n { table-top-head-rule }
      \tl_set:Nn \l__ghsystem_table_top_head_rule_tl { \toprule } ,
    table-top-head-rule / none      .code:n     =
      \tl_clear:N \l__ghsystem_table_top_head_rule_tl ,
    table-foot-rule                 .choice: ,
    table-foot-rule / default       .code:n     =
      \tl_set:Nn \l__ghsystem_table_foot_rule_tl { \hline } ,
    table-foot-rule / booktabs      .code:n     =
      \ghsystem_booktabs:n { table-foot-rule }
      \tl_set:Nn \l__ghsystem_table_foot_rule_tl { \midrule } ,
    table-foot-rule / none          .code:n     =
      \tl_clear:N \l__ghsystem_table_foot_rule_tl ,
    table-last-foot-rule            .choice: ,
    table-last-foot-rule / default  .code:n     =
      \tl_set:Nn \l__ghsystem_table_last_foot_rule_tl { \hline } ,
    table-last-foot-rule / booktabs .code:n     =
      \ghsystem_booktabs:n { table-last-foot-rule }
      \tl_set:Nn \l__ghsystem_table_last_foot_rule_tl { \bottomrule } ,
    table-last-foot-rule / none     .code:n     =
      \tl_clear:N \l__ghsystem_table_last_foot_rule_tl ,
    table-rules                     .choice: ,
    table-rules / default           .code:n     =
      \tl_set:Nn \l__ghsystem_table_head_rule_tl { \hline }
      \tl_set:Nn \l__ghsystem_table_top_head_rule_tl { \hline }
      \tl_set:Nn \l__ghsystem_table_foot_rule_tl { \hline }
      \tl_set:Nn \l__ghsystem_table_last_foot_rule_tl { \hline } ,
    table-rules / booktabs          .code:n     =
      \ghsystem_booktabs:n { table-rules }
      \tl_set:Nn \l__ghsystem_table_head_rule_tl { \midrule }
      \tl_set:Nn \l__ghsystem_table_top_head_rule_tl { \toprule }
      \tl_set:Nn \l__ghsystem_table_foot_rule_tl { \midrule }
      \tl_set:Nn \l__ghsystem_table_last_foot_rule_tl { \bottomrule } ,
    table-rules / none              .code:n     =
      \tl_clear:N \l__ghsystem_table_head_rule_tl
      \tl_clear:N \l__ghsystem_table_top_head_rule_tl
      \tl_clear:N \l__ghsystem_table_foot_rule_tl
      \tl_clear:N \l__ghsystem_table_last_foot_rule_tl ,
    table-caption                   .tl_set:N   =
      \l__ghsystem_table_caption_tl ,
    table-caption-short             .tl_set:N   =
      \l__ghsystem_table_caption_short_tl ,
    table-label                     .tl_set:N   =
      \l__ghsystem_table_label_tl ,
    table-column-format             .tl_set:N   =
      \l__ghsystem_list_all_column_format_tl ,
    table-column-width              .dim_set:N  =
      \l__ghsystem_list_all_column_width_dim
  }

% --------------------------------------------------------------------------- %
% the main command for getting the H/EUH/P statements
%   \ghs{<type>}{<num>}
%   \ghs*{<type>}{<num>} : type without number
%
\NewDocumentCommand \ghs { somm }
  {
    \group_begin:
      \IfBooleanF { #1 } { \bool_set_true:N \l__ghsystem_show_number_bool }
      \IfNoValueF { #2 } { \keys_set:nn { chemmacros / ghsystem } { #2 } }
      \ghsystem_read_args:nn { #3 } { #4 }
    \group_end:
  }

\cs_new:Nn \ghsystem_read_args:nn
  {
    \__ghsystem_get_type:nN { #1 } \l__ghsystem_tmpa_tl
    \prop_get:cnNTF { l__ghsystem_ \l__ghsystem_tmpa_tl _prop } { #2 } \l__ghsystem_tmpb_tl
      {
        \__ghsystem_is_combination:nn { #1 } { #2 }
        \bool_if:NF \l__ghsystem_hide_statement_bool
          { \tl_use:N \l__ghsystem_tmpb_tl  }
      }
      { \ghsystem_msg:nnxx { ghsystem } { statements } { #1 } { #2 } }
  }

\cs_new_protected:Nn \__ghsystem_get_type:nN
  {
    \tl_if_eq:nnT { #1 } { h }   { \tl_set:Nn #2 { h } }
    \tl_if_eq:nnT { #1 } { H }   { \tl_set:Nn #2 { h } }
    \tl_if_eq:nnT { #1 } { euh } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { Euh } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { euH } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { eUh } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { EUh } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { EuH } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { eUH } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { EUH } { \tl_set:Nn #2 { euh } }
    \tl_if_eq:nnT { #1 } { p }   { \tl_set:Nn #2 { p } }
    \tl_if_eq:nnT { #1 } { P }   { \tl_set:Nn #2 { p } }
  }

\cs_new:Nn \__ghsystem_is_combination:nn
  {
    \tl_if_in:nnTF { #2 } { + }
      { \__ghsystem_is_combination_aux_i:w #1,#2 \q_stop }
      { \__ghsystem_is_combination_aux_ii:w #1,#2 \q_stop }
  }

\cs_new:Npn \__ghsystem_is_combination_aux_i:w #1,#2+#3 \q_stop
  {
    \bool_if:NT \l__ghsystem_show_number_bool
      {
        \tl_to_uppercase:n { #1 }
        \tl_use:N \l__ghsystem_number_space_tl
        #2 ~ + ~
        \tl_if_in:nnTF { #3 } { + }
          { \__ghsystem_is_combination_aux_iii:w #1,#3 \q_stop }
          {
            \tl_to_uppercase:n { #1 }
            \tl_use:N \l__ghsystem_number_space_tl
            #3 \bool_if:NF \l__ghsystem_hide_statement_bool { : ~ }
          }
      }
  }

\cs_new:Npn \__ghsystem_is_combination_aux_ii:w #1,#2 \q_stop
  {
    \bool_if:NT \l__ghsystem_show_number_bool
      {
        \tl_to_uppercase:n { #1 }
        \tl_use:N \l__ghsystem_number_space_tl
        #2 \bool_if:NF \l__ghsystem_hide_statement_bool { : ~ }
      }
  }

\cs_new:Npn \__ghsystem_is_combination_aux_iii:w #1,#2+#3 \q_stop
  {
    \bool_if:NT \l__ghsystem_show_number_bool
      {
        \tl_to_uppercase:n { #1 }
        \tl_use:N \l__ghsystem_number_space_tl
        #2 ~ + ~
        \tl_to_uppercase:n { #1 }
        \tl_use:N \l__ghsystem_number_space_tl
        #3 \bool_if:NF \l__ghsystem_hide_statement_bool { : ~ }
      }
  }

% --------------------------------------------------------------------------- %
% list all statements in a table
%
\NewDocumentCommand \ghslistall { o }
  {
    \group_begin:
      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / ghsystem } { #1 } }
      \ghsystem_list_all:
    \group_end:
  }

\cs_new_protected:Npn \ghsystem_list_all:
  {
    \int_zero:N \l__ghsystem_tmpa_int
    \int_zero:N \l__ghsystem_tmpb_int
    \prop_map_inline:Nn \l__ghsystem_p_prop { \int_incr:N \l__ghsystem_tmpa_int }
    \dim_set_eq:NN \extrarowheight \l__ghsystem_table_line_sep_dim
    \begin { longtable }
      {
        l
        >{ \l__ghsystem_list_all_column_format_tl }
        p{ \l__ghsystem_list_all_column_width_dim }
      }
        \caption [ \l__ghsystem_table_caption_short_tl ]
          {
            \l__ghsystem_table_caption_tl
            \exp_args:No \label { \l__ghsystem_table_label_tl }
          } \\
        \l__ghsystem_table_top_head_rule_tl
        \textbf { \l__ghsystem_identifier_tl } &
        \textbf { \l__ghsystem_table_text_tl } \\
        \l__ghsystem_table_head_rule_tl
      \endfirsthead
        \l__ghsystem_table_top_head_rule_tl
        \textbf { \l__ghsystem_identifier_tl } &
        \textbf { \l__ghsystem_table_text_tl } \\
        \l__ghsystem_table_head_rule_tl
      \endhead
        \l__ghsystem_table_last_foot_rule_tl
        \multicolumn{2}{r} { \textit { \l__ghsystem_table_next_page_tl } }
      \endfoot
        \l__ghsystem_table_foot_rule_tl \multicolumn{2}{r} { }
      \endlastfoot
      \prop_map_inline:Nn \l__ghsystem_h_prop
        { \__ghsystem_read_number:nn { H } { ##1 } & ##2 \\ }
      \prop_map_inline:Nn \l__ghsystem_euh_prop
        { \__ghsystem_read_number:nn { EUH } { ##1 } & ##2 \\ }
      \int_zero:N \l__ghsystem_tmpa_int
      \prop_map_inline:Nn \l__ghsystem_p_prop { \int_gincr:N \l__ghsystem_tmpa_int }
      \int_zero:N \l__ghsystem_tmpb_int
      \prop_map_inline:Nn \l__ghsystem_p_prop
        {
          \int_gincr:N \l__ghsystem_tmpb_int
          \__ghsystem_read_number:nn { P } { ##1 } & ##2
          \int_compare:nNnT { \l__ghsystem_tmpb_int } < { \l__ghsystem_tmpa_int } { \\ }
        }
    \end { longtable }
  }

\cs_new:Nn \__ghsystem_read_number:nn
  {
    \tl_if_in:nnTF { #2 } { + }
      { \__ghsystem_read_number_aux_i:w #1 , #2 \q_stop }
      { #1 \tl_use:N \l__ghsystem_number_space_tl #2 }
  }

\cs_new:Npn \__ghsystem_read_number_aux_i:w #1,#2+#3\q_stop
  {
     #1 \tl_use:N \l__ghsystem_number_space_tl #2 ~+~
     \tl_if_in:nnTF { #3 } { + }
       { \__ghsystem_read_number_aux_ii:w #1,#3 \q_stop }
       { #1#3 }
  }

\cs_new:Npn \__ghsystem_read_number_aux_ii:w #1,#2+#3\q_stop
  { #1#2 ~+~ #1#3 }

% --------------------------------------------------------------------------- %
% the picture command
%   \ghspic[<options>]{<name>}
%
% test for compilation engine/mode:
\pdftex_if_engine:T { \bool_set_true:N \l__ghsystem_engine_pdftex_bool }
\xetex_if_engine:T  { \bool_set_true:N \l__ghsystem_engine_xetex_bool }
\luatex_if_engine:T { \bool_set_true:N \l__ghsystem_engine_luatex_bool }

\bool_new:N \l__ghsystem_picture_directory_bool

\bool_if:NT \l__ghsystem_engine_pdftex_bool
  {
    \ifpdf
      \tl_set:Nn \l__ghsystem_picture_type_tl { pdf }
    \else
      \tl_set:Nn \l__ghsystem_picture_type_tl { eps }
    \fi
  }
\bool_if:NT \l__ghsystem_engine_xetex_bool
  { \tl_set:Nn \l__ghsystem_picture_type_tl { pdf } }
\bool_if:NT \l__ghsystem_engine_luatex_bool
  { \tl_set:Nn \l__ghsystem_picture_type_tl { pdf } }

% the command:
\NewDocumentCommand \ghspic { om }
  {
    \group_begin:
      \IfNoValueF { #1 } { \keys_set:nn { chemmacros / ghsystem } { #1 } }
      \ghsystem_pic:n { #2 }
    \group_end:
  }

\cs_new_protected:Npn \ghsystem_pic:n #1
  {
    \__ghsystem_includegraphics:xn
      {
        scale = \fp_to_tl:N \l__ghsystem_picture_scale_fp
        \exp_not:V \l__ghsystem_picture_includegraphics_tl
      }
      { ghsystem_ #1 . \l__ghsystem_picture_type_tl }
  }

\cs_new:Nn \__ghsystem_includegraphics:nn
  { \includegraphics[#1]{#2} }
\cs_generate_variant:Nn \__ghsystem_includegraphics:nn { xn }

% --------------------------------------------------------------------------
% options and setup
\ProcessKeysOptions{ chemmacros / ghsystem }

\cs_new_protected:Npn \ghsystem_setup:n #1
  { \keys_set:nn { chemmacros / ghsystem } { #1 } }

\NewDocumentCommand \ghssetup { m }
  { \ghsystem_setup:n { #1 } }

\tex_endinput:D
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
VERSION HISTORY
2012/01/30 - version 3.0a - renamed ghs => ghsystem to make the names unique
                            (following a request by Karl Berry for TeXlive)
2012/02/05 - version 3.0c - renamed pictogram files (following a request by
                            Karl Berry for TeXlive)
2012/05/13 - version 3.3a - Italian translations of the H, EUH and P statements
2012/05/18 - version 3.3b - compatibility with MiKTeX
2012/05/18 - version 3.3c - fix in the `ghsystem/language' option
2012/07/24 - version 3.3d - additional picture file type `pdf'
2013/02/19 - version 3.5a - bug fix: `ghsystem' recognizes language again
2013/07/06 - version 4.0  - dropped requirement of `tabu' package.
                          - new options `table-column-width' and
                            `table-column-format'
                          - adapted to changed language setting mechanism in
                            `chemmacros'
                          - new command: \loadghsystemlanguage
                          - the package can be used independently from
                            `chemmacros'
2013/12/13 - version 4.0a - small changes to `ghsystem_german.def'
                          - added \ghsystem_dash: and \ghsystem_slash:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% TODO:
- add option to switch between `longtable` and `supertabular` for \ghslistall ?