% --------------------------------------------------------------------------
% the LEADSHEETS package
% 
%   typesetting leadsheets and songbooks
%
% --------------------------------------------------------------------------
% Clemens Niederberger
% E-Mail: contact@mychemistry.eu
% --------------------------------------------------------------------------
% Copyright 2014-2017 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.
% --------------------------------------------------------------------------
% required packages:
\RequirePackage{expl3,l3keys2e,xparse,translations}

% --------------------------------------------------------------------------
% package information:
\ExplSyntaxOn
\tl_const:Nn \leadsheetsdate    {2017/09/26}
\tl_const:Nn \leadsheetsversion {0.5b}
\tl_const:Nn \leadsheetsinfo    {Typesetting leadsheets and songbooks}

\ProvidesExplPackage
  {leadsheets}
  {\leadsheetsdate}
  {\leadsheetsversion}
  {\leadsheetsinfo \c_space_tl (CN)}

% --------------------------------------------------------------------------
% messages:
\msg_new:nnn {leadsheets} {library-missing}
  {
    You've~ requested~ the~ leadsheets~ library~ `#1'~ but~ it~ appears~ to~
    be~ missing~ on~ your~ system.~ Maybe~ you've~ misspelled~ the~ name?~
    Loading~ the~ library~ will~ abort~ \msg_line_context:
  }

\msg_new:nnn {leadsheets} {loading-library}
  {
    (leadsheets) \c_space_tl \c_space_tl \c_space_tl \c_space_tl
    Loading~ library~ `#1'...
  }

% --------------------------------------------------------------------------
% variants of kernel functions:
\cs_generate_variant:Nn \tl_if_eq:nnTF       { xx , V }
\cs_generate_variant:Nn \seq_set_split:Nnn   { Nnx }
\cs_generate_variant:Nn \prop_item:Nn        { NV }
\cs_generate_variant:Nn \seq_item:Nn         { cV }
\cs_generate_variant:Nn \int_to_arabic:n     { V }
\cs_generate_variant:Nn \tl_replace_once:Nnn { NnV }
\cs_generate_variant:Nn \prop_gput:Nnn       { cxx , NVf }
\cs_generate_variant:Nn \msg_error:nnn       { nnV }
\cs_generate_variant:Nn \msg_warning:nnn     { nnV }
\cs_generate_variant:Nn \vbox_set:Nn         { NV }

% --------------------------------------------------------------------------
% temporary variables:
\tl_new:N   \l__leadsheets_tmpa_tl
\tl_new:N   \l__leadsheets_tmpb_tl
\tl_new:N   \l__leadsheets_tmpc_tl
\tl_new:N   \l__leadsheets_tmpd_tl
\tl_new:N   \g__leadsheets_tmpa_tl

\bool_new:N \l__leadsheets_tmpa_bool

\dim_new:N  \l__leadsheets_tmpa_dim

\seq_new:N  \l__leadsheets_tmpa_seq
\seq_new:N  \l__leadsheets_tmpb_seq

\int_new:N  \l__leadsheets_tmpa_int
\int_new:N  \l__leadsheets_tmpb_int
\int_new:N  \l__leadsheets_tmpc_int

\box_new:N  \l__leadsheets_tmpa_box

% --------------------------------------------------------------------------
\prg_new_conditional:Npnn \leadsheets_if_package_loaded:n #1 {p,T,F,TF}
  {
    \cs_if_exist:cTF {ver@#1.sty}
      { \prg_return_true: }
      { \prg_return_false: }
  }

\DeclareExpandableDocumentCommand \leadsheetsifpackageloaded {m}
  { \leadsheets_if_package_loaded:nTF {#1} }

% % --------------------------------------------------------------------------
% \seq_new:N \l__leadsheets_safed_commands_seq

% \cs_new_protected:Npn \leadsheets_safe_define_protected:Npn #1
%   {
%     \seq_if_in:NnTF \l__leadsheets_safed_commands_seq {#1}
%       {} % error
%       {
%         \seq_gput_right:Nn \l__leadsheets_safed_commands_seq {#1}
%         \cs_gset_eq:cN {__leadsheets_ \cs_to_str:N #1:} #1
%         \cs_set_protected:Npn #1
%       }
%   }

% \cs_new_protected:Npn \leadsheets_restore:N #1
%   {
%     \seq_if_in:NnTF \l__leadsheets_safed_commands_seq {#1}
%       { \cs_set_eq:Nc #1 {__leadsheets_ \cs_to_str:N #1:} }
%       {} % error
%     \seq_gremove_all:Nn \l__leadsheets_safed_commands_seq {#1}
%   }
  
% --------------------------------------------------------------------------
% library mechanism:
\tl_const:Nn \c__leadsheets_library_extension_tl {code.tex}
\tl_const:Nn \c__leadsheets_library_prefix_tl    {leadsheets.library}

\cs_new_protected:Npn \leadsheets_load_libraries:n #1
  { \clist_map_inline:nn {#1} { \leadsheets_load_library:n {##1} } }

\cs_new_protected:Npn \leadsheets_load_library:n #1
  {
    \tl_set:Nx \l__leadsheets_tmpa_tl { \tl_trim_spaces:n {#1} }
    \__leadsheets_load_library:V \l__leadsheets_tmpa_tl
  }

\prg_new_conditional:Npnn \leadsheets_if_library:n #1 {p,T,F,TF}
  {
    \cs_if_exist:cTF {leadsheets-library-#1-loaded}
      { \prg_return_true: }
      { \prg_return_false: }
  }

\DeclareExpandableDocumentCommand \leadsheetsiflibrary {m}
  { \leadsheets_if_library:nTF {#1} }
  
\cs_new_protected:Npn \__leadsheets_load_library:n #1
  {
    \leadsheets_if_library:nF {#1}
      {
        \file_if_exist:nTF
          {\c__leadsheets_library_prefix_tl.#1.\c__leadsheets_library_extension_tl}
          {
            \msg_log:nnn {leadsheets} {loading-library} {#1}
            \@onefilewithoptions
              {\c__leadsheets_library_prefix_tl.#1}[][]
              \c__leadsheets_library_extension_tl
          }
          { \msg_warning:nnn {leadsheets} {library-missing} {#1} }
      }
  }
\cs_generate_variant:Nn \__leadsheets_load_library:n { V }

\cs_new_protected:Npn \__leadsheets_library:nn #1#2
  {
    \cs_new:cpn {leadsheets-library-#1-loaded} {leadsheets:~`#1'~library}
    \ProvidesFile
      {\c__leadsheets_library_prefix_tl.#1.\c__leadsheets_library_extension_tl}
      [
        \leadsheetsdate
        \c_space_tl
        v \leadsheetsversion
        \c_space_tl
        leadsheets~ library~ `#1'~ #2
      ]
  }

% 
\cs_new:Npn \LeadsheetSurvive #1 \LeadsheetEndSurvive {#1}

% --------------------------------------------------------------------------
% one of those defines a leadsheets library, either using expl syntax or 2e
% package syntax:
\NewDocumentCommand \LeadsheetsExplLibrary {mm}
  { \__leadsheets_library:nn {#1} {#2} \ExplSyntaxOn }

\NewDocumentCommand \LeadsheetsLibrary {mm}
  { \__leadsheets_library:nn {#1} {#2} }

% --------------------------------------------------------------------------
% commands for loading libraries:
\NewDocumentCommand \useleadsheetslibraries {m}
  { \leadsheets_load_libraries:n {#1} }

\NewDocumentCommand \useleadsheetslibrary {m}
  { \leadsheets_load_library:n {#1} }

% --------------------------------------------------------------------------
% a setup command:
\NewDocumentCommand \setleadsheets {m}
  { \keys_set:nn {leadsheets} {#1} }

% --------------------------------------------------------------------------
% package options:
\bool_new:N \l__leadsheets_with_options_bool

\keys_define:nn {leadsheets}
  {
    musicsymbols .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool
      \leadsheets_load_library:n {musicsymbols} ,
    chords       .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool
      \leadsheets_load_library:n {chords} ,
    musejazz     .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool
      \leadsheets_load_library:n {musejazz} ,
    songs        .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool
      \leadsheets_load_library:n {songs} ,
    external     .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool
      \leadsheets_load_library:n {external} ,
    minimal      .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool ,
    full         .code:n =
      \bool_set_true:N \l__leadsheets_with_options_bool
      \leadsheets_load_libraries:n
        {
          musicsymbols ,
          chordnames ,
          songs ,
          chords ,
          shorthands ,
          properties ,
          transposing ,
          templates ,
          translations ,
          external
        }
  }
\ProcessKeysOptions{leadsheets}

\bool_if:NF \l__leadsheets_with_options_bool
  { \leadsheets_load_library:n {songs} }
  
% --------------------------------------------------------------------------
\file_input_stop:

2016/08/18 - new commands: \leadsheetsifpackageloaded, \leadsheetsiflibrary
           - new class `leadsheet'
           - new library `external'
           - minor chords can now be typeset with lowercase letters
             (chordnames)

