%%
%% This is file `cascade.sty',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% cascade.dtx  (with options: `package')
%% 
%% Copyright (C) 2018 by F. Pantigny
%% 
%% This file 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.
%% 
\def\myfileversion{1.01}
\def\myfiledate{2018/07/12}
\RequirePackage{l3keys2e}
\ProvidesExplPackage
  {cascade}
  {\myfiledate}
  {\myfileversion}
  {Easy presentation of demonstrations in cascades}
\RequirePackage{xparse}
%%
%% The following macro is the same as the macro of amsmath
\cs_if_free:NT \spread@equation
    {\cs_set_protected:Npn \spread@equation
               {\openup\jot
                \cs_set_protected:Npn \spread@equation {}}}
%%
%% The following registers will be used for the options.
\dim_new:N \l__cascade_interline_dim
\dim_new:N \l__cascade_interline_all_dim
\dim_new:N \l__cascade_space_between_dim
\dim_set:Nn \l__cascade_space_between_dim {0.5 em}
%%
%% This set of options will be used by \Cascade and \ShortCascade
\keys_define:nn {cascade/command}
  {
   interline          .dim_set:N        = \l__cascade_interline_dim,
   interline          .value_required:n = true ,
   interline-all      .code:n           = { \dim_set:Nn \l__cascade_interline_all_dim {#1}
                                            \dim_set:Nn \l__cascade_interline_dim {#1} },
   interline-all      .value_required:n = true,
   space-between      .dim_set:N        = \l__cascade_space_between_dim,
   space-between      .value_required:n = true}
%%
%% This set of options will be used by \CascadeOptions
\keys_define:nn {cascade/global}
  {interline-all      .dim_set:N        = \l__cascade_interline_all_dim,
   interline-all      .value_required:n = true,
   space-between      .dim_set:N        = \l__cascade_space_between_dim,
   space-between      .value_required:n = true}
\NewDocumentCommand \CascadeOptions {m}
    {\keys_set:nn {cascade/global} {#1}}
%%
%% The command \Cascade is defined with \NewDocumentCommand of xparse
\NewDocumentCommand \Cascade {O{} mmmm}
   { \if_mode_math:
        \msg_error:nn {cascade} {Cascade~in~math~mode}
     \fi:
     \mode_leave_vertical:
     \group_begin:
     \spread@equation
     \dim_set_eq:NN \l__cascade_interline_dim \l__cascade_interline_all_dim
     \keys_set:nn {cascade/command} {#1}
     \box_clear_new:N \l__cascade_box_one
     \box_clear_new:N \l__cascade_box_two
     \box_clear_new:N \l__cascade_box_three
     \box_clear_new:N \l__cascade_box_four
     \hbox_set:Nn \l__cascade_box_one {#2}
     \hbox_set:Nn \l__cascade_box_two {#3}
     \hbox_set:Nn \l__cascade_box_three {#4}
     \hbox_set:Nn \l__cascade_box_four {#5}
     \dim_zero_new:N \l__cascade_top_dim
     \dim_set:Nn \l__cascade_top_dim
            {\dim_max:nn \c_zero_dim
                         {\box_ht:N \l__cascade_box_one - \box_ht:N \l__cascade_box_two}}
     \dim_zero_new:N \l__cascade_bottom_dim
     \dim_set:Nn \l__cascade_bottom_dim
            {\dim_max:nn \c_zero_dim
                         {\box_dp:N \l__cascade_box_three - \box_dp:N \l__cascade_box_four}}
     \box_set_ht:Nn \l__cascade_box_one \c_zero_dim
     \box_set_dp:Nn \l__cascade_box_three \c_zero_dim
     \vbox:n
      {\skip_vertical:N \l__cascade_top_dim
       \vbox_top:n
        {\hbox:n
          {$\left.
              \vcenter {\halign{\hfil##\cr
                                \hbox:n{\tl_if_empty:nF {#2}
                                          {\box_use_drop:N \l__cascade_box_one
                                           \skip_horizontal:n \l__cascade_space_between_dim}
                                        \box_use_drop:N \l__cascade_box_two \strut} \cr
                                \noalign{\skip_vertical:n \l__cascade_interline_dim}
                                \hbox:n{\tl_if_empty:nF {#4}
                                          {\box_use_drop:N \l__cascade_box_three
                                           \skip_horizontal:n \l__cascade_space_between_dim}
                                        \box_use_drop:N \l__cascade_box_four \strut} \cr
                               }
                       }
            \right\}$
          }
         \skip_vertical:N \l__cascade_bottom_dim
        }
      }
     \group_end:
}
\msg_new:nnn {cascade}
             {Cascade~in~math~mode}
             {The~commands~\token_to_str:N \Cascade\
              and~\token_to_str:N \ShortCascade\
              should~be~used~in~text~mode~only.~However,~you~can~
              go~on~for~this~time.}
\NewDocumentCommand \ShortCascade {O{}mm}
    {\Cascade[#1]{}{#2}{}{#3}}

\endinput
%%
%% End of file `cascade.sty'.
