refactor: remove the use of mark for sectioning

use variable directly

source/pretfg.dtx

@@ -120,34 +120,35 @@
 %
 % \begin{implementation}
 %
+% NOTE: For the implementation of foreground/sectioning, use variable of \LaTeX3
+%       directly instead of the traditional mark, since the traditional mark
+%       only gets updated when the page is created. Sometimes a higher level of
+%       sectioning gets inserted and no intermediate information until the next
+%       sectioning level, and the information could be swallowed since it only
+%       compares the information from the previous page state, which is not 
+%       beneficial for the new \presenter{} mechanism running.
+%
 % \pkg{default} style.
-% foreground/headline is implemented using the basic \tn{rightmark}.
-% foreground/sectioning just uses \tn{markright} for basic general availablity.
 %    \begin{macrocode}
 %<*default>
 %<@@=pretfg_default>
+\tl_new:N \l_@@_fg_headline_title_tl
 \tl_new:N \l_@@_fg_headline_style_tl
 \DeclareTemplateCode { foreground / headline } { default } { 0 }
   { style = \l_@@_fg_headline_style_tl }
   {
     \AssignTemplateKeys
     \group_begin:  
       \l_@@_fg_headline_style_tl
-      \rightmark
+      \tl_use:N \l_@@_fg_headline_title_tl
     \group_end:
     \hfil
   }
-%    \end{macrocode}
-% \pkg{default} style of foreground/sectioning just uses \tn{markright}.
-%    \begin{macrocode}
 \DeclareTemplateCode { foreground / sectioning } { default } { 2 }
   { }
   {
-    \markright { #2 }
+    \tl_set:Nn \l_@@_fg_headline_title_tl { #2 }
   }
-%    \end{macrocode}
-% foreground/footline will print the page number.
-%    \begin{macrocode}
 \tl_new:N \l_@@_fg_footline_style_tl
 \DeclareTemplateCode { foreground / footline } { default } { 0 }
   { style = \l_@@_fg_footline_style_tl }
@@ -178,8 +179,6 @@
 %   \l_@@_fg_headline_cur_sec_lv_int
 % }
 % Store the previous or the current section level.
-% Here an int variable is used instead of a mark, since the mark grabbed by
-% \cs{LastMark} is not expandable and cannot be processed by \cs{int_eval:n}.
 %    \begin{macrocode}
 \int_new:N \l_@@_fg_headline_prev_sec_lv_int
 \int_set_eq:NN \l_@@_fg_headline_prev_sec_lv_int
@@ -202,23 +201,10 @@
 \box_new:N \l_@@_fg_headline_parent_box
 %    \end{macrocode}
 % \end{variable}
-% 
-% Here, \presenter{} uses the new mark mechanism instead of legacy \tn{leftmark}
-% and \tn{rightmark} for the following reasons:
-% \begin{itemize}
-%  \item \LaTeX3 now encourages to use the new interface and the source code of
-%        the \LaTeX{} format \file{ltmarks.dtx} has already swapped the original
-%        implementation of those commands to the new version.
-%  \item The current implementation needs to take care of three marks instead of
-%        only two marks.
-%  \item Maybe the star mark is not necessary, since the design could be changed
-%        in the future. But using the new interface will make the comparsion of
-%        marks easier.
-% \end{itemize}
 %    \begin{macrocode}
-\NewMarkClass { pretprevmark }
-\NewMarkClass { pretcurmark }
-\NewMarkClass { pretstarmark }
+\tl_new:N \l_@@_fg_headline_prev_title_tl
+\tl_new:N \l_@@_fg_headline_cur_title_tl
+\tl_new:N \l_@@_fg_headline_star_title_tl
 %    \end{macrocode}
 % It seems to be in horizontal mode in the header, use a \cs{vbox} to create a
 % vertical mode environment in order to adjust the vertical position of the
@@ -242,26 +228,32 @@
     \group_begin:
     \bool_if:NTF \l_@@_fg_headline_star_mark_bool
       {
-        \l_@@_fg_headline_child_style_tl 
-        \LastMark { pretstarmark }
+        \l_@@_fg_headline_child_style_tl
+        \tl_use:N \l_@@_fg_headline_star_title_tl
       }
       {
-        \mark_if_eq:nnnnnnTF { page } { pretprevmark } { last }
-        { page } { pretcurmark } { last }
-        {
-          \l_@@_fg_headline_child_style_tl 
-          \LastMark { pretcurmark }
-        }
-        {
-          \vbox_set:Nn \l_@@_fg_headline_parent_box 
-            { \l_@@_fg_headline_parent_style_tl \LastMark { pretprevmark } }
-          \vbox:n {
-            \skip_vertical:n { - \box_ht_plus_dp:N \l_@@_fg_headline_parent_box }
-            \l_@@_fg_headline_parent_style_tl \LastMark { pretprevmark }
-            \skip_vertical:N \c_zero_dim
-            \l_@@_fg_headline_child_style_tl \LastMark { pretcurmark }
+        \tl_if_eq:NNTF \l_@@_fg_headline_prev_title_tl
+          \l_@@_fg_headline_cur_title_tl
+          {
+            \l_@@_fg_headline_child_style_tl
+            \tl_use:N \l_@@_fg_headline_cur_title_tl
+          }
+          {
+            \vbox_set:Nn \l_@@_fg_headline_parent_box 
+              {
+                \l_@@_fg_headline_parent_style_tl
+                \tl_use:N \l_@@_fg_headline_prev_title_tl
+              }
+            \vbox:n {
+              \skip_vertical:n
+                { - \box_ht_plus_dp:N \l_@@_fg_headline_parent_box }
+              \l_@@_fg_headline_parent_style_tl
+              \tl_use:N \l_@@_fg_headline_prev_title_tl
+              \skip_vertical:N \c_zero_dim
+              \l_@@_fg_headline_child_style_tl
+              \tl_use:N \l_@@_fg_headline_cur_title_tl
+            }
           }
-        }
       }
     \group_end:
     \hfil
@@ -272,7 +264,7 @@
     \tl_if_eq:nnTF { #1 } { star }
       {
         \bool_set_true:N \l_@@_fg_headline_star_mark_bool
-        \InsertMark { pretstarmark } { #2 }
+        \tl_set:Nn \l_@@_fg_headline_star_title_tl { #2 }
       }
       {
         \bool_set_false:N \l_@@_fg_headline_star_mark_bool
@@ -287,12 +279,13 @@
               { \l_@@_fg_headline_cur_sec_lv_int } > 
               { \l_@@_fg_headline_prev_sec_lv_int }
               {
-                \InsertMark { pretprevmark } { \LastMark { pretcurmark } }
-                \InsertMark { pretcurmark } { #2 }
+                \tl_set_eq:NN \l_@@_fg_headline_prev_title_tl
+                  \l_@@_fg_headline_cur_title_tl
+                \tl_set:Nn \l_@@_fg_headline_cur_title_tl { #2 }
               }
               {
-                \InsertMark { pretprevmark } { #2 }
-                \InsertMark { pretcurmark } { #2 }
+                \tl_set:Nn \l_@@_fg_headline_prev_title_tl { #2 }
+                \tl_set:Nn \l_@@_fg_headline_cur_title_tl { #2 }
               }
             \int_set_eq:NN \l_@@_fg_headline_prev_sec_lv_int
               \l_@@_fg_headline_cur_sec_lv_int

testfiles/dual.lvt

@@ -25,6 +25,7 @@ Testing the text in the subsubsection.
 
 Testing the text in the paragraph.
 
+\section{New section}
 \subparagraph{A small point}
 
 Testing the text in the subparagraph.