l3 (7dec17)

git-svn-id: svn://tug.org/texlive/trunk@46003 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 299 insertions, 150 deletions

diff --git a/Master/texmf-dist/source/latex/l3kernel/l3basics.dtx b/Master/texmf-dist/source/latex/l3kernel/l3basics.dtx
index 078db9864a7..120abdb963c 100644
--- a/Master/texmf-dist/source/latex/l3kernel/l3basics.dtx
+++ b/Master/texmf-dist/source/latex/l3kernel/l3basics.dtx
@@ -7,7 +7,7 @@
 % 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
+%    https://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.
@@ -21,7 +21,7 @@
 % for those people who are interested.
 %
 %<*driver>
-\documentclass[full]{l3doc}
+\documentclass[full,kernel]{l3doc}
 \begin{document}
   \DocInput{\jobname.dtx}
 \end{document}
@@ -41,7 +41,7 @@
 %    }^^A
 % }
 %
-% \date{Released 2017/11/14}
+% \date{Released 2017/12/05}
 %
 % \maketitle
 %
@@ -1259,6 +1259,33 @@
 %   \cs{cs_if_exist_p:N}, and if not raises a kernel-level error.
 % \end{function}
 %
+% \begin{function}{\__debug_chk_var_scope:NN}
+%   \begin{syntax}
+%     \cs{__debug_chk_var_scope:NN} \meta{scope} \meta{var}
+%   \end{syntax}
+%   Checks the \meta{var} has the correct \meta{scope}, and if not
+%   raises a kernel-level error.  This function is only created if
+%   debugging is enabled.  The \meta{scope} is a single letter |l|, |g|,
+%   |c| denoting local variables, global variables, or constants.  More
+%   precisely, if the variable name starts with a letter and an
+%   underscore (normal \pkg{expl3} convention) the function checks that
+%   this single letter matches the \meta{scope}.  Otherwise the function
+%   cannot know the scope \meta{var} the first time: instead, it defines
+%   |\__debug_chk_/|\meta{var name} to store that information for the
+%   next call.  Thus, if a given \meta{var} is subject to assignments of
+%   different scopes a kernel error will result.
+% \end{function}
+%
+% \begin{function}{\__debug_chk_var_local:N, \__debug_chk_var_global:N}
+%   \begin{syntax}
+%     \cs{__debug_chk_var_local:N} \meta{var}
+%     \cs{__debug_chk_var_global:N} \meta{var}
+%   \end{syntax}
+%   Applies \cs{__debug_chk_var_exist:N} \meta{var}, then
+%   \cs{__debug_chk_var_scope:NN} \meta{scope} \meta{var}, where
+%   \meta{scope} is |l| or~|g|.
+% \end{function}
+%
 % \begin{function}{\__debug_log:x}
 %   \begin{syntax}
 %     \cs{__debug_log:x} \Arg{message text}
@@ -1269,15 +1296,6 @@
 %   This function is only created if debugging is enabled.
 % \end{function}
 %
-% \begin{function}{\__debug_suspend_log:, \__debug_resume_log:}
-%   \begin{syntax}
-%     \cs{__debug_suspend_log:} \ldots{} \cs{__debug_log:x} \ldots{} \cs{__debug_resume_log:}
-%   \end{syntax}
-%   Any \cs{__debug_log:x} command between \cs{__debug_suspend_log:} and
-%   \cs{__debug_resume_log:} is suppressed.  These two commands can be
-%   nested.  These functions are only created if debugging is enabled.
-% \end{function}
-%
 % \begin{function}{\__debug_patch:nnNNpn}
 %   \begin{syntax}
 %     \cs{__debug_patch:nnNNpn} \Arg{before} \Arg{after}
@@ -1331,6 +1349,25 @@
 %   counterpart.
 % \end{function}
 %
+% \begin{function}
+%   {\__debug_patch_args:nnnNNpn, \__debug_patch_conditional_args:nnnNNpnn}
+%   \begin{syntax}
+%     \cs{__debug_patch_args:nnnNNpn} \Arg{before} \Arg{after} \Arg{arguments}
+%     \meta{definition} \meta{function} \meta{parameters} \Arg{code}
+%   \end{syntax}
+%   A combination of \cs{__debug_patch:nnNNpn} and
+%   \cs{__debug_patch_args:nNNpn}.
+% \end{function}
+%
+% \begin{function}{\__kernel_check_defined:NT}
+%   \begin{syntax}
+%     \cs{__kernel_check_defined:NT} \meta{variable} \Arg{true code}
+%   \end{syntax}
+%   If \meta{variable} is not defined (according to
+%   \cs{cs_if_exist:NTF}), this triggers an error, otherwise the
+%   \meta{true code} is run.
+% \end{function}
+%
 % \begin{function}{\__kernel_register_show:N, \__kernel_register_show:c}
 %   \begin{syntax}
 %     \cs{__kernel_register_show:N} \meta{register}
@@ -1744,7 +1781,7 @@
 %<@@=debug>
 %    \end{macrocode}
 %
-% \begin{macro}[int]{\@@:TF}
+% \begin{macro}{\@@:TF}
 %   A more meaningful test of whether debugging is enabled than messing
 %   up with guards.  We can also more easily change the logic in one
 %   place then.  At present, debugging is disabled in the format and in
@@ -1798,15 +1835,59 @@
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}[aux]
+% \begin{macro}{\debug_suspend:, \debug_resume:}
+% \begin{macro}{\@@_suspended:T}
+% \begin{macro}{\l_@@_suspended_tl}
+%   Suspend and resume locally all debug-related errors and logging
+%   except deprecation errors.  The \cs{debug_suspend:} and \cs{debug_resume:}
+%   pairs can be nested.  We keep track of nesting in a token list
+%   containing a number of periods.  At first begin with the
+%   \enquote{non-suspended} version of \cs{@@_suspended:T}.
+%    \begin{macrocode}
+\@@:TF
+  {
+    \cs_set_nopar:Npn \l_@@_suspended_tl { }
+    \cs_set_protected:Npn \debug_suspend:
+      {
+        \tl_put_right:Nn \l_@@_suspended_tl { . }
+        \cs_set_eq:NN \@@_suspended:T \use:n
+      }
+    \cs_set_protected:Npn \debug_resume:
+      {
+        \tl_set:Nx \l_@@_suspended_tl
+          { \tl_tail:N \l_@@_suspended_tl }
+        \tl_if_empty:NT \l_@@_suspended_tl
+          {
+            \cs_set_eq:NN \@@_suspended:T \use_none:n
+          }
+      }
+    \cs_set:Npn \@@_suspended:T #1 { }
+  }
+  {
+    \cs_set_protected:Npn \debug_suspend: { }
+    \cs_set_protected:Npn \debug_resume: { }
+  }
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}
 %   {\@@_check-declarations_on:, \@@_check-declarations_off:}
-% \begin{macro}[int]{\@@_chk_var_exist:N}
-% \begin{macro}[int]{\@@_chk_cs_exist:N, \@@_chk_cs_exist:c}
-%   When debugging is enabled these two functions
-%   set up \cs{@@_chk_var_exist:N} and
-%   \cs{@@_chk_cs_exist:N}, two functions that test (when
-%   \texttt{check-declarations} is active) that their argument is
-%   defined.
+% \begin{macro}{\@@_chk_var_exist:N}
+% \begin{macro}{\@@_chk_cs_exist:N, \@@_chk_cs_exist:c}
+% \begin{macro}{\@@_chk_var_local:N, \@@_chk_var_global:N}
+% \begin{macro}{\@@_chk_var_scope:NN}
+%   When debugging is enabled these two functions set up functions that
+%   test their argument (when \texttt{check-declarations} is active)
+%   \begin{itemize}
+%     \item \cs{@@_chk_var_exist:N} and \cs{@@_chk_cs_exist:N}, two
+%       functions that test that their argument is defined;
+%     \item \cs{@@_chk_var_scope:NN} that checks that its argument |#2|
+%       has scope |#1|.
+%     \item \cs{@@_chk_var_local:N} and \cs{@@_chk_var_global:N} that
+%       perform both checks.
+%   \end{itemize}
 %    \begin{macrocode}
 \@@:TF
   {
@@ -1814,6 +1895,7 @@
       {
         \cs_set_protected:Npn \@@_chk_var_exist:N ##1
           {
+            \@@_suspended:T \use_none:nnn
             \cs_if_exist:NF ##1
               {
                 \__msg_kernel_error:nnx { kernel } { non-declared-variable }
@@ -1822,17 +1904,38 @@
           }
         \cs_set_protected:Npn \@@_chk_cs_exist:N ##1
           {
+            \@@_suspended:T \use_none:nnn
             \cs_if_exist:NF ##1
               {
                 \__msg_kernel_error:nnx { kernel } { command-not-defined }
                   { \token_to_str:N ##1 }
               }
           }
+        \cs_set_protected:Npn \@@_chk_var_scope:NN
+          {
+            \@@_suspended:T \use_none:nnn
+            \@@_chk_var_scope_aux:NN
+          }
+        \cs_set_protected:Npn \@@_chk_var_local:N ##1
+          {
+            \@@_suspended:T \use_none:nnnnn
+            \@@_chk_var_exist:N ##1
+            \@@_chk_var_scope_aux:NN l ##1
+          }
+        \cs_set_protected:Npn \@@_chk_var_global:N ##1
+          {
+            \@@_suspended:T \use_none:nnnnn
+            \@@_chk_var_exist:N ##1
+            \@@_chk_var_scope_aux:NN g ##1
+          }
       }
     \exp_args:Nc \cs_set_protected:Npn { @@_check-declarations_off: }
       {
         \cs_set_protected:Npn \@@_chk_var_exist:N ##1 { }
         \cs_set_protected:Npn \@@_chk_cs_exist:N ##1 { }
+        \cs_set_protected:Npn \@@_chk_var_local:N ##1 { }
+        \cs_set_protected:Npn \@@_chk_var_global:N ##1 { }
+        \cs_set_protected:Npn \@@_chk_var_scope:NN ##1##2 { }
       }
     \cs_set_protected:Npn \@@_chk_cs_exist:c
       { \exp_args:Nc \@@_chk_cs_exist:N }
@@ -1847,11 +1950,64 @@
 % \end{macro}
 % \end{macro}
 % \end{macro}
+% \end{macro}
+% \end{macro}
 %
-% \begin{macro}[aux]
+% \begin{macro}{\@@_chk_var_scope_aux:NN}
+% \begin{macro}{\@@_chk_var_scope_aux:Nn}
+% \begin{macro}{\@@_chk_var_scope_aux:NNn}
+%   First check whether the name of the variable |#2| starts with
+%   \meta{letter}|_|.  If it does then pass that letter, the
+%   \meta{scope}, and the variable name to
+%   \cs{@@_chk_var_scope_aux:NNn}.  That function compares the two
+%   letters and triggers an error if they differ (the \cs{scan_stop:}
+%   case is not reachable here).  If the second character was not |_|
+%   then pass the same data to the same auxiliary, except for its first
+%   argument which is now a control sequence.  That control sequence is
+%   actually a token list (but to avoid triggering the checking code we
+%   manipulate it using \cs{cs_set_nopar:Npn}) containing a single
+%   letter \meta{scope} according to what the first assignment to the
+%   given variable was.
+%    \begin{macrocode}
+\@@:TF
+  {
+    \cs_set_protected:Npn \@@_chk_var_scope_aux:NN #1#2
+      { \exp_args:NNf \@@_chk_var_scope_aux:Nn #1 { \cs_to_str:N #2 } }
+    \cs_set_protected:Npn \@@_chk_var_scope_aux:Nn #1#2
+      {
+        \if:w _ \use_i:nn \use_i_delimit_by_q_stop:nw #2 ? ? \q_stop
+          \exp_after:wN \@@_chk_var_scope_aux:NNn
+            \use_i_delimit_by_q_stop:nw #2 ? \q_stop
+            #1 {#2}
+        \else:
+          \exp_args:Nc \@@_chk_var_scope_aux:NNn
+            { @@_chk_/ #2 }
+            #1 {#2}
+        \fi:
+      }
+    \cs_set_protected:Npn \@@_chk_var_scope_aux:NNn #1#2#3
+      {
+        \if:w #1 #2
+        \else:
+          \if:w #1 \scan_stop:
+            \cs_gset_nopar:Npn #1 {#2}
+          \else:
+            \__msg_kernel_error:nnxxx { kernel } { local-global }
+              {#1} {#2} { \iow_char:N \\ #3 }
+          \fi:
+        \fi:
+      }
+  }
+  { }
+%    \end{macrocode}
+% \end{macro}
+% \end{macro}
+% \end{macro}
+%
+% \begin{macro}
 %   {\@@_check-expressions_on:, \@@_check-expressions_off:}
-% \begin{macro}[int]{\@@_chk_expr:nNnN}
-% \begin{macro}[aux]{\@@_chk_expr_aux:nNnN}
+% \begin{macro}{\@@_chk_expr:nNnN}
+% \begin{macro}{\@@_chk_expr_aux:nNnN}
 %   When debugging is enabled these two functions set
 %   \cs{@@_chk_expr:nNnN} to test or not whether the given
 %   expression is valid.  The idea is to evaluate the expression within
@@ -1877,6 +2033,7 @@
       {
         \cs_set:Npn \@@_chk_expr:nNnN ##1##2
           {
+            \@@_suspended:T { ##1 \use_none:nnnnnnn }
             \exp_after:wN \@@_chk_expr_aux:nNnN
             \exp_after:wN { \tex_the:D ##2 ##1 \tex_relax:D }
             ##2
@@ -1906,48 +2063,25 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[aux]{\@@_log-functions_on:, \@@_log-functions_off:}
-% \begin{macro}[int]{\@@_log:x, \@@_suspend_log:, \@@_resume_log:}
-%   These two functions
-%   (corresponding to the \pkg{expl3} option \texttt{log-functions})
-%   control whether \cs{@@_log:x} writes to the log file or not.
-%   Since \cs{iow_log:x} does not yet have its final definition we do
-%   not use \cs{cs_set_eq:NN} (not defined yet anyway).  The
-%   \cs{@@_suspend_log:} function disables \cs{@@_log:x} until
-%   the matching \cs{@@_resume_log:}.  These two commands are used
-%   to improve the logging for datatypes with multiple parts, currently
-%   only coffins.  They should come in pairs, which can be nested (this
-%   complicates the code here and is currently unused).  The function
-%   \cs{exp_not:o} is defined in \pkg{l3expan} later on but
-%   \cs{@@_suspend_log:} and \cs{@@_resume_log:} are not used
-%   before that point.  Once everything is defined, turn logging on or
-%   off depending on what option was given.
-%   When debugging is not enabled, simply produce an error.
+% \begin{macro}{\@@_log-functions_on:, \@@_log-functions_off:}
+% \begin{macro}{\@@_log:x}
+%   These two functions (corresponding to the \pkg{expl3} option
+%   \texttt{log-functions}) control whether \cs{@@_log:x} writes to the
+%   log file or not.  Since \cs{iow_log:x} does not yet have its final
+%   definition we do not use \cs{cs_set_eq:NN} (not defined yet anyway).
+%   Once everything is defined, turn logging on or off depending on what
+%   option was given.  When debugging is not enabled, simply produce an
+%   error.
 %    \begin{macrocode}
 \@@:TF
   {
     \exp_args:Nc \cs_set_protected:Npn { @@_log-functions_on: }
       {
-        \cs_set_protected:Npn \@@_log:x { \iow_log:x }
-        \cs_set_protected:Npn \@@_suspend_log:
-          {
-            \cs_set_protected:Npx \@@_resume_log:
-              {
-                \cs_set_protected:Npn \@@_resume_log:
-                  { \exp_not:o { \@@_resume_log: } }
-                \cs_set_protected:Npn \@@_log:x
-                  { \exp_not:o { \@@_log:x } }
-              }
-            \cs_set_protected:Npn \@@_log:x { \use_none:n }
-          }
-        \cs_set_protected:Npn \@@_resume_log: { }
+        \cs_set_protected:Npn \@@_log:x
+          { \@@_suspended:T \use_none:nn \iow_log:x }
       }
     \exp_args:Nc \cs_set_protected:Npn { @@_log-functions_off: }
-      {
-        \cs_set_protected:Npn \@@_log:x { \use_none:n }
-        \cs_set_protected:Npn \@@_suspend_log: { }
-        \cs_set_protected:Npn \@@_resume_log: { }
-      }
+      { \cs_set_protected:Npn \@@_log:x { \use_none:n } }
     \tex_ifodd:D \l@expl@log@functions@bool
       \use:c { @@_log-functions_on: }
     \else:
@@ -1963,7 +2097,7 @@
 % \begin{variable}{\g_@@_deprecation_on_tl, \g_@@_deprecation_off_tl}
 %   Some commands were more recently deprecated and not yet removed;
 %   only make these into errors if the user requests it.  This relies on
-%   two token lists, filled up by calls to
+%   two token lists, mostly filled up by calls to
 %   \cs{@@_deprecation:nnNNpn} in each module.
 %    \begin{macrocode}
 \@@:TF
@@ -1980,8 +2114,8 @@
 % \end{variable}
 % \end{macro}
 %
-% \begin{macro}[int]{\@@_deprecation:nnNNpn}
-% \begin{macro}[aux]{\@@_deprecation_aux:nnNnn}
+% \begin{macro}{\@@_deprecation:nnNNpn}
+% \begin{macro}{\@@_deprecation_aux:nnNnn}
 %   Grab a definition (at present, must be \cs{cs_new_protected:Npn}).
 %   Add to \cs{g_@@_deprecation_on_tl} some code that makes the
 %   defined macro |#3| outer (and defines it as an error).  Add to
@@ -2034,10 +2168,10 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[int]
+% \begin{macro}
 %   {\@@_patch:nnNNpn, \@@_patch_conditional:nNNpnn}
-% \begin{macro}[aux]
-%   {\@@_patch_aux:nnNNnn, \@@_patch_aux:nNNnnn}
+% \begin{macro}
+%   {\@@_patch_aux:nnnn, \@@_patch_auxii:nnnn}
 %   When debugging is not enabled, \cs{@@_patch:nnNNpn} and
 %   \cs{@@_patch_conditional:nNNpnn} throw the patch away.
 %   Otherwise they can be followed by \cs{cs_new:Npn} (or similar), and
@@ -2048,13 +2182,13 @@
 \@@:TF
   {
     \cs_set_protected:Npn \@@_patch:nnNNpn #1#2#3#4#5#
-      { \@@_patch_aux:nnNNnn {#1} {#2} #3 #4 {#5} }
+      { \@@_patch_aux:nnnn {#1} {#2} { #3 #4 #5 } }
     \cs_set_protected:Npn \@@_patch_conditional:nNNpnn #1#2#3#4#
-      { \@@_patch_aux:nNNnnn {#1} #2 #3 {#4} }
-    \cs_set_protected:Npn \@@_patch_aux:nnNNnn #1#2#3#4#5#6
-      { #3 #4 #5 { #1 #6 #2 } }
-    \cs_set_protected:Npn \@@_patch_aux:nNNnnn #1#2#3#4#5#6
-      { #2 #3 #4 {#5} { #1 #6 } }
+      { \@@_patch_auxii:nnnn {#1} { #2 #3 #4 } }
+    \cs_set_protected:Npn \@@_patch_aux:nnnn #1#2#3#4
+      { #3 { #1 #4 #2 } }
+    \cs_set_protected:Npn \@@_patch_auxii:nnnn #1#2#3#4
+      { #2 {#3} { #1 #4 } }
   }
   {
     \cs_set_protected:Npn \@@_patch:nnNNpn #1#2 { }
@@ -2064,48 +2198,57 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[int]
+% \begin{macro}
 %   {\@@_patch_args:nNNpn, \@@_patch_conditional_args:nNNpnn}
-% \begin{macro}[aux]
+% \begin{macro}
+%   {\@@_patch_args:nnnNNpn, \@@_patch_conditional_args:nnnNNpnn}
+% \begin{macro}
 %   {
 %     \@@_tmp:w,
-%     \@@_patch_args_aux:nNNnn,
-%     \@@_patch_args_aux:nNNnnn
+%     \@@_patch_args_aux:nnnNNnn,
+%     \@@_patch_args_aux:nnnNNnnn,
+%     \@@_patch_args_aux:nnnn
 %   }
 %   See \cs{@@_patch:nnNNpn}.  The first argument is something like
 %   |{#1}{(#2)}|.  Define a temporary macro using the \meta{parameters}
 %   and \meta{code} of the definition that follows, then expand that
 %   temporary macro in front of the first argument to obtain new
 %   \meta{code}.  Then perform the definition as if that new \meta{code}
-%   was directly typed in the file.  To make it easy to expand in the
-%   definition, treat it as a \enquote{pre}-code to an empty definition.
+%   was directly typed in the file.
 %    \begin{macrocode}
+\cs_set_protected:Npn \@@_patch_args:nNNpn
+  { \@@_patch_args:nnnNNpn { } { } }
+\cs_set_protected:Npn \@@_patch_conditional_args:nNNpnn
+  { \@@_patch_conditional_args:nnnNNpnn { } { } }
 \@@:TF
   {
-    \cs_set_protected:Npn \@@_patch_args:nNNpn #1#2#3#4#
-      { \@@_patch_args_aux:nNNnn {#1} #2 #3 {#4} }
-    \cs_set_protected:Npn \@@_patch_conditional_args:nNNpnn #1#2#3#4#
-      { \@@_patch_args_aux:nNNnnn {#1} #2 #3 {#4} }
-    \cs_set_protected:Npn \@@_patch_args_aux:nNNnn #1#2#3#4#5
+    \cs_set_protected:Npn \@@_patch_args:nnnNNpn #1#2#3#4#5#6#
+      { \@@_patch_args_aux:nnnNNnn {#1} {#2} {#3} #4 #5 {#6} }
+    \cs_set_protected:Npn \@@_patch_conditional_args:nnnNNpnn #1#2#3#4#5#6#
+      { \@@_patch_args_aux:nnnNNnnn {#1} {#2} {#3} #4 #5 {#6} }
+    \cs_set_protected:Npn \@@_patch_args_aux:nnnNNnn #1#2#3#4#5#6#7
       {
-        \cs_set:Npn \@@_tmp:w #4 {#5}
-        \exp_after:wN \@@_patch_aux:nnNNnn \exp_after:wN
-          { \@@_tmp:w #1 } { } #2 #3 {#4} { }
+        \cs_set:Npn \@@_tmp:w #6 {#7}
+        \exp_after:wN \@@_patch_args_aux:nnnn \exp_after:wN
+          { \@@_tmp:w #3 } { #4 #5 #6 } {#1} {#2}
       }
-    \cs_set_protected:Npn \@@_patch_args_aux:nNNnnn #1#2#3#4#5#6
+    \cs_set_protected:Npn \@@_patch_args_aux:nnnNNnnn #1#2#3#4#5#6#7#8
       {
-        \cs_set:Npn \@@_tmp:w #4 {#6}
-        \exp_after:wN \@@_patch_aux:nNNnnn \exp_after:wN
-          { \@@_tmp:w #1 } #2 #3 {#4} {#5} { }
+        \cs_set:Npn \@@_tmp:w #6 {#8}
+        \exp_after:wN \@@_patch_args_aux:nnnn \exp_after:wN
+          { \@@_tmp:w #3 } { #4 #5 #6 {#7} } {#1} {#2}
       }
+    \cs_set_protected:Npn \@@_patch_args_aux:nnnn #1#2#3#4
+      { #2 { #3 #1 #4 } }
   }
   {
-    \cs_set_protected:Npn \@@_patch_args:nNNpn #1 { }
-    \cs_set_protected:Npn \@@_patch_conditional_args:nNNpnn #1 { }
+    \cs_set_protected:Npn \@@_patch_args:nnnNNpn #1#2#3 { }
+    \cs_set_protected:Npn \@@_patch_conditional_args:nnnNNpnn #1#2#3 { }
   }
 %    \end{macrocode}
 % \end{macro}
 % \end{macro}
+% \end{macro}
 %
 % \subsection{Conditional processing and definitions}
 %
@@ -2161,7 +2304,7 @@
 %     \prg_set_protected_conditional:Npnn ,
 %     \prg_new_protected_conditional:Npnn ,
 %   }
-% \begin{macro}[aux]{\@@_generate_conditional_parm:nnNpnn}
+% \begin{macro}{\@@_generate_conditional_parm:nnNpnn}
 %   The user functions for the types using parameter text from the
 %   programmer. The various functions only differ by which function is
 %   used for the assignment. For those |Npnn| type functions, we must
@@ -2196,7 +2339,7 @@
 %     \prg_set_protected_conditional:Nnn ,
 %     \prg_new_protected_conditional:Nnn ,
 %   }
-% \begin{macro}[aux]
+% \begin{macro}
 %   {
 %     \@@_generate_conditional_count:nnNnn ,
 %     \@@_generate_conditional_count:nnNnnnn
@@ -2243,7 +2386,7 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[aux]
+% \begin{macro}
 %   {
 %     \@@_generate_conditional:nnNnnnnn,
 %     \@@_generate_conditional:nnnnnnw
@@ -2303,7 +2446,7 @@
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}[aux]
+% \begin{macro}
 %   {
 %     \@@_generate_p_form:wnnnnnn,
 %     \@@_generate_TF_form:wnnnnnn,
@@ -2359,7 +2502,7 @@
 % \end{macro}
 %
 % \begin{macro}{\prg_set_eq_conditional:NNn, \prg_new_eq_conditional:NNn}
-% \begin{macro}[aux]{\@@_set_eq_conditional:NNNn}
+% \begin{macro}{\@@_set_eq_conditional:NNNn}
 %   The setting-equal functions.  Split both functions and feed
 %   \Arg{name_1} \Arg{signature_1} \meta{boolean_1}
 %   \Arg{name_2} \Arg{signature_2} \meta{boolean_2}
@@ -2387,12 +2530,12 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[aux]
+% \begin{macro}
 %   {
 %     \@@_set_eq_conditional:nnNnnNNw ,
 %     \@@_set_eq_conditional_loop:nnnnNw
 %   }
-% \begin{macro}[aux, EXP]
+% \begin{macro}[EXP]
 %   {
 %     \@@_set_eq_conditional_p_form:nnn  ,
 %     \@@_set_eq_conditional_TF_form:nnn ,
@@ -2485,7 +2628,7 @@
 %    \end{macrocode}
 %
 % \begin{macro}[EXP]{\cs_to_str:N}
-% \begin{macro}[aux, EXP]{\@@_to_str:N, \@@_to_str:w}
+% \begin{macro}[EXP]{\@@_to_str:N, \@@_to_str:w}
 %   This converts a control sequence into the character string of its
 %   name, removing the leading escape character. This turns out to be
 %   a non-trivial matter as there a different cases:
@@ -2549,8 +2692,8 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[EXP, int]{\@@_split_function:NN}
-% \begin{macro}[aux, EXP]
+% \begin{macro}[EXP]{\@@_split_function:NN}
+% \begin{macro}[EXP]
 %   {\@@_split_function_auxi:w, \@@_split_function_auxii:w}
 %   This function takes a function name and splits it into name with
 %   the escape char removed and argument specification. In addition to
@@ -2597,7 +2740,7 @@
 % \end{macro}
 % \end{macro}
 %
-% \begin{macro}[EXP, int]
+% \begin{macro}[EXP]
 %   {\@@_get_function_name:N, \@@_get_function_signature:N}
 %   Simple wrappers.
 %    \begin{macrocode}
@@ -2736,7 +2879,7 @@
 %    us to generate error messages. The next few definitions here are
 %    only temporary, they will be redefined later on.
 %
-% \begin{macro}[int]
+% \begin{macro}
 %   {\__msg_kernel_error:nnxx, \__msg_kernel_error:nnx, \__msg_kernel_error:nn}
 %   If an internal error occurs before \LaTeX3 has loaded \pkg{l3msg} then
 %   the code should issue a usable if terse error message and halt. This
@@ -2784,7 +2927,7 @@
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}[int]{\__chk_if_free_cs:N, \__chk_if_free_cs:c}
+% \begin{macro}{\__chk_if_free_cs:N, \__chk_if_free_cs:c}
 %   This command is called by \cs{cs_new_nopar:Npn} and \cs{cs_new_eq:NN}
 %   \emph{etc.}\
 %   to make sure that the argument sequence is not already in use. If
@@ -2821,7 +2964,7 @@
 %     \cs_new_protected_nopar:Npn , \cs_new_protected_nopar:Npx ,
 %     \cs_new_protected:Npn       , \cs_new_protected:Npx
 %   }
-% \begin{macro}[int]{\@@_tmp:w}
+% \begin{macro}{\@@_tmp:w}
 %   Function which check that the control sequence is free before
 %   defining it.
 %     \begin{macrocode}
@@ -2996,8 +3139,8 @@
 %<@@=cs>
 %    \end{macrocode}
 %
-% \begin{macro}[int]{\@@_parm_from_arg_count:nnF}
-% \begin{macro}[aux]{\@@_parm_from_arg_count_test:nnF}
+% \begin{macro}{\@@_parm_from_arg_count:nnF}
+% \begin{macro}{\@@_parm_from_arg_count_test:nnF}
 %   \LaTeX3 provides shorthands to define control sequences and
 %   conditionals with a simple parameter text, derived directly from the
 %   signature, or more generally from knowing the number of arguments,
@@ -3015,7 +3158,7 @@
     \exp_args:Nx \@@_parm_from_arg_count_test:nnF
       {
         \exp_after:wN \exp_not:n
-        \if_case:w \__int_eval:w (#2) \__int_eval_end:
+        \if_case:w \__int_eval:n {#2}
              { }
         \or: { ##1 }
         \or: { ##1##2 }
@@ -3050,8 +3193,8 @@
 %<@@=cs>
 %    \end{macrocode}
 %
-% \begin{macro}[EXP, int]{\@@_count_signature:N, \@@_count_signature:c}
-% \begin{macro}[aux, EXP]{\@@_count_signature:nnN}
+% \begin{macro}[EXP]{\@@_count_signature:N, \@@_count_signature:c}
+% \begin{macro}[EXP]{\@@_count_signature:nnN}
 %   Counting the number of tokens in the signature, \emph{i.e.}, the
 %   number of arguments the function should take.  Since this is not
 %   used in any time-critical function, we simply use \cs{tl_count:n} if
@@ -3301,75 +3444,81 @@
 %<@@=kernel>
 %    \end{macrocode}
 %
-% \begin{macro}[int]{\@@_register_show:N, \@@_register_show:c}
-% \begin{macro}[aux]{\@@_register_show_aux:n}
+% \begin{macro}{\@@_check_defined:NT}
+%   Error if the variable |#1| is not defined.
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_check_defined:NT #1#2
+  {
+    \cs_if_exist:NTF #1
+      {#2}
+      {
+        \__msg_kernel_error:nnx { kernel } { variable-not-defined }
+          { \token_to_str:N #1 }
+      }
+  }
+%    \end{macrocode}
+% \end{macro}
+%
+% \begin{macro}
+%   {\@@_register_show:N, \@@_register_show:c, \@@_register_log:N, \@@_register_log:c}
+% \begin{macro}{\@@_register_show_aux:NN, \@@_register_show_aux:nNN}
 %   Simply using the \tn{showthe} primitive does not allow for
-%   line-wrapping, so instead use \cs{__msg_show_variable:NNNnn} (defined
-%   in \pkg{l3msg}).  This checks that the variable exists (using
-%   \cs{cs_if_exist:NTF}), then displays the third argument, namely
+%   line-wrapping, so instead use \cs{tl_show:n} and \cs{tl_log:n} (defined
+%   in \pkg{l3tl} and that performs line-wrapping).  This displays
 %   |>~|\meta{variable}|=|\meta{value}.  We expand the value before-hand
 %   as otherwise some integers (such as \tn{currentgrouplevel} or
 %   \tn{currentgrouptype}) altered by the line-wrapping code would show
 %   wrong values.
 %    \begin{macrocode}
-\cs_new_protected:Npn \@@_register_show:N #1
-  { \exp_args:No \@@_register_show_aux:nN { \tex_the:D #1 } #1 }
-\cs_new_protected:Npn \@@_register_show_aux:nN #1#2
-  {
-    \__msg_show_variable:NNNnn #2 \cs_if_exist:NTF ? { }
-      { > ~ \token_to_str:N #2 = #1 }
-  }
+\cs_new_protected:Npn \@@_register_show:N
+  { \@@_register_show_aux:NN \tl_show:n }
 \cs_new_protected:Npn \@@_register_show:c
   { \exp_args:Nc \@@_register_show:N }
-%    \end{macrocode}
-% \end{macro}
-% \end{macro}
-%
-% \begin{macro}[int]{\@@_register_log:N, \@@_register_log:c}
-%   Redirect the output of \cs{@@_register_show:N} to the log.
-%    \begin{macrocode}
 \cs_new_protected:Npn \@@_register_log:N
-  { \__msg_log_next: \@@_register_show:N }
+  { \@@_register_show_aux:NN \tl_log:n }
 \cs_new_protected:Npn \@@_register_log:c
   { \exp_args:Nc \@@_register_log:N }
+\cs_new_protected:Npn \@@_register_show_aux:NN #1#2
+  {
+    \@@_check_defined:NT #2
+      {
+        \exp_args:No \@@_register_show_aux:nNN
+          { \tex_the:D #2 } #2 #1
+      }
+  }
+\cs_new_protected:Npn \@@_register_show_aux:nNN #1#2#3
+  { \exp_args:No #3 { \token_to_str:N #2 = #1 } }
 %    \end{macrocode}
 % \end{macro}
+% \end{macro}
 %
-% \begin{macro}{\cs_show:N, \cs_show:c}
+% \begin{macro}{\cs_show:N, \cs_show:c, \cs_log:N, \cs_log:c, \@@_show:NN}
 %   Some control sequences have a very long name or meaning.  Thus,
 %   simply using \TeX{}'s primitive \tn{show} could lead to overlong
 %   lines.  The output of this primitive is mimicked to some extent,
-%   then the re-built string is given to \cs{iow_wrap:nnnN} for
+%   then the re-built string is given to \cs{tl_show:n} or \cs{tl_log:n} for
 %   line-wrapping.  We must expand the meaning before passing it to the
 %   wrapping code as otherwise we would wrongly see the definitions that
 %   are in place there.  To get correct escape characters, set the
 %   \tn{escapechar} in a group; this also localizes the assignment
-%   performed by \texttt{x}-expansion.  The \cs{cs_show:c} command also
-%   converts its argument to a control sequence within a group to avoid
+%   performed by \texttt{x}-expansion.  The \cs{cs_show:c} and \cs{cs_log:c} commands
+%   convert their argument to a control sequence within a group to avoid
 %   showing \tn{relax} for undefined control sequences.
 %    \begin{macrocode}
-\cs_new_protected:Npn \cs_show:N #1
+\cs_new_protected:Npn \cs_show:N { \@@_show:NN \tl_show:n }
+\cs_new_protected:Npn \cs_show:c
+  { \group_begin: \exp_args:NNc \group_end: \cs_show:N }
+\cs_new_protected:Npn \cs_log:N { \@@_show:NN \tl_log:n }
+\cs_new_protected:Npn \cs_log:c
+  { \group_begin: \exp_args:NNc \group_end: \cs_log:N }
+\cs_new_protected:Npn \@@_show:NN #1#2
   {
     \group_begin:
       \int_set:Nn \tex_escapechar:D { `\\ }
       \exp_args:NNx
     \group_end:
-    \__msg_show_wrap:n { > ~ \token_to_str:N #1 = \cs_meaning:N #1 }
+    #1 { \token_to_str:N #2 = \cs_meaning:N #2 }
   }
-\cs_new_protected:Npn \cs_show:c
-  { \group_begin: \exp_args:NNc \group_end: \cs_show:N }
-%    \end{macrocode}
-% \end{macro}
-%
-% \begin{macro}{\cs_log:N, \cs_log:c}
-%   Use \cs{cs_show:N} or \cs{cs_show:c} after calling
-%   \cs{__msg_log_next:} to redirect their output to the log file only.
-%   Note that \cs{cs_log:c} is not just a variant of \cs{cs_log:N} as
-%   the csname should be turned to a control sequence within a group
-%   (see \cs{cs_show:c}).
-%    \begin{macrocode}
-\cs_new_protected:Npn \cs_log:N { \__msg_log_next: \cs_show:N }
-\cs_new_protected:Npn \cs_log:c { \__msg_log_next: \cs_show:c }
 %    \end{macrocode}
 % \end{macro}
 %