l3experimental 3109 (29dec11)

git-svn-id: svn://tug.org/texlive/trunk@24970 c570f23f-e606-0410-a88d-b1316a301751

12 files changed, 1689 insertions, 837 deletions

diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3flag.sty b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3flag.sty
new file mode 100644
index 00000000000..40e2c899682
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3flag.sty
@@ -0,0 +1,100 @@
+%%
+%% This is file `l3flag.sty',
+%% generated with the docstrip utility.
+%%
+%% The original source files were:
+%%
+%% l3flag.dtx  (with options: `package')
+%% 
+%% EXPERIMENTAL CODE
+%% 
+%% Do not distribute this file without also distributing the
+%% source files specified above.
+%% 
+%% Do not distribute a modified version of this file.
+%% 
+%% File: l3flag.dtx Copyright (C) 2011 The LaTeX3 Project
+%%
+%% It may be distributed and/or modified under the conditions of the
+%% LaTeX Project Public License (LPPL), either version 1.3c of this
+%% 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
+%%
+%% This file is part of the "l3experimental bundle" (The Work in LPPL)
+%% and all files in that bundle must be distributed together.
+%%
+%% The released version of this bundle is available from CTAN.
+%%
+%% -----------------------------------------------------------------------
+%%
+%% The development version of the bundle can be found at
+%%
+%%    http://www.latex-project.org/svnroot/experimental/trunk/
+%%
+%% for those people who are interested.
+%%
+%%%%%%%%%%%
+%% NOTE: %%
+%%%%%%%%%%%
+%%
+%%   Snapshots taken from the repository represent work in progress and may
+%%   not work or may contain conflicting material!  We therefore ask
+%%   people _not_ to put them into distributions, archives, etc. without
+%%   prior consultation with the LaTeX3 Project.
+%%
+%% -----------------------------------------------------------------------
+\RequirePackage{expl3}
+\GetIdInfo$Id: l3flag.dtx 3039 2011-12-08 09:22:35Z bruno $
+  {L3 Experimental Flags}
+\ProvidesExplPackage
+  {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription}
+\tl_new:N \g_flag_list_tl
+\cs_new_protected:Npn \flag_new:N #1
+  {
+    \tl_if_in:NnTF \g_flag_list_tl {#1}
+      {
+        \msg_kernel_error:nnx
+          { flag } { already-defined }
+          { \token_to_str:N #1 }
+      }
+      {
+        \tl_gput_right:Nn \g_flag_list_tl {#1}
+        \cs_new_eq:NN #1 \c_undefined:D
+      }
+  }
+\cs_generate_variant:Nn \flag_new:N { c }
+\prg_new_conditional:Npnn \flag_test:N #1 { p , T , F , TF }
+  {
+    \if_cs_exist:N #1
+      \prg_return_true:
+    \else:
+      \prg_return_false:
+    \fi:
+  }
+\prg_new_conditional:Npnn \flag_test:c #1 { p , T , F , TF }
+  {
+    \if_cs_exist:w #1 \cs_end:
+      \prg_return_true:
+    \else:
+      \prg_return_false:
+    \fi:
+  }
+\cs_new:Npn \flag_raise:N #1
+  { \exp_after:wN \use_none:n \cs:w \cs_to_str:N #1 \cs_end: }
+\cs_new:Npn \flag_raise:c #1
+  { \exp_after:wN \use_none:n \cs:w #1 \cs_end: }
+\cs_new_protected:Npn \flag_lower:N #1
+  { \cs_set_eq:NN #1 \c_undefined:D }
+\cs_generate_variant:Nn \flag_lower:N { c }
+\msg_kernel_new:nnnn { flag } { already-defined }
+  { The~control~sequence~#1~is~already~declared~as~a~flag. }
+  {
+    LaTeX~was~asked~to~define~the~flag~#1,~but~it~has~already~
+    been~defined~as~a~flag.~The~flag~module~is~mostly~meant~
+    for~kernel~use,~and~booleans~should~be~preferred.
+  }
+%% 
+%%
+%% End of file `l3flag.sty'.
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3regex.sty b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3regex.sty
index f3dc0b5a358..facf764c168 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3regex.sty
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3regex.sty
@@ -46,17 +46,19 @@
 %%
 %% -----------------------------------------------------------------------
 \RequirePackage{expl3}
-\GetIdInfo$Id: l3regex.dtx 3017 2011-11-28 00:10:02Z bruno $
+\GetIdInfo$Id: l3regex.dtx 3073 2011-12-21 01:53:06Z bruno $
   {L3 Experimental Regular Expressions}
 \ProvidesExplPackage
   {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription}
-\RequirePackage{l3str}
+\RequirePackage{l3str, l3tl-analysis, l3flag}
 \cs_new:Npn \regex_tmp:w { }
-\tl_new:N   \g_regex_tmpa_tl
 \tl_new:N   \l_regex_tmpa_tl
 \tl_new:N   \l_regex_tmpb_tl
+\tl_new:N   \l_regex_tmpc_tl
 \int_new:N  \l_regex_tmpa_int
 \int_new:N  \l_regex_tmpb_int
+\flag_new:N \l_regex_group_begin_flag
+\flag_new:N \l_regex_group_end_flag
 \int_new:N  \l_regex_max_state_int
 \int_new:N  \l_regex_left_state_int
 \int_new:N  \l_regex_right_state_int
@@ -67,7 +69,10 @@
 \int_new:N  \l_regex_capturing_group_int
 \seq_new:N  \l_regex_capturing_group_seq
 \int_new:N  \l_regex_capturing_group_max_int
+\tl_new:N \l_regex_build_or_class_tl
 \tl_new:N   \l_regex_one_or_group_tl
+\bool_new:N \l_regex_in_csname_bool
+\tl_new:N \l_regex_tmpa_regex_tl
 \cs_new_eq:NN \regex_build_tmp_class:n \use_none:n
 \bool_new:N \l_regex_class_bool
 \tl_new:N   \l_regex_class_tl
@@ -133,12 +138,16 @@
     \regex_item_geq:n { \c_eleven } % > lf
     \regex_item_range:nn { \c_zero } { \c_nine } % < lf
   }
-\tl_new:N \l_regex_query_other_str
+\int_new:N \l_regex_nesting_int
+\int_new:N \l_regex_min_step_int
+\int_new:N \l_regex_max_step_int
 \int_new:N \l_regex_current_step_int
 \int_new:N \l_regex_start_step_int
 \int_new:N \l_regex_success_step_int
-\int_new:N \l_regex_unique_step_int
+\int_new:N \l_regex_unique_id_int
 \int_new:N \l_regex_current_char_int
+\int_new:N \l_regex_current_catcode_int
+\tl_new:N \l_regex_current_token_tl
 \int_new:N \l_regex_last_char_int
 \int_new:N \l_regex_case_changed_char_int
 \bool_new:N \l_regex_caseless_bool
@@ -147,23 +156,23 @@
 \prop_new:N \l_regex_success_submatches_prop
 \int_new:N \l_regex_max_index_int
 \tl_new:N \l_regex_every_match_tl
-\bool_new:N \l_regex_success_bool
+\bool_new:N \g_regex_success_bool
+\bool_new:N \l_regex_saved_success_bool
+\bool_new:N \l_regex_success_match_bool
 \cs_new_protected:Npn \regex_last_match_empty_no:F #1 {#1}
 \cs_new_protected:Npn \regex_last_match_empty_yes:F
   { \int_compare:nNnF \l_regex_start_step_int = \l_regex_current_step_int }
 \cs_new_eq:NN \regex_last_match_empty:F \regex_last_match_empty_no:F
 \bool_new:N \l_regex_success_empty_bool
 \bool_new:N \l_regex_fresh_thread_bool
-\seq_new:N  \g_regex_submatches_seq
-\int_new:N \g_regex_match_count_int
-\seq_new:N \g_regex_extract_all_seq
-\seq_new:N \g_regex_split_seq
-\tl_new:N \l_regex_replacement_tl
-\tl_new:N \g_regex_replaced_str
-\cs_new_eq:NN \s_regex_stop \scan_stop:
+\int_new:N \l_regex_replacement_int
+\int_new:N \l_regex_replacement_csnames_int
+\int_new:N \l_regex_submatch_int
+\int_new:N \l_regex_submatch_start_int
+\int_new:N \l_regex_match_count_int
 \cs_new_protected:Npn \regex_toks_put_left:Nx #1#2
   {
-    \cs_set_nopar:Npx \regex_tmp:w \s_regex_stop { \s_regex_stop #2 }
+    \cs_set_nopar:Npx \regex_tmp:w \s_stop { \s_stop #2 }
     \tex_toks:D #1 \exp_after:wN \exp_after:wN \exp_after:wN
       { \exp_after:wN \regex_tmp:w \tex_the:D \tex_toks:D #1 }
   }
@@ -173,18 +182,24 @@
     \tex_toks:D #1 \exp_after:wN
       { \tex_the:D \tex_toks:D \exp_after:wN #1 \regex_tmp:w }
   }
-\cs_new_nopar:Npn \regex_query_substr:NN #1#2
+\cs_new:Npn \regex_query_substr:nn #1#2
   {
-    \exp_after:wN \regex_query_substr_aux:NN
-    \exp_after:wN #1
-    \exp_after:wN #2
-    \l_regex_query_other_str
-    \q_stop
+    \if_num:w \int_eval:w #1 < \int_eval:w #2 \int_eval_end:
+      \str_aux_toks_range:nn {#1} {#2}
+    \fi:
+  }
+\cs_new:Npn \regex_query_submatch:nn #1#2
+  {
+    \if_num:w #1 < \l_regex_capturing_group_int
+      \exp_after:wN \regex_query_submatch:w
+      \int_use:N \int_eval:w #1 + #2 ;
+    \fi:
   }
-\cs_new:Npn \regex_query_substr_aux:NN #1#2
+\cs_new:Npn \regex_query_submatch:w #1 ;
   {
-    \str_skip_do:nn {#1}
-      { \str_collect_do:nn { #2 - #1 } { \use_i_delimit_by_q_stop:nw } }
+    \regex_query_substr:nn
+      { \tex_skip:D #1 }
+      { \etex_gluestretch:D \tex_skip:D #1 }
   }
 \cs_new_protected:Npn \regex_seq_pop_int:NN #1#2
   {
@@ -208,8 +223,27 @@
     \seq_get:NN #1 \l_regex_tmpa_tl
     \l_regex_tmpa_tl
   }
+\cs_new:Npn \regex_seq_item:Nn #1#2
+  {
+    \exp_after:wN \regex_seq_item_aux:wNn
+    \int_use:N \int_eval:w #2 \exp_after:wN ;
+    #1 { ? \prg_map_break: } { }
+    \prg_break_point:n { }
+  }
+\cs_new:Npn \regex_seq_item_aux:wNn #1; #2#3
+  {
+    \use_none:n #2
+    \if_num:w #1 = \c_zero
+      \exp_after:wN \prg_map_break:n
+    \else:
+      \exp_after:wN \use_none:n
+    \fi:
+    { \exp_not:n {#3} }
+    \exp_after:wN \regex_seq_item_aux:wNn
+    \int_use:N \int_eval:w #1 - \c_one ;
+  }
 \cs_new_protected_nopar:Npn \regex_item_dot:T
-  { \int_compare:nNnF \l_regex_current_char_int = \c_minus_one }
+  { \int_compare:nNnF \l_regex_current_char_int < \c_minus_one }
 \cs_new_protected_nopar:Npn \regex_break_true:w
    #1 \regex_break_point:TF #2 #3 {#2}
 \cs_new_protected_nopar:Npn \regex_break_false:w
@@ -283,6 +317,37 @@
     \cs_set:Npn \regex_item_range:nn { \regex_item_caseful_range:nn }
     \cs_set:Npn \regex_item_geq:n    { \regex_item_caseful_geq:n }
   }
+\cs_new_protected_nopar:Npn \regex_item_catcode:n #1
+  {
+    \if_num:w #1 = \l_regex_current_catcode_int
+      \exp_after:wN \regex_break_true:w
+    \fi:
+  }
+\cs_new_protected_nopar:Npn \regex_item_catcode_neq:n #1
+  {
+    \if_num:w #1 = \l_regex_current_catcode_int
+    \else:
+      \exp_after:wN \regex_break_true:w
+    \fi:
+  }
+\cs_new_protected:Npn \regex_item_cs:n #1
+  {
+    \int_compare:nNnT \l_regex_current_catcode_int = \c_zero
+      {
+        \tl_set:Nn \l_regex_tmpa_regex_tl {#1}
+        \bool_set_eq:NN \l_regex_saved_success_bool \g_regex_success_bool
+        \exp_args:NNx \regex_match:NnTF \l_regex_tmpa_regex_tl
+          {
+            \exp_after:wN \exp_after:wN
+            \exp_after:wN \cs_to_str:N \l_regex_current_token_tl
+          }
+          {
+            \bool_gset_eq:NN \g_regex_success_bool \l_regex_saved_success_bool
+            \regex_break_true:w
+          }
+          { \bool_gset_eq:NN \g_regex_success_bool \l_regex_saved_success_bool }
+      }
+  }
 \cs_new_protected:Npn \regex_get_digits:nw #1
   {
     \tex_afterassignment:D \regex_tmp:w
@@ -362,14 +427,10 @@
   }
 \cs_new_protected_nopar:Npn \regex_build_new_state:
   {
-    \int_compare:nNnTF \l_regex_max_state_int > { 32766 }
-      { \msg_error:nn { regex } { -997 } }
-      {
-        \int_incr:N \l_regex_max_state_int
-        \tex_toks:D \l_regex_max_state_int { \s_regex_stop }
-      }
+    \tex_toks:D \l_regex_max_state_int { \s_stop }
     \int_set_eq:NN \l_regex_left_state_int \l_regex_right_state_int
     \int_set_eq:NN \l_regex_right_state_int \l_regex_max_state_int
+    \int_incr:N \l_regex_max_state_int
   }
 \cs_new_protected_nopar:Npn \regex_build_transition_aux:NN #1#2
   {
@@ -388,16 +449,18 @@
   }
 \cs_new_protected:Npn \regex_build:n #1
   {
-    \regex_build_setup:
-    \str_aux_escape:NNNn
-      \regex_build_i_unescaped:N
-      \regex_build_i_escaped:N
-      \regex_build_i_raw:N
-      { #1 }
+    \bool_set_false:N \l_regex_in_csname_bool
+    \regex_build:w
+    \regex_build_new_state:
+    \regex_toks_put_right:Nx \l_regex_left_state_int
+      { \regex_action_start_wildcard:nn {0} {1} }
     \regex_build_open_aux:
-      \g_str_result_tl \prg_do_nothing: \prg_do_nothing:
-    \regex_seq_push_int:NN \l_regex_capturing_group_seq \c_zero
-    \regex_build_close_aux: \regex_build_group_:
+      \str_escape_use:NNNn
+        \regex_build_i_unescaped:N
+        \regex_build_i_escaped:N
+        \regex_build_i_raw:N
+        { #1 }
+      \prg_do_nothing: \prg_do_nothing:
     \regex_build_end:
   }
 \cs_new_nopar:Npn \regex_build_i_unescaped:N #1
@@ -414,38 +477,39 @@
   }
 \cs_new_nopar:Npn \regex_build_i_raw:N #1
   { \exp_not:N \regex_build_raw:N #1 }
-\cs_new_protected_nopar:Npn \regex_build_default_control:N #1
+\cs_new_protected_nopar:Npn \regex_build_control:N #1
   {
-    \cs_if_exist_use:cF { regex_build_#1: }
-      { \regex_build_default_raw:N #1 }
+    \cs_if_exist_use:cF { regex_ \l_regex_build_or_class_tl _#1: }
+      { \use:c { regex_ \l_regex_build_or_class_tl _default_raw:N } #1 }
   }
-\cs_new_protected_nopar:Npn \regex_build_setup:
+\cs_new_protected_nopar:Npn \regex_build:w
   {
-    \cs_set_eq:NN \regex_build_control:N \regex_build_default_control:N
     \cs_set_eq:NN \regex_build_raw:N \regex_build_default_raw:N
+    \tl_set:Nn \l_regex_build_or_class_tl { build }
     \int_set_eq:NN \l_regex_capturing_group_int \c_zero
     \int_zero:N \l_regex_max_state_int
     \regex_build_new_state:
-    \regex_build_new_state:
-    \regex_toks_put_right:Nx \l_regex_left_state_int
-      { \regex_action_start_wildcard:nn {0} {1} }
   }
 \cs_new_protected_nopar:Npn \regex_build_end:
   {
+    \regex_seq_push_int:NN \l_regex_capturing_group_seq \c_zero
+    \regex_build_close_aux: \regex_build_group_:
     \seq_if_empty:NF \l_regex_capturing_group_seq
       {
-        \msg_error:nn { regex } {22}
+        \msg_kernel_error:nnx { regex } { missing-rparen }
+          { \seq_length:N \l_regex_capturing_group_seq }
         \prg_replicate:nn
           { \seq_length:N \l_regex_capturing_group_seq }
           { \regex_build_close_aux: \regex_build_group_: }
       }
     \regex_toks_put_right:Nx \l_regex_right_state_int
       { \regex_action_success: }
+    \int_incr:N \l_regex_capturing_group_int
   }
 \cs_new_protected_nopar:cpn { regex_build_^: }
-  { \regex_build_anchor_start:N \c_zero }
+  { \regex_build_anchor_start:N \l_regex_min_step_int }
 \cs_new_protected_nopar:Npn \regex_build_A:
-  { \regex_build_anchor_start:N \c_zero }
+  { \regex_build_anchor_start:N \l_regex_min_step_int }
 \cs_new_protected_nopar:Npn \regex_build_G:
   { \regex_build_anchor_start:N \l_regex_start_step_int }
 \cs_new_protected_nopar:Npn \regex_build_anchor_start:N #1
@@ -453,7 +517,7 @@
     \regex_build_new_state:
     \regex_toks_put_right:Nx \l_regex_left_state_int
       {
-        \exp_not:N \int_compare:nNnT {#1} = \l_regex_current_step_int
+        \exp_not:N \int_compare:nNnT #1 = \l_regex_current_step_int
           {
             \regex_action_free:n
               {
@@ -469,7 +533,7 @@
     \regex_toks_put_right:Nx \l_regex_left_state_int
       {
         \exp_not:N \int_compare:nNnT
-          \c_minus_one = \l_regex_current_char_int
+          \l_regex_current_char_int < \c_minus_one
           {
             \regex_action_free:n
               {
@@ -519,61 +583,52 @@
       \int_set_eq:NN \l_regex_current_char_int \l_regex_last_char_int
       \c_regex_w_tl
       \regex_break_point:TF
-        { \group_end: \c_regex_W_tl \regex_item_equal:n { -1 } }
+        { \group_end: \c_regex_W_tl \regex_item_equal:n { -2 } }
         { \group_end: \c_regex_w_tl }
     \regex_break_point:TF
   }
-\cs_new_protected_nopar:Npn \regex_build_default_raw:N #1
+\cs_new_protected:Npn \regex_build_one:n #1
+  { \regex_build_one:x { \exp_not:n {#1} } }
+\cs_new_protected:Npn \regex_build_one:x #1
   {
-    \cs_set:Npx \regex_build_tmp_class:n ##1
+    \cs_set_nopar:Npx \regex_build_tmp_class:n ##1
       {
-        \regex_item_equal:n { \int_value:w `#1 ~ }
-        \regex_break_point:TF { \regex_action_cost:n { ##1 } } { }
+        \exp_not:N \exp_not:n {#1}
+        \regex_break_point:TF { \regex_action_cost:n {##1} } { }
       }
     \regex_build_one_quantifier:
   }
+\cs_new_protected_nopar:Npn \regex_build_default_raw:N #1
+  { \regex_build_one:x { \regex_item_equal:n { \int_value:w `#1 ~ } } }
 \cs_new_protected_nopar:cpn { regex_build_.: }
   {
     \cs_set:Npn \regex_build_tmp_class:n ##1
       { \regex_item_dot:T { \regex_action_cost:n {##1} } }
     \regex_build_one_quantifier:
   }
-\cs_new_protected_nopar:Npn \regex_build_char_type:N #1
-  {
-    \cs_set:Npn \regex_build_tmp_class:n ##1
-      {
-        \exp_not:N #1
-        \regex_break_point:TF { \regex_action_cost:n {##1} } { }
-      }
-    \regex_build_one_quantifier:
-  }
 \tl_map_inline:nn { dDhHsSvVwWN }
   {
     \cs_new_protected_nopar:cpx { regex_build_#1: }
-      {
-        \exp_not:N \regex_build_char_type:N
-        \exp_not:c { c_regex_#1_tl }
-      }
+      { \regex_build_one:n \exp_not:c { c_regex_#1_tl } }
   }
+\cs_new_protected:Npn \regex_class_one:n
+  { \tl_put_right:Nn \l_regex_class_tl }
+\cs_new_protected:Npn \regex_class_one:x
+  { \tl_put_right:Nx \l_regex_class_tl }
 \cs_new_protected_nopar:cpn { regex_build_[: }
   {
     \tl_clear:N \l_regex_class_tl
-    \cs_set_eq:NN \regex_build_control:N \regex_class_control:N
-    \cs_set_eq:NN \regex_build_raw:N \regex_class_raw:N
+    \cs_set_eq:NN \regex_build_raw:N \regex_class_default_raw:N
+    \tl_set:Nn \l_regex_build_or_class_tl { class }
     \regex_class_first:NN
   }
-\cs_new_protected_nopar:Npn \regex_class_control:N #1
-  {
-    \cs_if_exist_use:cF { regex_class_#1: }
-      { \regex_class_raw:N #1 }
-  }
 \cs_new_protected_nopar:cpn { regex_class_]: }
   {
     \tl_if_empty:NTF \l_regex_class_tl %[
-      { \regex_class_raw:N ] }
+      { \regex_class_default_raw:N ] }
       {
-        \cs_set_eq:NN \regex_build_control:N \regex_build_default_control:N
         \cs_set_eq:NN \regex_build_raw:N  \regex_build_default_raw:N
+        \tl_set:Nn \l_regex_build_or_class_tl { build }
         \cs_set:Npn \regex_build_tmp_class:n ##1
           {
             \exp_not:o \l_regex_class_tl
@@ -593,7 +648,7 @@
         #1 #2
       }
   }
-\cs_new_protected_nopar:Npn \regex_class_raw:N #1#2#3
+\cs_new_protected_nopar:Npn \regex_class_default_raw:N #1#2#3
   {
     \str_if_eq:nnTF {#2#3} { \regex_build_control:N - }
       { \regex_class_range:Nw #1 }
@@ -603,10 +658,7 @@
       }
   }
 \cs_new_protected_nopar:Npn \regex_class_single:N #1
-  {
-    \tl_put_right:Nx \l_regex_class_tl
-      { \regex_item_equal:n { \int_value:w `#1 } }
-  }
+  { \regex_class_one:x { \regex_item_equal:n { \int_value:w `#1 } } }
 \cs_new_protected_nopar:Npn \regex_class_range:Nw #1#2#3
   {
     \token_if_eq_meaning:NNTF #2 \regex_build_control:N
@@ -624,9 +676,9 @@
 \cs_new_protected_nopar:Npn \regex_class_range_put:NN #1#2
   {
     \if_num:w `#1 > `#2 \exp_stop_f:
-      \msg_error:nn { regex } {8}
+      \msg_kernel_error:nnxx { regex } { backwards-range } {#1} {#2}
     \else:
-      \tl_put_right:Nx \l_regex_class_tl
+      \regex_class_one:x
         {
           \if_num:w `#1 = `#2 \exp_stop_f:
             \regex_item_equal:n
@@ -640,10 +692,93 @@
 \tl_map_inline:nn { dDhHsSvVwWN }
   {
     \cs_new_protected_nopar:cpx { regex_class_#1: }
+      { \regex_class_one:n \exp_not:c { c_regex_#1_tl } }
+  }
+\cs_new_protected_nopar:Npn \regex_build_c:
+  { \regex_aux_c:NNNN \regex_item_catcode:n \use_i:nn }
+\cs_new_protected_nopar:Npn \regex_build_C:
+  { \regex_aux_c:NNNN \regex_item_catcode_neq:n \use_ii:nn }
+\cs_new_eq:NN \regex_class_c: \regex_build_c:
+\cs_new_eq:NN \regex_class_C: \regex_build_C:
+\cs_new_protected:Npn \regex_aux_c:NNNN #1#2#3#4
+  {
+    \token_if_eq_meaning:NNTF #3 \regex_build_raw:N
+      {
+        \regex_aux_c_test:NTF #4
+          {
+            \use:c { regex_ \l_regex_build_or_class_tl _one:x }
+              { #1 { \int_use:N \l_regex_current_catcode_int } }
+          }
+          {
+            \msg_kernel_error:nnx { regex } { build-c } { #4 }
+            #3 #4
+          }
+      }
+      {
+        \if_charcode:w \c_lbrace_str \exp_not:N #4
+          \exp_after:wN #2
+        \else:
+          \exp_after:wN \use_ii:nn
+        \fi:
+        {
+          \group_begin:
+            \bool_set_true:N \l_regex_in_csname_bool
+            \regex_build:w
+        }
+        {
+          \msg_kernel_error:nnx { regex } { build-c } { #4 }
+          #3 #4
+        }
+      }
+  }
+\cs_new_protected:Npn \regex_aux_c_test:NTF #1
+  {
+    \int_set:Nn \l_regex_current_catcode_int
+      {
+        \if_case:w \int_eval:w `#1 - `A \int_eval_end:
+             \c_thirteen % Active
+        \or: \c_one      % Begin-group
+        \or: \c_zero     % Control sequence
+        \or: \c_eight    % Down (subscript)
+        \or: \c_two      % End-group
+        \else:
+          \if_case:w \int_eval:w `#1 - `L \int_eval_end:
+               \c_eleven    % Letter
+          \or: \c_three     % Math toggle
+          \or: \c_minus_one
+          \or: \c_twelve    % Other
+          \or: \c_six       % Parameter
+          \or: \c_minus_one
+          \or: \c_minus_one
+          \or: \c_ten       % Space
+          \or: \c_four      % Tab (alignment)
+          \or: \c_seven     % Up (superscript)
+          \else: \c_minus_one
+          \fi:
+        \fi:
+      }
+    \if_num:w \l_regex_current_catcode_int = \c_minus_one
+      \exp_after:wN \use_ii:nn
+    \else:
+      \exp_after:wN \use_i:nn
+    \fi:
+  }
+\cs_new_protected:cpn { regex_build_ \c_rbrace_str : }
+  {
+    \bool_if:NTF \l_regex_in_csname_bool
       {
-        \tl_put_right:Nn \exp_not:N \l_regex_class_tl
-          { \exp_not:c { c_regex_#1_tl } }
+        \regex_build_Z:
+        \regex_toks_put_right:Nx \l_regex_right_state_int
+          { \regex_action_success: }
+        \int_incr:N \l_regex_capturing_group_int
+        \use:x
+          {
+            \group_end:
+              \exp_not:n { \use:c { regex_ \l_regex_build_or_class_tl _one:n } }
+              { \regex_item_cs:n { \regex_set_aux:N ? } }
+          }
       }
+      { \exp_after:wN \regex_build_raw:N \c_rbrace_str }
   }
 \cs_new_protected_nopar:Npn \regex_build_quantifier:w #1#2
   {
@@ -711,12 +846,8 @@
       {
         \tl_if_empty:nTF {#2}
           { \regex_build_quantifier_aux:nnNN { {#1} } { n* } }
-          {
-            \int_compare:nNnT {#1} > {#2}
-              { \msg_error:nn { regex } {4} }
-            \regex_build_quantifier_aux:nnNN { {#1} {#2} } { nn }
-          }
-      }
+          { \regex_build_quantifier_aux:nnNN { {#1} {#2} } { nn } }
+      } %^^A todo: catch the case m>n
       {
         \regex_build_quantifier_end:n { }
         \use:x
@@ -833,7 +964,7 @@
 \cs_new_protected_nopar:cpn { regex_build_): }
   {
     \seq_if_empty:NTF \l_regex_capturing_group_seq
-      { \msg_error:nn { regex } { 22 } }
+      { \msg_kernel_error:nn { regex } { extra-rparen } }
       {
         \regex_build_close_aux:
         \regex_build_group_quantifier:
@@ -878,7 +1009,8 @@
   {
     \cs_if_exist_use:cF { regex_build_special_group_\token_to_str:N #2 : }
       {
-        \msg_error:nn { regex } { -998 }
+        \msg_kernel_error:nnx { regex } { unsupported }
+          { (? \token_to_str:N #2 } %)
         \regex_build_control:N ( % )
         \regex_build_raw:N ?
         #1 #2
@@ -990,7 +1122,7 @@
       {
         \tex_toks:D \l_regex_tmpa_int
           {
-            \s_regex_stop
+            \s_stop
             #1 { \int_eval:n { \l_regex_right_state_int - \l_regex_tmpa_int } }
           }
       }
@@ -1052,16 +1184,19 @@
     \regex_toks_put_right:Nx \l_regex_right_state_int
       {
         \regex_action_free:n
-          { \int_eval:n { \l_regex_max_state_int - \l_regex_left_state_int } }
+          {
+            \int_eval:n %^^A todo: document why that value.
+              { \l_regex_max_state_int - \c_one - \l_regex_left_state_int }
+          }
       }
     \int_set_eq:NN \l_regex_tmpa_int \l_regex_left_state_int
-    \int_set:Nn \l_regex_tmpb_int { \l_regex_max_state_int + \c_one }
+    \int_set_eq:NN \l_regex_tmpb_int \l_regex_max_state_int
     \int_set:Nn \l_regex_max_state_int
       {
-        \l_regex_left_state_int - \c_one
-        + #1 * ( \l_regex_max_state_int - \l_regex_left_state_int + \c_one )
+        \l_regex_left_state_int
+        + #1 * ( \l_regex_max_state_int - \l_regex_left_state_int )
       }
-    \int_until_do:nNnn \l_regex_tmpb_int > \l_regex_max_state_int
+    \int_while_do:nNnn \l_regex_tmpb_int < \l_regex_max_state_int
       {
         \tex_toks:D \l_regex_tmpb_int = \tex_toks:D \l_regex_tmpa_int
         \int_incr:N \l_regex_tmpa_int
@@ -1114,14 +1249,13 @@
 \cs_new_protected_nopar:Npn \regex_state_use_with_submatches:
   { \regex_state_use_aux:n { } }
 \cs_new_protected_nopar:Npn \regex_state_use:
-  { \regex_state_use_aux:n { \exp_after:wN \regex_state_use_aux_ii:w } }
-\cs_new_nopar:Npn \regex_state_use_aux_ii:w #1 \s_regex_stop { }
+  { \regex_state_use_aux:n { \exp_after:wN \use_none_delimit_by_s_stop:w } }
 \cs_new_protected_nopar:Npn \regex_state_use_aux:n #1
   {
     \if_num:w \tex_dimen:D \l_regex_current_state_int
-        < \l_regex_unique_step_int
+        < \l_regex_unique_id_int
       \tex_dimen:D \l_regex_current_state_int
-        = \l_regex_unique_step_int sp \scan_stop:
+        = \l_regex_unique_id_int sp \scan_stop:
       #1 \tex_the:D \tex_toks:D \exp_after:wN \l_regex_current_state_int
     \fi:
     \scan_stop:
@@ -1144,73 +1278,105 @@
         \tex_the:D \tex_toks:D #1
       }
   }
-\cs_new_protected:Npn \regex_store_submatches_aux:w #1 \s_regex_stop
+\cs_new_protected:Npn \regex_store_submatches_aux:w #1 \s_stop
   {
     \regex_store_submatches_aux_ii:Nnnw
       #1
       \regex_state_submatches:nn \c_minus_one \q_prop
-    \s_regex_stop
+    \s_stop
   }
 \cs_new_protected:Npn \regex_store_submatches_aux_ii:Nnnw
-    \regex_state_submatches:nn #1 #2 #3 \s_regex_stop
+    \regex_state_submatches:nn #1 #2 #3 \s_stop
   {
     \exp_after:wN \c_zero
     \exp_after:wN \regex_state_submatches:nn \exp_after:wN
       {
         \int_value:w \int_eval:w
-          \l_regex_unique_step_int + \c_one
+          \l_regex_unique_id_int + \c_one
         \exp_after:wN
       }
       \exp_after:wN { \l_regex_current_submatches_prop }
     \regex_state_submatches:nn {#1} {#2}
-    \s_regex_stop
+    \s_stop
   }
 \cs_new_protected:Npn \regex_state_submatches:nn #1#2
   {
-    \if_num:w #1 = \l_regex_unique_step_int
+    \if_num:w #1 = \l_regex_unique_id_int
       \tl_set:Nn \l_regex_current_submatches_prop { #2 }
     \fi:
   }
 \cs_new_protected:Npn \regex_match:n #1
   {
-    \tl_set:Nx \l_regex_query_other_str { \tl_to_other_str:n {#1} }
+    \tl_set_analysis:Nn \l_regex_tmpa_tl {#1}
+
+    \int_zero:N \l_regex_nesting_int
+    \int_set_eq:NN \l_regex_current_step_int \l_regex_max_state_int
+    \regex_query_set:nnn { } { -1 } { -2 }
+    \int_set_eq:NN \l_regex_min_step_int \l_regex_current_step_int
+    \exp_after:wN \regex_query_set_loop:ww
+      \l_regex_tmpa_tl
+      \q_mark { ? \prg_map_break: } ,
+    \prg_break_point:n { }
+    \int_set_eq:NN \l_regex_max_step_int \l_regex_current_step_int
+    \regex_query_set:nnn { } { -1 } { -2 }
+
     \regex_match_initial_setup:
     \regex_match_once:
   }
-\cs_new_protected_nopar:Npn \regex_match_once:
+\cs_new:Npn \regex_query_set_loop:ww #1 \q_mark #2#3 ,
   {
-    \regex_match_setup:
-    \exp_after:wN \regex_match_once_aux: \l_regex_query_other_str
-      \q_recursion_tail \q_recursion_stop
-    \bool_if:NT \l_regex_success_bool { \l_regex_every_match_tl }
+    \use_none:n #2
+    \regex_query_set:nnn {#1} {"#2} {#3}
+    \if_case:w "#2 \exp_stop_f:
+    \or: \int_incr:N \l_regex_nesting_int
+    \or: \int_decr:N \l_regex_nesting_int
+    \fi:
+    \regex_query_set_loop:ww
   }
-\cs_new_protected_nopar:Npn \regex_match_once_aux:
+\cs_new_protected:Npn \regex_query_set:nnn #1#2#3
   {
-    \int_compare:nNnTF \l_regex_start_step_int = \c_zero
-      {
-        \int_set_eq:NN \l_regex_current_char_int \c_minus_one
-        \regex_match_loop:N
-      }
-      {
-        \str_skip_do:nn
-          { \l_regex_start_step_int - \c_one }
-          { \regex_match_once_aux_ii:N }
-      }
+    \tex_muskip:D \l_regex_current_step_int
+      = \etex_gluetomu:D
+        #3 sp
+        plus #2 sp
+        minus \l_regex_nesting_int sp
+      \scan_stop:
+    \tex_toks:D \l_regex_current_step_int {#1}
+    \int_incr:N \l_regex_current_step_int
   }
-\cs_new_protected_nopar:Npn \regex_match_once_aux_ii:N #1
+\cs_new_protected_nopar:Npn \regex_query_get:
   {
-    \int_set:Nn \l_regex_current_char_int { `#1 }
-    \regex_match_loop:N
+    \tl_set:Nx \l_regex_current_token_tl
+      { \tex_the:D \tex_toks:D \l_regex_current_step_int }
+    \l_regex_current_char_int
+      = \etex_mutoglue:D \tex_muskip:D \l_regex_current_step_int
+    \l_regex_current_catcode_int = \etex_gluestretch:D
+      \etex_mutoglue:D \tex_muskip:D \l_regex_current_step_int
+  }
+\cs_new_protected_nopar:Npn \regex_match_once:
+  {
+    \regex_match_setup:
+    \regex_query_get:
+    \regex_match_loop:
+    \prg_break_point:n { }
+    \bool_if:NT \l_regex_success_match_bool
+      {
+        \bool_gset_true:N \g_regex_success_bool
+        \l_regex_every_match_tl
+      }
   }
 \cs_new_protected_nopar:Npn \regex_match_initial_setup:
   {
-    \prg_stepwise_inline:nnnn {1} {1} { \l_regex_max_state_int }
+    \prg_stepwise_inline:nnnn {0} {1} { \l_regex_max_state_int - \c_one }
       { \tex_dimen:D ##1 \c_minus_one sp \scan_stop: }
-    \int_set_eq:NN \l_regex_unique_step_int  \c_minus_one
-    \int_set_eq:NN \l_regex_start_step_int   \c_minus_one
-    \int_set_eq:NN \l_regex_current_step_int \c_zero
-    \int_set_eq:NN \l_regex_success_step_int \c_zero
+    \int_set_eq:NN \l_regex_unique_id_int  \c_minus_one
+    \int_set:Nn \l_regex_start_step_int
+      { \l_regex_min_step_int - \c_one }
+    \int_set_eq:NN \l_regex_current_step_int \l_regex_min_step_int
+    \int_set_eq:NN \l_regex_success_step_int \l_regex_min_step_int
+    \int_set_eq:NN \l_regex_submatch_int \l_regex_max_state_int
     \bool_set_false:N \l_regex_success_empty_bool
+    \bool_gset_false:N \g_regex_success_bool
   }
 \cs_new_protected_nopar:Npn \regex_match_setup:
   {
@@ -1219,33 +1385,44 @@
       { \cs_set_eq:NN \regex_last_match_empty:F \regex_last_match_empty_yes:F }
       { \cs_set_eq:NN \regex_last_match_empty:F \regex_last_match_empty_no:F }
     \int_set_eq:NN \l_regex_start_step_int \l_regex_success_step_int
-    \int_set_eq:NN \l_regex_current_step_int \l_regex_start_step_int
-    \int_decr:N \l_regex_current_step_int
-    \bool_set_false:N \l_regex_success_bool
+    \int_set:Nn \l_regex_current_step_int
+      { \l_regex_start_step_int - \c_one }
+    \bool_set_false:N \l_regex_success_match_bool
     \int_zero:N \l_regex_max_index_int
-    \regex_store_state:n {1}
+    \regex_store_state:n {0} %^^A _state_int!
   }
-\cs_new_protected_nopar:Npn \regex_match_loop:N #1
+\cs_new_protected_nopar:Npn \regex_match_loop:
   {
-    \regex_match_loop_setup:N #1
+    \int_incr:N \l_regex_current_step_int
+    \int_incr:N \l_regex_unique_id_int
+    \bool_set_false:N \l_regex_fresh_thread_bool
+    \int_set_eq:NN \l_regex_last_char_int \l_regex_current_char_int
+    \regex_query_get:
+    \regex_match_loop_case_hook:
     \cs_set_nopar:Npx \regex_tmp:w
       {
         \int_zero:N \l_regex_max_index_int
-        \prg_stepwise_function:nnnN
-          {1} {1} { \l_regex_max_index_int }
-          \regex_match_one_index:n
+        \regex_match_one_index:w 1 ; \prg_break_point:n { }
+        \exp_not:N \prg_break_point:n { }
       }
-    \regex_tmp:w \prg_break_point:n { }
+    \regex_tmp:w
+    \if_num:w \l_regex_current_char_int < \c_minus_one
+      \exp_after:wN \prg_map_break:
+    \fi:
     \if_num:w \l_regex_max_index_int = \c_zero
-      \exp_after:wN \use_none_delimit_by_q_recursion_stop:w
+      \exp_after:wN \prg_map_break:
     \fi:
-    \quark_if_recursion_tail_stop:N #1
-    \regex_match_loop:N
+    \regex_match_loop:
   }
-\cs_new_nopar:Npn \regex_match_one_index:n #1
+\cs_new_nopar:Npn \regex_match_one_index:w #1;
   {
+    \if_num:w #1 > \l_regex_max_index_int
+      \exp_after:wN \prg_map_break:
+    \fi:
     \regex_match_one_index_aux:n
       { \int_value:w \tex_skip:D #1 }
+    \exp_after:wN \regex_match_one_index:w
+    \int_use:N \int_eval:w #1 + \c_one ;
   }
 \cs_new_protected_nopar:Npn \regex_match_one_index_aux:n #1
   {
@@ -1253,19 +1430,6 @@
     \prop_clear:N \l_regex_current_submatches_prop
     \regex_state_use_with_submatches:
   }
-\cs_new_protected_nopar:Npn \regex_match_loop_setup:N #1
-  {
-    \int_incr:N \l_regex_current_step_int
-    \int_incr:N \l_regex_unique_step_int
-    \bool_set_false:N \l_regex_fresh_thread_bool
-    \int_set_eq:NN \l_regex_last_char_int \l_regex_current_char_int
-    \if_meaning:w #1 \q_recursion_tail
-      \int_set_eq:NN \l_regex_current_char_int \c_minus_one
-    \else:
-      \int_set:Nn \l_regex_current_char_int {`#1}
-    \fi:
-    \regex_match_loop_case_hook:
-  }
 \cs_new_protected_nopar:Npn \regex_match_loop_case_hook: { }
 \cs_new_protected_nopar:Npn \regex_match_loop_caseless_hook:
   {
@@ -1293,18 +1457,17 @@
   }
 \cs_new_protected_nopar:Npn \regex_action_cost:n #1
   {
-    \exp_args:Nf \regex_store_state:n %^^A optimize!
+    \exp_args:Nf \regex_store_state:n
       { \int_eval:n { \l_regex_current_state_int + #1 } }
   }
 \cs_new_protected_nopar:Npn \regex_action_success:
   {
     \regex_last_match_empty:F
       {
-        \bool_set_true:N \l_regex_success_bool
+        \bool_set_true:N \l_regex_success_match_bool
         \bool_set_eq:NN \l_regex_success_empty_bool
           \l_regex_fresh_thread_bool
-        \int_set_eq:NN \l_regex_success_step_int
-          \l_regex_current_step_int
+        \int_set_eq:NN \l_regex_success_step_int \l_regex_current_step_int
         \prop_set_eq:NN \l_regex_success_submatches_prop
           \l_regex_current_submatches_prop
         \prg_map_break:
@@ -1328,504 +1491,668 @@
     \prop_put:Nno \l_regex_current_submatches_prop {#1}
       { \int_use:N \l_regex_current_step_int }
   }
-\cs_new_protected_nopar:Npn \regex_extract:
+\cs_new_protected:Npn \regex_submatch_nesting_aux:n #1
   {
-    \seq_gclear:N \g_regex_submatches_seq
-    \prg_stepwise_inline:nnnn
-      {0} {1} { \l_regex_capturing_group_int }
-      {
-        \regex_extract_aux:nTF { ##1 }
-          {
-            \seq_gput_right:Nx \g_regex_submatches_seq
-              { \regex_query_substr:NN \l_regex_tmpa_tl \l_regex_tmpb_tl }
-          }
-          { \seq_gput_right:Nn \g_regex_submatches_seq { } }
-      }
+    + \etex_glueshrink:D \etex_mutoglue:D \etex_muexpr:D
+        \tex_muskip:D \etex_gluestretch:D \tex_skip:D #1
+        - \tex_muskip:D \tex_skip:D #1
+    \scan_stop:
   }
-\cs_new_protected_nopar:Npn \regex_extract_aux:nTF #1#2#3
+\cs_new:Npn \regex_nesting:n #1 { } %^^A move. Rename?
+\tl_new:N \l_regex_nesting_tl
+\cs_new_protected:Npn \regex_replacement:n #1
   {
-    \prop_get:NnNTF \l_regex_success_submatches_prop
-      { #1 < } \l_regex_tmpa_tl
+    \int_zero:N \l_regex_replacement_int
+    \int_zero:N \l_regex_nesting_int
+    \tl_clear:N \l_regex_nesting_tl
+    \str_escape_use:NNNn
+      \regex_replacement_unescaped:N
+      \regex_replacement_escaped:N
+      \regex_replacement_raw:N
+      {#1}
+    \prg_do_nothing: \prg_do_nothing:
+    \cs_set_nopar:Npx \regex_nesting:n ##1
+      {
+        + \int_use:N \l_regex_nesting_int
+        \l_regex_nesting_tl
+        - \regex_submatch_nesting_aux:n {##1}
+      }
+    \use:x
       {
-        \prop_get:NnNTF \l_regex_success_submatches_prop
-          { #1 > } \l_regex_tmpb_tl
-          {#2}
-          {#3}
+        \exp_not:n { \cs_set_nopar:Npn \regex_replacement_tl:n ##1 }
+          { \str_aux_toks_range:nn \c_zero \l_regex_replacement_int }
       }
-      {#3}
+      % ^^A rename! Careful with \cP\#.
   }
-\cs_new_protected_nopar:Npn \regex_set:Nn
-  { \regex_set_aux:NNn \tl_set_eq:NN }
-\cs_new_protected_nopar:Npn \regex_gset:Nn
-  { \regex_set_aux:NNn \tl_gset_eq:NN }
-\cs_new_protected:Npn \regex_set_aux:NNn #1#2#3
+\cs_new_protected:Npn \regex_replacement_raw:N #1
+  { \regex_replacement_put:n {#1} }
+\cs_new_protected:Npn \regex_replacement_put:n #1
   {
-    \group_begin:
-      \regex_build:n {#3}
-      \tl_gset:Nx \g_regex_tmpa_tl
-        {
-          \exp_not:N \regex_nfa:Nw \exp_not:N #2
-          \l_regex_max_state_int
-            = \int_use:N \l_regex_max_state_int
-          \l_regex_capturing_group_int
-            = \int_use:N \l_regex_capturing_group_int
-          \token_if_eq_meaning:NNT
-            \regex_match_loop_case_hook:
-            \regex_match_loop_caseless_hook:
-            {
-              \cs_set_eq:NN \regex_match_loop_case_hook:
-                \regex_match_loop_caseless_hook:
-            }
-          \prg_stepwise_function:nnnN
-            {1} {1} {\l_regex_max_state_int}
-            \regex_set_aux:n
-          \s_regex_stop
-        }
-    \group_end:
-    #1 #2 \g_regex_tmpa_tl
+    \tex_toks:D \l_regex_replacement_int {#1}
+    \int_incr:N \l_regex_replacement_int
   }
-\cs_new_nopar:Npn \regex_set_aux:n #1
-  { \tex_toks:D #1 { \tex_the:D \tex_toks:D #1 } }
-\cs_new:Npn \regex_nfa:Nw #1 #2 \s_regex_stop
-  { \msg_expandable_kernel_error:nnn { regex } { nfa-misused } {#1} }
-\cs_new_protected_nopar:Npn \regex_const:Nn
-  { \regex_set_aux:NNn \cs_new_eq:NN }
-\prg_new_protected_conditional:Npnn \regex_check_nfa:N #1 { T , TF }
-  { \exp_after:wN \regex_check_nfa_aux:Nw #1 \q_stop }
-\cs_new:Npn \regex_check_nfa_aux:Nw #1 #2 \q_stop
+\cs_new_protected:Npn \regex_replacement_unescaped:N #1
   {
-    \if_meaning:w \regex_nfa:Nw #1
-      \prg_return_true:
+    \if_charcode:w \c_rbrace_str #1
+      \if_num:w \l_regex_replacement_csnames_int > \c_zero
+        \regex_replacement_put:n \cs_end:
+      \else:
+        \regex_replacement_put:n #1
+      \fi:
     \else:
-      \msg_error:nnx { regex } { not-nfa } { \token_to_str:N #1 }
-      \prg_return_false:
+      \regex_replacement_put:n #1
     \fi:
   }
-\cs_new_protected_nopar:Npn \regex_use:N #1
-  { \exp_after:wN \use_none:nn #1 }
-\cs_new_protected:Npn \regex_user_aux:n #1
+\cs_new_protected:Npn \regex_replacement_escaped:N #1
   {
-    \group_begin:
-      \tl_clear:N \l_regex_every_match_tl
-      #1
-    \group_end:
-  }
-\cs_new_protected_nopar:Npn \regex_return_after_group:
-  {
-    \if_meaning:w \c_true_bool \l_regex_success_bool
-      \group_insert_after:N \prg_return_true:
+    \if_charcode:w c #1
+      \exp_after:wN \regex_replacement_c:w
     \else:
-      \group_insert_after:N \prg_return_false:
+      \if_charcode:w g #1
+        \exp_after:wN \exp_after:wN \exp_after:wN \regex_replacement_g:w
+      \else:
+        \if_num:w \c_one < 1#1 \exp_stop_f:
+          \regex_replacement_put_submatch:n {#1}
+        \else:
+          \regex_replacement_put:n #1
+        \fi:
+      \fi:
     \fi:
   }
-\cs_new_protected_nopar:Npn \regex_extract_after_group:N #1
+\cs_new_protected:Npn \regex_replacement_put_submatch:n #1
   {
-    \if_meaning:w \c_true_bool \l_regex_success_bool
-      \regex_extract:
-      \group_insert_after:N \seq_set_eq:NN
-      \group_insert_after:N #1
-      \group_insert_after:N \g_regex_submatches_seq
+    \regex_replacement_put:n
+      { \regex_query_submatch:nn {#1} {##1} }
+    \if_num:w \l_regex_replacement_csnames_int = \c_zero
+      \tl_put_right:Nn \l_regex_nesting_tl
+        {
+          \exp_not:N \if_num:w #1 < \l_regex_capturing_group_int
+            \regex_submatch_nesting_aux:n { \int_eval:w #1+##1 \int_eval_end: }
+          \exp_not:N \fi:
+        }
     \fi:
   }
-\cs_new_protected_nopar:Npn \regex_count_after_group:N #1
+\cs_new_protected:Npn \regex_replacement_error:NNN #1#2#3
   {
-    \group_insert_after:N \int_set_eq:NN
-    \group_insert_after:N #1
-    \group_insert_after:N \g_regex_match_count_int
+    \msg_kernel_error:nn { regex } { replacement-#1 }
+    #2 #3
   }
-\prg_new_protected_conditional:Npnn \regex_match:nn #1#2 { T , F , TF }
+\cs_new_protected:Npn \regex_replacement_g:w #1#2
   {
-    \regex_user_aux:n
+    \str_if_eq:xxTF
+      { \exp_not:n { #1#2 } }
+      { \regex_replacement_unescaped:N \c_lbrace_str }
       {
-        \regex_disable_submatches:
-        \regex_build:n {#1}
-        \regex_match:n {#2}
-        \regex_return_after_group:
+        \int_zero:N \l_regex_tmpa_int
+        \regex_replacement_g_digits:NN
       }
+      { \regex_replacement_error:NNN g #1 #2 }
   }
-\prg_new_protected_conditional:Npnn \regex_match:Nn #1#2 { T , F , TF }
+\cs_new_protected:Npn \regex_replacement_g_digits:NN #1#2
   {
-    \regex_check_nfa:NTF #1
+    \token_if_eq_meaning:NNTF #1 \regex_replacement_unescaped:N
       {
-        \regex_user_aux:n
-          {
-            \regex_disable_submatches:
-            \regex_use:N #1
-            \regex_match:n {#2}
-            \regex_return_after_group:
-          }
+        \if_num:w \c_one < 1#2 \exp_stop_f:
+          \int_set:Nn \l_regex_tmpa_int { \c_ten * \l_regex_tmpa_int + #2 }
+          \exp_after:wN \use_i:nnn
+          \exp_after:wN \regex_replacement_g_digits:NN
+        \else:
+          \if_charcode:w \c_rbrace_str #2
+            \exp_args:No \regex_replacement_put_submatch:n
+              { \int_use:N \l_regex_tmpa_int }
+            \exp_after:wN \exp_after:wN \exp_after:wN \use_none:nn
+          \else:
+            \exp_after:wN \exp_after:wN
+            \exp_after:wN \regex_replacement_error:NNN
+            \exp_after:wN \exp_after:wN \exp_after:wN g
+          \fi:
+        \fi:
       }
-      { \prg_return_false: }
+      { \regex_replacement_error:NNN g }
+    #1 #2
   }
-\cs_new_protected:Npn \regex_count:nnN #1#2#3
+\cs_new_protected_nopar:Npn \regex_replacement_c:w #1#2
   {
-    \regex_user_aux:n
+    \token_if_eq_meaning:NNTF #1 \regex_replacement_unescaped:N
       {
-        \regex_disable_submatches:
-        \int_gzero:N \g_regex_match_count_int
-        \tl_set:Nn \l_regex_every_match_tl
-          {
-            \int_gincr:N \g_regex_match_count_int
-            \regex_match_once:
-          }
-        \regex_build:n {#1}
-        \regex_match:n {#2}
-        \regex_count_after_group:N #3
+        \cs_if_exist_use:cF { regex_replacement_c_#2:w }
+          { \regex_replacement_error:NNN c #1#2 }
       }
+      { \regex_replacement_error:NNN c #1#2 }
   }
-\cs_new_protected:Npn \regex_count:NnN #1#2#3
+\cs_new_protected_nopar:cpn { regex_replacement_c_ \c_lbrace_str :w }
   {
-    \regex_check_nfa:NT #1
-      {
-        \regex_user_aux:n
-          {
-            \regex_disable_submatches:
-            \int_gzero:N \g_regex_match_count_int
-            \tl_set:Nn \l_regex_every_match_tl
-              {
-                \int_gincr:N \g_regex_match_count_int
-                \regex_match_once:
-              }
-            \regex_use:N #1
-            \regex_match:n {#2}
-            \regex_count_after_group:N #3
-          }
-      }
+    \int_incr:N \l_regex_replacement_csnames_int
+    \regex_replacement_put:n
+      { \exp_not:n { \exp_after:wN \regex_replacement_exp_not:N \cs:w } }
   }
-\cs_new_protected:Npn \regex_extract_once:nnN #1#2#3
-  {
-    \regex_user_aux:n
-      {
-        \regex_build:n {#1}
-        \regex_match:n {#2}
-        \regex_extract_after_group:N #3
-      }
+\cs_new_nopar:Npn \regex_replacement_exp_not:N #1 { \exp_not:n {#1} }
+\group_begin:
+
+  \char_set_catcode_math_superscript:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_U:w
+    { \regex_replacement_char:nNN { ^^@ } }
+
+  \char_set_catcode_alignment:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_T:w
+    { \regex_replacement_char:nNN { ^^@ } }
+
+  \cs_new_protected_nopar:Npn \regex_replacement_c_S:w #1#2
+    {
+      \int_compare:nNnTF { `#2 } = \c_zero
+        { \regex_replacement_error:NNN c #1#2 }
+        {
+          \char_set_lccode:nn {32} { `#2 }
+          \tl_to_lowercase:n { \regex_replacement_put:n {~} }
+        }
+    }
+
+  \char_set_catcode_parameter:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_P:w
+    { \regex_replacement_char:nNN { ^^@^^@ } }
+
+  \char_set_catcode_other:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_O:w
+    { \regex_replacement_char:nNN { ^^@ } }
+
+  \char_set_catcode_math_toggle:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_M:w
+    { \regex_replacement_char:nNN { ^^@ } }
+
+  \char_set_catcode_letter:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_L:w
+    { \regex_replacement_char:nNN { ^^@ } }
+
+  \char_set_catcode_group_end:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_E:w
+    {
+      \int_decr:N \l_regex_nesting_int
+      \regex_replacement_char:nNN { \if_false: { \fi:  ^^@ }
+    }
+
+  \char_set_catcode_math_subscript:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_D:w
+    { \regex_replacement_char:nNN { ^^@ } }
+
+  \char_set_catcode_group_begin:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_B:w
+    {
+      \int_incr:N \l_regex_nesting_int
+      \regex_replacement_char:nNN { \exp_after:wN ^^@ \if_false: } \fi: }
+    }
+
+  \char_set_catcode_active:N \^^@
+  \cs_new_protected_nopar:Npn \regex_replacement_c_A:w
+    { \regex_replacement_char:nNN { \exp_not:N ^^@ } }
+
+\group_end:
+
+\cs_new_protected_nopar:Npn \regex_replacement_char:nNN #1#2#3
+  {
+    \char_set_lccode:nn \c_zero { `#3 }
+    \tl_to_lowercase:n
+      { \regex_replacement_put:n { \exp_not:n {#1} } }
   }
-\prg_new_protected_conditional:Npnn \regex_extract_once:nnN #1#2#3
-  { T , F , TF }
+\cs_new_protected_nopar:Npn \regex_set:Nn
+  { \regex_set_aux:NNn \tl_set:Nn }
+\cs_new_protected_nopar:Npn \regex_gset:Nn
+  { \regex_set_aux:NNn \tl_gset:Nn }
+\cs_new_protected_nopar:Npn \regex_const:Nn
+  { \regex_set_aux:NNn \tl_const:Nn }
+\cs_new_protected:Npn \regex_set_aux:NNn #1#2#3
   {
-    \regex_user_aux:n
-      {
-        \regex_build:n {#1}
-        \regex_match:n {#2}
-        \regex_extract_after_group:N #3
-        \regex_return_after_group:
-      }
+    \group_begin:
+      \regex_build:n {#3}
+      \cs_set_nopar:Npx \regex_tmp:w
+        { #1 \exp_not:N #2 { \regex_set_aux:N #2 } }
+      \exp_after:wN
+    \group_end:
+    \regex_tmp:w
   }
-\cs_new_protected:Npn \regex_extract_once:NnN #1#2#3
+\cs_new:Npn \regex_set_aux:N #1
   {
-    \regex_check_nfa:NT #1
+    \exp_not:n { \regex_nfa:Nw #1 }
+    \l_regex_max_state_int
+      = \int_use:N \l_regex_max_state_int
+    \l_regex_capturing_group_int
+      = \int_use:N \l_regex_capturing_group_int
+    \token_if_eq_meaning:NNT
+      \regex_match_loop_case_hook:
+      \regex_match_loop_caseless_hook:
       {
-        \regex_user_aux:n
-          {
-            \regex_use:N #1
-            \regex_match:n {#2}
-            \regex_extract_after_group:N #3
-          }
+        \cs_set_eq:NN \regex_match_loop_case_hook:
+          \regex_match_loop_caseless_hook:
       }
+    \prg_stepwise_function:nnnN
+      {0} {1} {\l_regex_max_state_int - \c_one }
+      \regex_set_aux:n
+    \s_stop
   }
-\prg_new_protected_conditional:Npnn \regex_extract_once:NnN #1#2#3
-  { T , F , TF }
+\cs_new_nopar:Npn \regex_set_aux:n #1
+  { \tex_toks:D #1 { \tex_the:D \tex_toks:D #1 } }
+\cs_new:Npn \regex_nfa:Nw #1
   {
-    \regex_check_nfa:NTF #1
-      {
-        \regex_user_aux:n
-          {
-            \regex_use:N #1
-            \regex_match:n {#2}
-            \regex_extract_after_group:N #3
-            \regex_return_after_group:
-          }
-      }
-      { \prg_return_false: }
+    \msg_expandable_kernel_error:nnn { regex } { nfa-misused } {#1}
+    \use_none_delimit_by_s_stop:w
   }
-\cs_new_protected:Npn \regex_extract_all:nnN #1#2#3
+\cs_new_protected_nopar:Npn \regex_use:N
+  { \exp_last_unbraced:No \use_none:nn }
+\cs_new_nopar:Npn \regex_to_str:N #1
   {
-    \regex_user_aux:n
-      {
-        \seq_gclear:N \g_regex_extract_all_seq
-        \tl_set:Nn \l_regex_every_match_tl { \regex_extract_all_aux: }
-        \regex_build:n {#1}
-        \regex_match:n {#2}
-        \regex_extract_all_after_group:N #3
-      }
+    \exp_after:wN \regex_to_str_aux:Nw #1
+    \tex_toks:D \q_stop \prg_map_break: \tex_toks:D
+    \prg_break_point:n { }
   }
-\cs_new_protected:Npn \regex_extract_all:NnN #1#2#3
+\cs_new_nopar:Npn \regex_to_str_aux:Nw #1#2\tex_toks:D
   {
-    \regex_check_nfa:NT #1
-      {
-        \regex_user_aux:n
-          {
-            \seq_gclear:N \g_regex_extract_all_seq
-            \tl_set:Nn \l_regex_every_match_tl { \regex_extract_all_aux: }
-            \regex_use:N #1
-            \regex_match:n {#2}
-            \regex_extract_all_after_group:N #3
-          }
-      }
+    \use_none_delimit_by_q_stop:w #2 \q_stop
+    \tl_to_str:n {#1#2} \iow_newline:
+    \regex_to_str_aux:Nw \tex_toks:D
   }
-\cs_new_protected_nopar:Npn \regex_extract_all_aux:
+\cs_new_protected_nopar:Npn \regex_aux_return:
   {
-    \regex_extract:
-    \seq_gconcat:NNN \g_regex_extract_all_seq
-      \g_regex_extract_all_seq \g_regex_submatches_seq
-    \regex_match_once:
+    \if_meaning:w \c_true_bool \g_regex_success_bool
+      \prg_return_true:
+    \else:
+      \prg_return_false:
+    \fi:
   }
-\cs_new_protected_nopar:Npn \regex_extract_all_after_group:N #1
+\cs_new_protected:Npn \regex_aux_build_match:nn #1#2
   {
-    \seq_if_empty:NF \g_regex_extract_all_seq
-      {
-        \regex_extract:
-        \group_insert_after:N \seq_set_eq:NN
-        \group_insert_after:N #1
-        \group_insert_after:N \g_regex_extract_all_seq
-      }
+    \regex_build:n {#1}
+    \regex_match:n {#2}
   }
-\cs_new_protected:Npn \regex_split:nnN #1#2#3
+\cs_new_protected:Npn \regex_aux_use_match:Nn #1#2
   {
-    \regex_user_aux:n
+    \exp_args:No \tl_if_head_eq_meaning:nNTF {#1} \regex_nfa:Nw
       {
-        \seq_gclear:N \g_regex_split_seq
-        \tl_set:Nn \l_regex_every_match_tl { \regex_split_aux: }
-        \regex_build:n {#1}
+        \regex_use:N #1
         \regex_match:n {#2}
-        \regex_split_after_group:N #3
       }
-  }
-\cs_new_protected:Npn \regex_split:NnN #1#2#3
-  {
-    \regex_check_nfa:NT #1
-      {
-        \regex_user_aux:n
-          {
-            \seq_gclear:N \g_regex_split_seq
-            \tl_set:Nn \l_regex_every_match_tl { \regex_split_aux: }
-            \regex_use:N #1
-            \regex_match:n {#2}
-            \regex_split_after_group:N #3
-          }
-      }
-  }
-\cs_new_protected_nopar:Npn \regex_split_aux:
-  {
-    \int_compare:nNnF \l_regex_start_step_int = \l_regex_success_step_int
       {
-        \regex_extract:
-        \seq_pop:NN \g_regex_submatches_seq \l_regex_tmpa_tl
-        \regex_extract_aux:nTF {0}
-          {
-            \seq_gput_left:Nx \g_regex_submatches_seq
-              {
-                \regex_query_substr:NN
-                  \l_regex_start_step_int \l_regex_tmpa_tl
-              }
-          }
-          { \msg_error:nn { regex } { internal } }
-        \seq_gconcat:NNN \g_regex_split_seq
-          \g_regex_split_seq \g_regex_submatches_seq
+        \msg_kernel_error:nnx { regex } { not-nfa } { \token_to_str:N #1 }
+        \bool_gset_false:N \g_regex_success_bool
       }
-    \regex_match_once:
   }
-\cs_new_protected_nopar:Npn \regex_split_after_group:N #1
+\cs_set_protected:Npn \regex_tmp:w #1#2#3
   {
-    \int_compare:nNnTF \l_regex_start_step_int = \l_regex_current_step_int
+    \cs_new_protected_nopar:Npn #1
+      { #3 \regex_aux_build_match:nn }
+    \cs_new_protected_nopar:Npn #2
+      { #3 \regex_aux_use_match:Nn }
+    \prg_new_protected_conditional:Npnn #1 ##1##2##3 { T , F , TF }
       {
-        \bool_if:NF \l_regex_success_empty_bool
-          { \seq_gput_right:Nn \g_regex_split_seq { } }
+        #3 \regex_aux_build_match:nn {##1} {##2} ##3
+        \regex_aux_return:
       }
+    \prg_new_protected_conditional:Npnn #2 ##1##2##3 { T , F , TF }
       {
-        \seq_gput_right:Nx \g_regex_split_seq
-          {
-            \regex_query_substr:NN
-              \l_regex_start_step_int \l_regex_current_step_int
-          }
+        #3 \regex_aux_use_match:Nn {##1} {##2} ##3
+        \regex_aux_return:
       }
-    \group_insert_after:N \seq_set_eq:NN
-    \group_insert_after:N #1
-    \group_insert_after:N \g_regex_split_seq
   }
-\cs_new_protected:Npn \regex_replacement:n #1
+\tl_map_inline:nn
   {
-    \str_aux_escape:NNNn
-      \prg_do_nothing:
-      \regex_replacement_escaped:N
-      \prg_do_nothing:
-      {#1}
-    \tl_set_eq:NN \l_regex_replacement_tl \g_str_result_tl
-    \tl_set:Nx \l_regex_replacement_tl
-      { \l_regex_replacement_tl \prg_do_nothing: }
+    { extract_once } { extract_all }
+    { replace_once } { replace_all }
+    { split }
   }
-\cs_new_nopar:Npn \regex_replacement_escaped:N #1
   {
-    \regex_token_if_other_digit:NTF #1
-      {
-        \exp_not:n
-          { \exp_not:n { \seq_item:Nn \g_regex_submatches_seq } } {#1}
-      }
-      {
-        \token_if_eq_charcode:NNTF g #1
-          { \exp_not:N \regex_replacement_submatch:w }
-          { #1 }
-      }
+    \exp_args:Nccc \regex_tmp:w
+      { regex_#1:nnN } { regex_#1:NnN } { regex_#1_aux:NnnN }
   }
-\cs_new_nopar:Npn \regex_replacement_submatch:w #1
+\cs_new_protected_nopar:Npn \regex_extract:
   {
-    \exp_after:wN \token_if_eq_meaning:NNTF \c_lbrace_str #1
-      { \regex_replacement_submatch_aux:nN { } }
-      {
-        \regex_token_if_other_digit:NTF #1
-          { \exp_not:n { \seq_item:Nn \g_regex_submatches_seq } }
-          { \msg_expandable_kernel_error:nn { regex } { g-misused } }
-        #1
-      }
+    \int_set_eq:NN \l_regex_submatch_start_int \l_regex_submatch_int
+    \if_meaning:w \c_true_bool \g_regex_success_bool
+      \prg_replicate:nn \l_regex_capturing_group_int
+        {
+          \tex_skip:D \l_regex_submatch_int \c_zero sp \scan_stop:
+          \int_incr:N \l_regex_submatch_int
+        }
+      \prop_map_inline:Nn \l_regex_success_submatches_prop
+        {
+          \if_num:w ##1 \c_max_int
+            \exp_after:wN \regex_extract_aux_b:wn \int_use:N
+          \else:
+            \exp_after:wN \regex_extract_aux_e:wn \int_use:N
+          \fi:
+          \int_eval:w \l_regex_submatch_start_int + ##1 {##2}
+        }
+    \fi:
   }
-\cs_new_nopar:Npn \regex_replacement_submatch_aux:nN #1 #2
+\cs_new_protected_nopar:Npn \regex_extract_aux_b:wn #1 < #2
   {
-    \regex_token_if_other_digit:NTF #2
-      { \regex_replacement_submatch_aux:nN {#1#2} }
-      {
-        \exp_not:n { \seq_item:Nn \g_regex_submatches_seq } {#1}
-        \exp_after:wN \token_if_eq_meaning:NNF \c_rbrace_str #2
-          {
-            \msg_expandable_kernel_error:nn { regex } { g-misused }
-            #2
-          }
-      }
+    \tex_skip:D #1 = #2 sp
+      plus \etex_gluestretch:D \tex_skip:D #1 \scan_stop:
   }
-\cs_new_protected_nopar:Npn \regex_replace_after_group:N #1
+\cs_new_protected_nopar:Npn \regex_extract_aux_e:wn #1 > #2
   {
-    \group_insert_after:N \tl_set:Nx
-    \group_insert_after:N #1
-    \group_insert_after:N {
-      \group_insert_after:N \tl_to_str:N
-      \group_insert_after:N \g_regex_replaced_str
-    \group_insert_after:N }
+    \tex_skip:D #1
+      = 1 \tex_skip:D #1 plus #2 sp \scan_stop:
   }
-\cs_new_protected:Npn \regex_replace_once_aux:Nn #1#2
+\cs_new_protected:Npn \regex_group_end_extract_seq:N #1
   {
-    \group_begin:
-      \regex_replace_after_group:N #1
-      \tl_clear:N \l_regex_every_match_tl
-      #2
-      \exp_args:No \regex_match:n {#1}
-      \regex_extract:
-      \regex_extract_aux:nTF {0}
+      \cs_set_eq:NN \seq_item:n \scan_stop:
+      \flag_lower:N \l_regex_group_begin_flag
+      \flag_lower:N \l_regex_group_end_flag
+      \tl_set:Nx \l_regex_tmpa_tl
         {
-          \cs_set_nopar:Npn \regex_tmp:w
-            { \str_skip_do:nn { \l_regex_tmpb_tl } { } }
-          \tl_gset:Nx \g_regex_replaced_str
-            {
-              \regex_query_substr:NN \c_zero \l_regex_tmpa_tl
-              \l_regex_replacement_tl
-              \exp_after:wN \regex_tmp:w \l_regex_query_other_str
-            }
+          \prg_stepwise_function:nnnN
+            \l_regex_max_state_int
+            \c_one
+            { \l_regex_submatch_int - \c_one }
+            \regex_extract_seq_aux:n
         }
-        { \tl_gset_eq:NN \g_regex_replaced_str \l_regex_query_other_str }
-    \group_end:
+      \flag_test:NF \l_regex_group_begin_flag
+        { \flag_test:NF \l_regex_group_end_flag { \use_none:nnn } }
+      \msg_kernel_error:nn { regex } { sequence-unbalanced }
+      \tl_set:Nx \l_regex_tmpa_tl { \l_regex_tmpa_tl }
+    \exp_args:NNNo \group_end:
+    \tl_set:Nn #1 \l_regex_tmpa_tl
   }
-\cs_new_protected:Npn \regex_replace_once:nnN #1#2#3
+\cs_new_nopar:Npn \regex_extract_seq_aux:n #1
   {
-    \regex_replace_once_aux:Nn #3
+    \seq_item:n
       {
-        \regex_build:n {#1}
-        \regex_replacement:n {#2}
+        \exp_after:wN \regex_extract_seq_aux:ww
+        \int_value:w \regex_submatch_nesting_aux:n {#1} ; #1;
       }
   }
-\cs_new_protected:Npn \regex_replace_once:NnN #1#2#3
+\cs_new_nopar:Npn \regex_extract_seq_aux:ww #1; #2;
+  { %^^A todo: use flags
+    \if_num:w #1 < \c_zero
+      \flag_raise:N \l_regex_group_end_flag
+      \prg_replicate:nn {-#1} { \exp_not:n { { \if_false: } \fi: } }
+    \fi:
+    \regex_query_submatch:w #2;
+    \if_num:w #1 > \c_zero
+      \flag_raise:N \l_regex_group_begin_flag
+      \prg_replicate:nn {#1} { \exp_not:n { \if_false: { \fi: } } }
+    \fi:
+  }
+\prg_new_protected_conditional:Npnn \regex_match:nn #1#2 { T , F , TF }
   {
-    \regex_replace_once_aux:Nn #3
-      {
-        \regex_use:N #1
-        \regex_replacement:n {#2}
-      }
+    \regex_match_aux:n
+      { \regex_aux_build_match:nn {#1} {#2} }
   }
-\prg_new_protected_conditional:Npnn \regex_replace_once:nnN #1#2#3 {T,F,TF}
+\prg_new_protected_conditional:Npnn \regex_match:Nn #1#2 { T , F , TF }
   {
-    \regex_replace_once_aux:Nn #3
-      {
-        \regex_build:n {#1}
-        \regex_replacement:n {#2}
-        \regex_return_after_group:
-      }
+    \regex_match_aux:n
+      { \regex_aux_use_match:Nn #1 {#2} }
   }
-\prg_new_protected_conditional:Npnn \regex_replace_once:NnN #1#2#3 {T,F,TF}
+\cs_new_protected:Npn \regex_match_aux:n #1
   {
-    \regex_replace_once_aux:Nn #3
-      {
-        \regex_use:N #1
-        \regex_replacement:n {#2}
-        \regex_return_after_group:
-      }
+    \group_begin:
+      \tl_clear:N \l_regex_every_match_tl
+      \regex_disable_submatches:
+      #1
+    \group_end:
+    \regex_aux_return:
   }
-\cs_new_protected:Npn \regex_replace_all_aux:Nn #1#2
+\cs_new_protected_nopar:Npn \regex_count:nnN
+  { \regex_count_aux:NnnN \regex_aux_build_match:nn }
+\cs_new_protected_nopar:Npn \regex_count:NnN
+  { \regex_count_aux:NnnN \regex_aux_use_match:Nn }
+\cs_new_protected:Npn \regex_count_aux:NnnN #1#2#3#4
   {
     \group_begin:
-      \regex_replace_after_group:N #1
-      \tl_set:Nn \l_regex_every_match_tl { \regex_replace_all_aux: }
-      \tl_gclear:N \g_regex_replaced_str
-      #2
-      \exp_args:No \regex_match:n {#1}
-      \cs_set_nopar:Npn \regex_tmp:w
-        { \str_skip_do:nn { \l_regex_start_step_int } { } }
-      \tl_gput_right:Nx \g_regex_replaced_str
-        { \exp_after:wN \regex_tmp:w \l_regex_query_other_str }
+      \regex_disable_submatches:
+      \int_zero:N \l_regex_match_count_int
+      \tl_set:Nn \l_regex_every_match_tl
+        {
+          \int_incr:N \l_regex_match_count_int
+          \regex_match_once:
+        }
+      #1 {#2} {#3}
+      \exp_args:NNNo
     \group_end:
+    \int_set:Nn #4 { \int_use:N \l_regex_match_count_int }
   }
-\cs_new_protected_nopar:Npn \regex_replace_all_aux:
+\cs_new_protected:Npn \regex_extract_once_aux:NnnN #1#2#3#4
   {
-    \regex_extract:
-    \regex_extract_aux:nTF {0}
-      {
-        \tl_gput_right:Nx \g_regex_replaced_str
+    \group_begin:
+      \tl_set:Nn \l_regex_every_match_tl { \regex_extract: }
+      #1 {#2} {#3}
+      \regex_group_end_extract_seq:N #4
+  }
+\cs_new_protected:Npn \regex_extract_all_aux:NnnN #1#2#3#4
+  {
+    \group_begin:
+      \tl_set:Nn \l_regex_every_match_tl
+        { \regex_extract: \regex_match_once: }
+      #1 {#2} {#3}
+      \regex_group_end_extract_seq:N #4
+  }
+\cs_new_protected:Npn \regex_split_aux:NnnN #1#2#3#4
+  {
+    \group_begin:
+      \tl_set:Nn \l_regex_every_match_tl
+        {
+          \if_num:w \l_regex_start_step_int < \l_regex_success_step_int
+            \regex_extract:
+            \tex_skip:D \l_regex_submatch_start_int
+              = \l_regex_start_step_int sp
+                plus \tex_skip:D \l_regex_submatch_start_int \scan_stop:
+          \fi:
+          \regex_match_once:
+        }
+      #1 {#2} {#3}
+      \tex_skip:D \l_regex_submatch_int
+        = \l_regex_start_step_int sp
+          plus \l_regex_current_step_int sp \scan_stop:
+      \int_incr:N \l_regex_submatch_int
+      \if_num:w \l_regex_start_step_int = \l_regex_current_step_int
+        \if_meaning:w \c_true_bool \l_regex_success_empty_bool
+          \int_decr:N \l_regex_submatch_int
+        \fi:
+      \fi:
+      \regex_group_end_extract_seq:N #4
+  }
+\cs_new_protected:Npn \regex_replace_once_aux:NnnN #1#2#3#4
+  {
+    \group_begin:
+      \tl_clear:N \l_regex_every_match_tl
+      \regex_replacement:n {#3}
+      \exp_args:Nno #1 {#2} #4
+      \if_meaning:w \c_true_bool \g_regex_success_bool
+        \regex_extract:
+        \int_set:Nn \l_regex_tmpa_int
+          { \regex_nesting:n { \l_regex_submatch_start_int } }
+        \if_num:w \l_regex_tmpa_int = \c_zero
+        \else:
+          \msg_kernel_error:nnx { regex } { replace-unbalanced }
+            { \l_regex_tmpa_int }
+        \fi:
+        \tl_set:Nx \l_regex_tmpa_tl
           {
-            \regex_query_substr:NN
-              \l_regex_start_step_int \l_regex_tmpa_tl
-            \l_regex_replacement_tl
+            \if_num:w \l_regex_tmpa_int < \c_zero
+              \prg_replicate:nn { - \l_regex_tmpa_int }
+                { \exp_not:n { { \if_false: } \fi: } }
+            \fi:
+            \regex_query_substr:nn
+              { \l_regex_min_step_int }
+              { \tex_skip:D \l_regex_submatch_start_int }
+            \regex_replacement_tl:n { \l_regex_submatch_start_int }
+            \regex_query_substr:nn
+              { \etex_gluestretch:D \tex_skip:D \l_regex_submatch_start_int }
+              { \l_regex_max_step_int }
+            \if_num:w \l_regex_tmpa_int > \c_zero
+              \prg_replicate:nn { \l_regex_tmpa_int }
+                { \exp_not:n { \if_false: { \fi: } } }
+            \fi:
           }
-      }
-      { \msg_error:nn { regex } { internal } }
-    \regex_match_once:
+        \tl_set:Nx \l_regex_tmpa_tl { \l_regex_tmpa_tl }
+        \exp_args:NNNo \group_end:
+        \tl_set:Nn #4 \l_regex_tmpa_tl
+      \else:
+        \group_end:
+      \fi:
   }
-\cs_new_protected:Npn \regex_replace_all:nnN #1#2#3
+\cs_new_protected_nopar:Npn \regex_replace_once_aux:w #1;
   {
-    \regex_replace_all_aux:Nn #3
+  }
+\cs_new_protected:Npn \regex_replace_all_aux:NnnN #1#2#3#4
+  {
+    \group_begin:
+      \tl_set:Nn \l_regex_every_match_tl
+        {
+          \regex_extract:
+          \tex_skip:D \l_regex_submatch_start_int
+            = \tex_the:D \tex_skip:D \l_regex_submatch_start_int
+              minus \l_regex_start_step_int sp \scan_stop:
+          \regex_match_once:
+        }
+      \regex_replacement:n {#3}
+      \exp_args:Nno #1 {#2} #4
+      \int_set:Nn \l_regex_tmpa_int
+        {
+          0
+          \prg_stepwise_function:nnnN
+            \l_regex_max_state_int
+            \l_regex_capturing_group_int
+            { \l_regex_submatch_int - \c_one }
+            \regex_nesting:n
+        }
+      \if_num:w \l_regex_tmpa_int = \c_zero
+      \else:
+        \msg_kernel_error:nnx { regex } { replace-unbalanced }
+          { \l_regex_tmpa_int }
+      \fi:
+      \tl_set:Nx \l_regex_tmpa_tl
+        {
+          \if_num:w \l_regex_tmpa_int < \c_zero
+            \prg_replicate:nn { - \l_regex_tmpa_int }
+              { \exp_not:n { { \if_false: } \fi: } }
+          \fi:
+          \prg_stepwise_function:nnnN
+            \l_regex_max_state_int
+            \l_regex_capturing_group_int
+            { \l_regex_submatch_int - \c_one }
+            \regex_replace_all_aux:n
+          \regex_query_substr:nn
+            \l_regex_start_step_int \l_regex_max_step_int
+          \if_num:w \l_regex_tmpa_int > \c_zero
+            \prg_replicate:nn { \l_regex_tmpa_int }
+              { \exp_not:n { \if_false: { \fi: } } }
+          \fi:
+        }
+      \tl_set:Nx \l_regex_tmpa_tl { \l_regex_tmpa_tl }
+    \exp_args:NNNo \group_end:
+    \tl_set:Nn #4 \l_regex_tmpa_tl
+  }
+\cs_new_nopar:Npn \regex_replace_all_aux:n #1
+  {
+    \regex_query_substr:nn
+      { \etex_glueshrink:D \tex_skip:D #1 } { \tex_skip:D #1 }
+    \regex_replacement_tl:n {#1}
+  }
+\msg_kernel_new:nnnn { regex } { sequence-unbalanced }
+  {
+    Missing~
+    \flag_test:NTF \l_regex_group_end_flag
       {
-        \regex_build:n {#1}
-        \regex_replacement:n {#2}
+        left~
+        \flag_test:NTF \l_regex_group_begin_flag
+          { and~right~braces } { brace }
       }
+      { right~brace }
+    \ inserted~in~extracted~match.
   }
-\cs_new_protected:Npn \regex_replace_all:NnN #1#2#3
   {
-    \regex_replace_all_aux:Nn #3
+    LaTeX~was~asked~to~extract~submatches~or~split~a~token~list~
+    according~to~a~given~regular~expression,~but~some~of~the~resulting~
+    items~were~not~balanced.
+  }
+\msg_kernel_new:nnnn { regex } { replace-unbalanced }
+  { The~result~of~a~replacement~does~not~have~balanced~braces. }
+  {
+    LaTeX~was~asked~to~do~some~regular~expression~replacement,~
+    and~the~resulting~token~list~would~not~have~the~same~number~
+    of~begin-group~and~end-group~tokens. \\ \\
+    \ \ \ \
+    \prg_case_int:nnn {#1}
       {
-        \regex_use:N #1
-        \regex_replacement:n {#2}
+        { -1 } { A~left~brace~was }
+        {  1 } { A~right~brace~was }
       }
+      {
+        \int_abs:n {#1} ~
+        \int_compare:nNnTF {#1} < \c_zero { left } { right } ~
+        braces ~ were
+      }
+    \ inserted.
+  }
+\msg_kernel_new:nnnn { regex } { missing-rparen }
+  { Missing~right~parenthesis~added~in~regular~expression. }
+  {
+    LaTeX~was~given~a~regular~expression~with~\int_eval:n{#1}~
+    more~left~parenthes\int_compare:nTF{#1=1}{i}{e}s~than~right~
+    parenthes\int_compare:nTF{#1=1}{i}{e}s.
+  }
+\msg_kernel_new:nnnn { regex } { extra-rparen }
+  { Extra~right~parenthesis~ignored~in~regular~expression. }
+  {
+    LaTeX~came~across~a~closing~parenthesis~when~no~submatch~group~
+    was~open.~The~parenthesis~will~be~ignored.
   }
-\msg_new:nnn { regex } { -998 } { Unsupported~construct }
-\msg_new:nnn { regex } { -997 }
-  { The~regular~expression~is~too~large~(32768~states). }
-\msg_new:nnn { regex } { 1 } { \iow_char:N\\~at~end~of~pattern }
-\msg_new:nnn { regex } { 4 }
-  { Numbers~out~of~order~in~\iow_char:N\{\iow_char\}~quantifier. }
-\msg_new:nnn { regex } { 6 }
-  { Missing~terminating~\iow_char:N\]~for~character~class }
-\msg_new:nnn { regex } { 7 }
-  { Invalid~escape~sequence~in~character~class }
-\msg_new:nnn { regex } { 8 }
-  { Range~out~of~order~in~character~class }
-\msg_new:nnn { regex } { 22 } { Mismatched~parentheses }
-\msg_new:nnn { regex } { 34 }
-  { Character~value~in~\iow_char:N\\x{...}~sequence~is~too~large }
-\msg_new:nnn { regex } { not-nfa }
-  {
-    LaTeX~was~expecting~a~regular~expression~variable.\\
-    Instead,~LaTeX~found~'#1'.
+\msg_kernel_new:nnnn { regex } { backwards-range }
+  { Range~[#1-#2]~out~of~order~in~character~class. }
+  {
+    In~ranges~of~characters~[x-y]~appearing~in~character~classes,~
+    the~first~character~code~must~not~be~larger~than~the~second.~
+    Here,~#1~has~character~code~\int_eval:n {`#1},~while~#2~has~
+    character~code~\int_eval:n {`#2}.
+  }
+\msg_kernel_new:nnnn { regex } { unsupported }
+  { Unsupported~construction~`#1'. }
+  {
+    The~construction~`#1'~is~not~supported~by~the~LaTeX~
+    regular~expression~module.~Perhaps~some~character~should~
+    have~been~escaped?
+  }
+\msg_kernel_new:nnnn { regex } { not-nfa }
+  { This~is~not~a~regular~expression~variable. }
+  {
+    LaTeX~was~expecting~`#1'~to~be~a~regular~expression~variable.\\
+    This~control~sequence~is~not~a~regex~variable.~It's~current~meaning~
+    is~\\\\
+    \ \ \ \ \token_to_str:N #1 = \token_to_meaning:N #1 .
+  }
+\msg_kernel_new:nnnn { regex } { build-c }
+  { Misused~\iow_char:N\\c~or\iow_char:N\\C~command~in~regular~expression. }
+  {
+    The~\iow_char:N\\C~escape~sequence~can~be~followed~by~
+    one~of~the~letters~ABCDELMOPSTU.~The~\iow_char:N\\c~
+    escape~sequence~can~also~be~followed~by~a~brace~group.
+  }
+\msg_kernel_new:nnnn { regex } { unknown-option }
+  { Unknown~option~`#1'~for~regular~expressions. }
+  {
+    LaTeX~came~across~something~like~`(?#1)'~in~a~regular~expression,~
+    but~the~option~`#1'~is~not~known.~It~will~be~ignored.
+  }
+\msg_kernel_new:nnnn { regex } { invalid-in-option }
+  { Invalid~character~in~option~of~a~regular~expression. }
+  {
+    The~character~or~escape~sequence~`#1'~is~not~defined~
+    as~an~option~within~regular~expressions.
+  }
+\msg_kernel_new:nnnn { regex } { replacement-g }
+  { Missing~brace~for~the~\iow_char:N\\g~construction~in~a~replacement~text. }
+  {
+    In~the~replacement~text~for~a~regular~expression~search,~
+    submatches~are~represented~either~as~\iow_char:N \\g{dd..d},~
+    or~\\d,~where~`d'~are~single~digits.~Here,~a~brace~is~missing.
+  }
+\msg_kernel_new:nnnn { regex } { replacement-c }
+  { Something~is~wrong~with~the~replacement~text. }
+  {
+    The~\iow_char:N\\c~escape~sequence~can~only~be~followed~by~
+    ABCDELMN~or~by~a~brace.
   }
 \msg_kernel_new:nnn { regex } { nfa-misused }
   { Automaton~#1 used~incorrectly. }
-\msg_kernel_new:nnn { regex } { g-misused }
-  { \g misused~in~replacement~text. }
 %% 
 %%
 %% End of file `l3regex.sty'.
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-hex.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-hex.def
index 9af2e4322ad..b24f29458a5 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-hex.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-hex.def
@@ -47,13 +47,16 @@
 %% -----------------------------------------------------------------------
 \cs_new_protected_nopar:Npn \str_convert_input_hex:
   {
-    \tl_gset:Nx \g_str_result_tl
-      {
-        \str_output_byte:w "
-          \exp_after:wN \str_convert_input_hex_aux:N
-          \g_str_result_tl 0 { ? 0 - \c_one \prg_map_break: }
-        \prg_break_point:n { \str_output_end: }
-      }
+    \group_begin:
+      \int_set:Nn \tex_escapechar:D { 92 }
+      \tl_gset:Nx \g_str_result_tl
+        {
+          \str_output_byte:w "
+            \exp_after:wN \str_convert_input_hex_aux:N
+            \g_str_result_tl 0 { ? 0 - \c_one \prg_map_break: }
+          \prg_break_point:n { \str_output_end: }
+        }
+    \group_end:
   }
 \cs_new_nopar:Npn \str_convert_input_hex_aux:N #1
   {
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-name.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-name.def
index 8d378c87e3d..66e7dddb6b8 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-name.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-name.def
@@ -49,12 +49,15 @@
   {
     \cs_new_protected_nopar:Npn #2
       {
-        \tl_gset:Nx \g_str_result_tl
-          {
-            \exp_after:wN #3 \g_str_result_tl
-              #1 ? { ? \prg_map_break: }
-            \prg_break_point:n { }
-          }
+        \group_begin:
+          \int_set:Nn \tex_escapechar:D { 92 }
+          \tl_gset:Nx \g_str_result_tl
+            {
+              \exp_after:wN #3 \g_str_result_tl
+                #1 ? { ? \prg_map_break: }
+              \prg_break_point:n { }
+            }
+        \group_end:
       }
     \cs_new_nopar:Npn #3 ##1#1##2##3
       {
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-string.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-string.def
index 7718a0d1b25..5e8fd099b25 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-string.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-string.def
@@ -53,18 +53,21 @@
     {
       \cs_new_protected_nopar:Npn \str_convert_input_string:
         {
-          \tl_gset:Nx \g_str_result_tl
-            {
-              \exp_after:wN \str_convert_input_string_aux:wN
-                \g_str_result_tl \prg_map_break: ^^M ?
-              \prg_break_point:n { }
-            }
-          \tl_gset:Nx \g_str_result_tl
-            {
-              \exp_after:wN \str_convert_input_string_aux:wNNN
-                \g_str_result_tl * ?? { ? \prg_map_break: }
-              \prg_break_point:n { }
-            }
+          \group_begin:
+            \int_set:Nn \tex_escapechar:D { 92 }
+            \tl_gset:Nx \g_str_result_tl
+              {
+                \exp_after:wN \str_convert_input_string_aux:wN
+                  \g_str_result_tl \prg_map_break: ^^M ?
+                \prg_break_point:n { }
+              }
+            \tl_gset:Nx \g_str_result_tl
+              {
+                \exp_after:wN \str_convert_input_string_aux:wNNN
+                  \g_str_result_tl * ?? { ? \prg_map_break: }
+                \prg_break_point:n { }
+              }
+          \group_end:
         }
       \cs_new_nopar:Npn \str_convert_input_string_aux:wNNN #1 *#2#3#4
     }
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-url.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-url.def
index bf6bf96514d..13cbde871fe 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-url.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-url.def
@@ -49,12 +49,15 @@
   {
     \cs_new_protected_nopar:Npn #2
       {
-        \tl_gset:Nx \g_str_result_tl
-          {
-            \exp_after:wN #3 \g_str_result_tl
-              #1 ? { ? \prg_map_break: }
-            \prg_break_point:n { }
-          }
+        \group_begin:
+          \int_set:Nn \tex_escapechar:D { 92 }
+          \tl_gset:Nx \g_str_result_tl
+            {
+              \exp_after:wN #3 \g_str_result_tl
+                #1 ? { ? \prg_map_break: }
+              \prg_break_point:n { }
+            }
+        \group_end:
       }
     \cs_new_nopar:Npn #3 ##1#1##2##3
       {
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf16.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf16.def
index e2bea7ca224..001b955ac07 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf16.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf16.def
@@ -127,13 +127,13 @@
       \if_meaning:w \scan_stop: #2
         \str_aux_from_utf_xvi_end:Nw #1
       \fi:
-      \int_use:N \int_eval:w
-        \if_case:w
-          \int_eval:w ( \str_tmp:w #1#2 - "D6 ) / \c_four \int_eval_end:
-        \or: \exp_after:wN \str_aux_from_utf_xvi:wNNN
-        \or: \exp_after:wN \str_aux_from_utf_xvi_error:wNNw
-        \fi:
-        "100 * \str_tmp:w #1#2 + \str_tmp:w #2#1 ,
+      \if_case:w
+        \int_eval:w ( \str_tmp:w #1#2 - "D6 ) / \c_four \int_eval_end:
+      \or: #1#2 \exp_after:wN \str_aux_from_utf_xvi:wNNN
+      \or: \exp_after:wN \str_aux_from_utf_xvi_error:wNNw
+      \else: #1#2 \exp_not:N \q_mark \int_use:N \int_eval:w
+      \fi:
+      "100 * \str_tmp:w #1#2 + \str_tmp:w #2#1 ,
       \str_aux_from_utf_xvi:NN
     }
   \cs_new:Npn \str_aux_from_utf_xvi:wNNN #1, #2#3#4
@@ -142,8 +142,10 @@
         \str_aux_from_utf_xvi_end:wNNww #1 , #3
       \fi:
       \if_num:w \int_eval:w ( \str_tmp:w #3#4 - "DA ) / \c_four = \c_one
-        ( #1 - "D800 ) * "400
-          + \str_tmp:w #3#4 * "100 + \str_tmp:w #4#3 - "DC00 ,
+        #3 #4
+        \int_use:N \int_eval:w
+          ( #1 - "D800 ) * "400
+            + \str_tmp:w #3#4 * "100 + \str_tmp:w #4#3 - "DC00 ,
         \exp_after:wN \use_i:nnn
       \else:
         \str_aux_from_utf_xvi_error:wNNw #1 ,
@@ -152,6 +154,7 @@
     }
   \cs_new:Npn \str_aux_from_utf_xvi_error:wNNw #1 \str_tmp:w #2#3 #4,
     {
+      \exp_not:N \q_mark
       \msg_expandable_kernel_error:nnn
         { str } { utf16-surrogate } { #2#3 }
       \c_str_replacement_char_int ,
@@ -161,15 +164,17 @@
       \fi:
       \if_meaning:w \scan_stop: #1
       \else:
+        #1 \exp_not:N \q_mark
         \msg_expandable_kernel_error:nnn
           { str } { utf16-odd } {#1}
-        \c_str_replacement_char_int ,
+        \int_use:N \c_str_replacement_char_int ,
       \fi:
       \prg_map_break:
     }
   \cs_new:Npn \str_aux_from_utf_xvi_end:wNNww #1 `#2#3 #4, #5 \fi:
     {
       \fi:
+      \exp_not:N \q_mark
       \if_meaning:w \scan_stop: #5
         \msg_expandable_kernel_error:nnn
           { str } { utf16-surrogate } { #2#3 }
@@ -177,7 +182,7 @@
         \msg_expandable_kernel_error:nnn
           { str } { utf16-odd } { #2#3#5 }
       \fi:
-      \c_str_replacement_char_int ,
+      \int_use:N \c_str_replacement_char_int ,
       \prg_map_break:
     }
 \group_end:
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf32.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf32.def
index 7c56d2e3929..8251d8c44fe 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf32.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf32.def
@@ -107,31 +107,33 @@
   \cs_new:Npn \str_aux_from_utf_xxxii:NNNN #1#2#3#4
     {
       \if_meaning:w \scan_stop: #4
-        \str_aux_from_utf_xxxii_end:ww #1#2#3#4
+        \exp_after:wN \str_aux_from_utf_xxxii_end:w
+      \fi:
+      #1#2#3#4 \exp_not:N \q_mark
+      \if_num:w \int_eval:w
+                  \str_tmp:w #1#4 * \c_two_hundred_fifty_six
+                  + \str_tmp:w #2#3
+                > \c_sixteen
+        \msg_expandable_kernel_error:nnn
+          { str } { utf32-overflow } { #1#2#3#4 }
+        \int_use:N \c_str_replacement_char_int
+      \else:
+        \int_use:N \int_eval:w
+        \str_tmp:w #2#3*"10000
+        + \str_tmp:w #3#2 * \c_two_hundred_fifty_six
+        + \str_tmp:w #4#1
       \fi:
-      \int_use:N \int_eval:w
-        \if_num:w \int_eval:w
-                    \str_tmp:w #1#4 * \c_two_hundred_fifty_six
-                    + \str_tmp:w #2#3
-                  > \c_sixteen
-          \msg_expandable_kernel_error:nnn
-            { str } { utf32-overflow } { #1#2#3#4 }
-          \c_str_replacement_char_int
-        \else:
-          \str_tmp:w #2#3*"10000
-          + \str_tmp:w #3#2 * \c_two_hundred_fifty_six
-          + \str_tmp:w #4#1
-        \fi:
       ,
       \str_aux_from_utf_xxxii:NNNN
     }
-  \cs_new:Npn \str_aux_from_utf_xxxii_end:ww #1 \scan_stop: #2 \fi:
+  \cs_new:Npn \str_aux_from_utf_xxxii_end:w #1 \scan_stop:
     {
-      \fi:
       \tl_if_empty:nF {#1}
         {
           \msg_expandable_kernel_error:nnn
             { str } { utf32-truncated } { #1 }
+          #1 \exp_not:N \q_mark
+          \int_use:N \c_str_replacement_char_int ,
         }
       \prg_map_break:
     }
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf8.def b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf8.def
index 9e0f26c2346..d6233f22557 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf8.def
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str-utf8.def
@@ -74,32 +74,33 @@
     \tl_gset:Nx \g_str_result_tl
       {
         \exp_after:wN \str_aux_from_utf_viii:N \g_str_result_tl
-          { ? \prg_map_break: \q_stop \str_aux_from_utf_viii_error: }
+          { \prg_map_break: \str_aux_from_utf_viii_error: }
         \prg_break_point:n { }
       }
   }
 \cs_new_nopar:Npn \str_aux_from_utf_viii:N #1
   {
-    \use_none:n #1
-    \int_use:N \int_eval:w
-      \if_num:w `#1 < "C0 \exp_stop_f:
-        \if_num:w `#1 < "80 \exp_stop_f:
-          `#1
-        \else:
-          \msg_expandable_kernel_error:nnn
-            { str } { utf8-extra-conti } {#1}
-          \c_str_replacement_char_int
-        \fi:
+    #1
+    \if_num:w `#1 < "C0 \exp_stop_f:
+      \exp_not:N \q_mark
+      \if_num:w `#1 < "80 \exp_stop_f:
+        \int_value:w `#1
       \else:
-        \if_num:w `#1 < "F5 \exp_stop_f:
-          \exp_after:wN \str_aux_from_utf_viii:wwNN
-            \int_use:N \int_eval:w `#1 - "C0
-        \else:
-          \msg_expandable_kernel_error:nnn
-            { str } { utf8-invalid-byte } {#1}
-          \c_str_replacement_char_int
-        \fi:
+        \msg_expandable_kernel_error:nnn
+          { str } { utf8-extra-conti } {#1}
+        \int_use:N \c_str_replacement_char_int
       \fi:
+    \else:
+      \if_num:w `#1 < "F5 \exp_stop_f:
+        \exp_after:wN \str_aux_from_utf_viii:wwNN
+          \int_use:N \int_eval:w `#1 - "C0
+      \else:
+        \exp_not:N \q_mark
+        \msg_expandable_kernel_error:nnn
+          { str } { utf8-invalid-byte } {#1}
+        \int_use:N \c_str_replacement_char_int
+      \fi:
+    \fi:
     ,
     \use_none_delimit_by_q_stop:w
       "80 , "800 , "10000 , "10FFFF ,
@@ -108,7 +109,7 @@
   }
 \cs_new_nopar:Npn \str_aux_from_utf_viii:wwNN #1 , #2 \q_stop #3#4
   {
-    \use_none_delimit_by_q_stop:w #4 \q_stop
+    \use_none:n #4
     \exp_after:wN \str_aux_from_utf_viii:wNNww
       \int_use:N \int_eval:w #1 * "40 + `#4 - "80 ,
       #4
@@ -121,8 +122,9 @@
       \if_num:w #1 < #4 \exp_stop_f:
         \str_aux_from_utf_viii_error:w #1 ,
       \else:
+        #2
         \if_num:w #1 < #5 \exp_stop_f:
-          #1
+          \exp_not:N \q_mark #1
         \else:
           \exp_after:wN \str_aux_from_utf_viii:wwNN
             \int_use:N \int_eval:w #1 - #5
@@ -136,12 +138,14 @@
   }
 \cs_new_nopar:Npn \str_aux_from_utf_viii_error:w #1 ,
   {
+    \exp_not:N \q_mark
     \msg_expandable_kernel_error:nnn
       { str } { utf8-overlong } {#1}
     \c_str_replacement_char_int
   }
 \cs_new_nopar:Npn \str_aux_from_utf_viii_error:NwN #1 #2 \q_stop #3
   {
+    \exp_not:N \q_mark
     \msg_expandable_kernel_error:nnn
       { str } { utf8-missing-conti } {#1}
     \c_str_replacement_char_int ,
@@ -149,6 +153,7 @@
   }
 \cs_new_nopar:Npn \str_aux_from_utf_viii_error:
   {
+    \exp_not:N \q_mark
     \msg_expandable_kernel_error:nn
       { str } { utf8-premature-end }
     \c_str_replacement_char_int ,
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str.sty b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str.sty
index c49601841e0..7d527b6d264 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str.sty
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3str.sty
@@ -46,23 +46,10 @@
 %%
 %% -----------------------------------------------------------------------
 \RequirePackage{expl3}
-\GetIdInfo$Id: l3str.dtx 3035 2011-12-07 11:48:46Z bruno $
+\GetIdInfo$Id: l3str.dtx 3088 2011-12-23 02:00:14Z bruno $
   {L3 Experimental Strings}
 \ProvidesExplPackage
   {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription}
-\cs_if_exist:NF \use_i:nnnnnnnn
-  { \cs_new:Npn \use_i:nnnnnnnn #1#2#3#4#5#6#7#8 {#1} }
-\int_const:Nn \c_forty_eight  { 48 }
-\int_const:Nn \c_fifty_eight  { 58 }
-\int_const:Nn \c_sixty_five   { 65 }
-\int_const:Nn \c_ninety_one   { 91 }
-\int_const:Nn \c_ninety_seven { 97 }
-\int_const:Nn \c_one_hundred_twenty_three { 123 }
-\int_const:Nn \c_one_hundred_twenty_seven { 127 }
-\pdftex_if_engine:TF
-  { \int_const:Nn \c_max_char_int { 255 } }
-  { \int_const:Nn \c_max_char_int { 1114111 } }
-\int_const:Nn \c_str_replacement_char_int { "FFFD }
 \group_begin:
   \cs_set_protected_nopar:Npn \str_tmp:w #1
     {
@@ -80,8 +67,19 @@
 \group_end:
 \cs_new_protected_nopar:Npn \str_tmp:w { }
 \tl_new:N \l_str_tmpa_tl
+\int_new:N \l_str_tmpa_int
 \tl_new:N \g_str_result_tl
 \int_new:N \l_str_char_int
+\int_const:Nn \c_forty_eight  { 48 }
+\int_const:Nn \c_fifty_eight  { 58 }
+\int_const:Nn \c_sixty_five   { 65 }
+\int_const:Nn \c_ninety_one   { 91 }
+\int_const:Nn \c_ninety_seven { 97 }
+\int_const:Nn \c_one_hundred_twenty_three { 123 }
+\int_const:Nn \c_one_hundred_twenty_seven { 127 }
+\int_const:Nn \c_max_char_int
+  { \pdftex_if_engine:TF { 255 } { 1114111 } }
+\int_const:Nn \c_str_replacement_char_int { "FFFD }
 \tl_const:Nx \c_backslash_str { \cs_to_str:N \\ }
 \tl_const:Nx \c_lbrace_str    { \cs_to_str:N \{ }
 \tl_const:Nx \c_rbrace_str    { \cs_to_str:N \} }
@@ -100,7 +98,6 @@
 \prop_gput:Nnn \g_str_aliases_prop { latin9 } { iso885915 }
 \prop_gput:Nnn \g_str_aliases_prop { latin10 } { iso885916 }
 \prop_gput:Nnn \g_str_aliases_prop { hexadecimal } { hex }
-\prop_gput:Nnn \g_str_aliases_prop { percent } { url }
 \group_begin:
 \char_set_lccode:nn { `\* } { `\  }
 \char_set_lccode:nn { `\A } { `\A }
@@ -124,72 +121,53 @@
     \cs_new_nopar:Npn \tl_to_other_str_end:w \fi: #1 \q_mark #2 * A #3 \q_stop
       { \fi: #2 }
   }
-\cs_new_nopar:Npn \tl_to_other_str:N { \exp_args:No \tl_to_other_str:n }
-\cs_new:Npn \str_sanitize_args:Nn #1#2
-  { \exp_args:Nf #1 { \tl_to_other_str:n {#2} } }
-\cs_new:Npn \str_sanitize_args:Nnn #1#2#3
-  {
-    \exp_args:Nff #1
-      { \tl_to_other_str:n {#2} }
-      { \tl_to_other_str:n {#3} }
-  }
 \group_begin:
 \char_set_lccode:nn { `\* } { `\  }
 \char_set_lccode:nn { `\A } { `\A }
 \tl_to_lowercase:n
   {
     \group_end:
-    \cs_new_protected:Npn \str_aux_gset_other:Nn #1#2
+    \cs_new_protected:Npn \str_gset_other:Nn #1#2
       {
         \tl_gset:Nx #1
           {
-            \exp_after:wN \str_aux_gset_other_loop:w \tl_to_str:n {#2} ~ %
+            \exp_after:wN \str_gset_other_loop:w \tl_to_str:n {#2} ~ %
             A ~ A ~ A ~ A ~ A ~ A ~ A ~ A ~ A ~ \q_mark \q_stop
           }
       }
-    \cs_new_nopar:Npn \str_aux_gset_other_loop:w
+    \cs_new_nopar:Npn \str_gset_other_loop:w
       #1 ~ #2 ~ #3 ~ #4 ~ #5 ~ #6 ~ #7 ~ #8 ~ #9 ~
       {
         \if_meaning:w A #9
-          \str_aux_gset_other_end:w
+          \str_gset_other_end:w
         \fi:
         #1 * #2 * #3 * #4 * #5 * #6 * #7 * #8 * #9
-        \str_aux_gset_other_loop:w *
+        \str_gset_other_loop:w *
       }
-    \cs_new_nopar:Npn \str_aux_gset_other_end:w \fi: #1 * A #2 \q_stop
+    \cs_new_nopar:Npn \str_gset_other_end:w \fi: #1 * A #2 \q_stop
       { \fi: #1 }
   }
-\cs_new_nopar:Npn \str_map_tokens:Nn
-  { \exp_args:No \str_map_tokens:nn }
-\cs_new:Npn \str_map_tokens:nn #1
-  { \exp_args:No \str_map_tokens_aux:nn { \tl_to_str:n {#1} } }
-\cs_new:Npn \str_map_tokens_aux:nn #1#2
+\cs_if_exist:NF \use_i:nnnnnnnn
+  { \cs_new:Npn \use_i:nnnnnnnn #1#2#3#4#5#6#7#8 {#1} }
+\cs_new:Npn \str_aux_toks_range:nn #1#2
   {
-    \str_map_tokens_loop:nw {#2} #1
-      { ? \use_none_delimit_by_q_recursion_stop:w }
-      ?~ ?~ ?~ ?~ ?~ ?~ ?~ ?~ \q_recursion_stop
+    \exp_after:wN \str_aux_toks_range:ww
+    \int_use:N \int_eval:w #1 \exp_after:wN ;
+    \int_use:N \int_eval:w #2 ;
+    \prg_break_point:n { }
   }
-\group_begin:
-  \char_set_lccode:nn { `* } { `\ }
-  \tl_to_lowercase:n
-    {
-      \group_end:
-      \cs_new:Npn \str_map_tokens_loop:nw #1 #2~ #3~ #4~ #5~ #6~ #7~ #8~ #9~
-        {
-          \str_map_tokens_loop:nN {#1} #2* #3* #4* #5* #6* #7* #8* #9*
-            { ? \use_none_delimit_by_q_stop:w } \q_stop
-          \str_map_tokens_loop:nw {#1}
-        }
-    }
-\cs_new:Npn \str_map_tokens_loop:nN #1#2
+\cs_new:Npn \str_aux_toks_range:ww #1 ; #2 ;
   {
-    \use_none:n #2
-    #1 #2
-    \str_map_tokens_loop:nN {#1}
+    \if_num:w #1 = #2 \exp_stop_f:
+      \exp_after:wN \prg_map_break:
+    \fi:
+    \tex_the:D \tex_toks:D #1 \exp_stop_f:
+    \exp_after:wN \str_aux_toks_range:ww
+      \int_use:N \int_eval:w #1 + \c_one ; #2 ;
   }
-\cs_new_eq:NN \str_map_break_do:n \use_i_delimit_by_q_recursion_stop:nw
 \cs_new_nopar:Npn \str_length:N { \exp_args:No \str_length:n }
-\cs_new:Npn \str_length:n { \str_sanitize_args:Nn \str_length_unsafe:n }
+\cs_new:Npn \str_length:n #1
+  { \exp_args:Nf \str_length_unsafe:n { \tl_to_other_str:n {#1} } }
 \cs_new_nopar:Npn \str_length_unsafe:n #1
   { \str_length_aux:n { \str_length_loop:NNNNNNNNN #1 } }
 \cs_new:Npn \str_length_ignore_spaces:n #1
@@ -308,7 +286,7 @@
 \cs_new:Npn \str_item:nn #1#2
   {
     \exp_args:Nf \tl_to_str:n
-      { \str_sanitize_args:Nn \str_item_unsafe:nn {#1} {#2} }
+      { \exp_args:Nf \str_item_unsafe:nn { \tl_to_other_str:n {#1} } {#2} }
   }
 \cs_new:Npn \str_item_ignore_spaces:nn #1
   { \exp_args:No \str_item_unsafe:nn { \tl_to_str:n {#1} } }
@@ -344,26 +322,31 @@
 \cs_new:Npn \str_substr:nnn #1#2#3
   {
     \exp_args:Nf \tl_to_str:n
-      { \str_sanitize_args:Nn \str_substr_unsafe:nnn {#1} {#2} {#3} }
+      {
+        \exp_args:Nf \str_substr_unsafe:nnn
+          { \tl_to_other_str:n {#1} } {#2} {#3}
+      }
   }
 \cs_new:Npn \str_substr_ignore_spaces:nnn #1
   { \exp_args:No \str_substr_unsafe:nnn { \tl_to_str:n {#1} } }
 \cs_new:Npn \str_substr_unsafe:nnn #1#2#3
   {
-    \str_aux_eval_args:Nnnn \str_substr_aux:nnnw
-      { \str_length_unsafe:n {#1} }
-      {#2}
-      {#3}
+    \exp_after:wN \str_substr_aux:www
+    \int_value:w \str_length_unsafe:n {#1} \exp_after:wN ;
+    \int_use:N \int_eval:w #2 + \c_zero \exp_after:wN ;
+    \int_use:N \int_eval:w \exp_args:Nf \str_substr_unsafe:nN {#3} \c_max_int ;
       #1
     \q_stop
   }
-\cs_new:Npn \str_substr_aux:nnnw #1#2#3
+\cs_new:Npn \str_substr_unsafe:nN #1 #2
+  { \tl_if_empty:nTF {#1} {#2} {#1} }
+\cs_new:Npn \str_substr_aux:www #1; #2; #3;
   {
-    \exp_args:Nf \str_substr_aux_ii:nnw
+    \exp_args:Nf \str_substr_aux:nnw
       { \str_aux_normalize_range:nn {#2} {#1} }
       { \str_aux_normalize_range:nn {#3} {#1} }
   }
-\cs_new:Npn \str_substr_aux_ii:nnw #1#2
+\cs_new:Npn \str_substr_aux:nnw #1#2
   {
     \str_skip_do:nn {#1}
       {
@@ -372,13 +355,6 @@
           { \use_i_delimit_by_q_stop:nw }
       }
   }
-\cs_new:Npn \str_aux_eval_args:Nnnn #1#2#3#4
-  {
-    \exp_after:wN #1
-    \exp_after:wN { \int_value:w \int_eval:w #2 \exp_after:wN }
-    \exp_after:wN { \int_value:w \int_eval:w #3 \exp_after:wN }
-    \exp_after:wN { \int_value:w \int_eval:w #4 }
-  }
 \cs_new:Npn \str_aux_normalize_range:nn #1#2
   {
     \int_eval:n
@@ -403,69 +379,32 @@
     \if_int_compare:w \pdftex_strcmp:D { \tl_to_str:N #1 } { \tl_to_str:N #2 }
       = \c_zero \prg_return_true: \else: \prg_return_false: \fi:
   }
-\prg_new_conditional:Npnn \str_if_contains_char:NN #1#2 { p , T , F , TF }
+\prg_new_conditional:Npnn \str_if_contains_char:NN #1#2 { T , TF }
   {
-    \str_map_tokens:Nn #1 { \str_if_contains_char_aux:NN #2 }
+    \exp_after:wN \str_if_contains_char_aux:NN \exp_after:wN #2
+      #1 { \prg_map_break:n { ? \fi: } }
+    \prg_break_point:n { }
     \prg_return_false:
   }
-\prg_new_conditional:Npnn \str_if_contains_char:nN #1#2 { p , T , F , TF }
+\prg_new_conditional:Npnn \str_if_contains_char:nN #1#2 { TF }
   {
-    \str_map_tokens:nn {#1} { \str_if_contains_char_aux:NN #2 }
+    \exp_after:wN \str_if_contains_char_aux:NN \exp_after:wN #2
+      \tl_to_str:n {#1} { \prg_map_break:n { ? \fi: } }
+    \prg_break_point:n { }
     \prg_return_false:
   }
 \cs_new_nopar:Npn \str_if_contains_char_aux:NN #1#2
   {
-    \if_num:w `#1 = `#2 \exp_stop_f:
-      \str_if_contains_char_end:w
+    \if_charcode:w #1 #2
+      \exp_after:wN \str_if_contains_char_end:
     \fi:
+    \str_if_contains_char_aux:NN #1
   }
-\cs_new_nopar:Npn \str_if_contains_char_end:w \fi: #1 \prg_return_false:
-  { \fi: \prg_return_true: }
-\pdftex_if_engine:TF
-  {
-    \cs_new_eq:NN \str_if_bytes_p:N \c_true_bool
-    \cs_new_eq:NN \str_if_bytes:NT  \use_ii:nn
-    \cs_new_eq:NN \str_if_bytes:NF  \use_none:nn
-    \cs_new_eq:NN \str_if_bytes:NTF \use_ii:nnn
-  }
-  {
-    \prg_new_conditional:Npnn \str_if_bytes:N #1 { p , T , F , TF }
-      {
-        \exp_args:Nf \tl_map_function:nN
-          { \tl_to_str:N #1 }
-          \str_if_bytes_aux:N
-        \prg_return_true:
-      }
-    \cs_new_nopar:Npn \str_if_bytes_aux:N #1
-      {
-        \if_num:w `#1 > \c_two_hundred_fifty_five
-          \exp_after:wN \str_if_bytes_aux:
-        \fi:
-      }
-    \cs_new_nopar:Npn \str_if_bytes_aux:
-      { \tl_map_break:n { \prg_return_false: \use_none:n } }
-  }
-\prg_new_protected_conditional:Npnn \str_aux_hexadecimal_test:N #1 { TF }
-  {
-    \tl_if_in:onTF { \tl_to_str:n { abcdef } } {#1}
-      {
-        \int_set:Nn \l_str_char_int
-          { \c_sixteen * \l_str_char_int + `#1 - 87 }
-        \prg_return_true:
-      }
-      {
-        \if_num:w \c_fifteen < "1 \exp_not:N #1 \exp_stop_f:
-          \int_set:Nn \l_str_char_int
-            { \c_sixteen * \l_str_char_int + "#1 }
-          \prg_return_true:
-        \else:
-          \prg_return_false:
-        \fi:
-      }
-  }
+\cs_new_nopar:Npn \str_if_contains_char_end:
+  { \prg_map_break:n { \prg_return_true: \use_none:n } }
 \prg_new_conditional:Npnn \str_aux_octal_use:N #1 { TF }
   {
-    \if_num:w \c_one < '1 #1 \exp_stop_f:
+    \if_num:w \c_one < '1 \token_to_str:N #1 \exp_stop_f:
       #1 \prg_return_true:
     \else:
       \prg_return_false:
@@ -473,21 +412,27 @@
   }
 \prg_new_conditional:Npnn \str_aux_hexadecimal_use:N #1 { TF }
   {
-    \if_num:w \c_two < "1 #1 \exp_stop_f:
+    \if_num:w \c_two < "1 \token_to_str:N #1 \exp_stop_f:
       #1 \prg_return_true:
     \else:
-      \if_case:w \int_eval:w `#1 - `a \int_eval_end:
-           A \prg_return_true:
-      \or: B \prg_return_true:
-      \or: C \prg_return_true:
-      \or: D \prg_return_true:
-      \or: E \prg_return_true:
-      \or: F \prg_return_true:
-      \else: \prg_return_false:
+      \if_case:w \int_eval:w
+          \exp_after:wN ` \token_to_str:N #1 - `a
+        \int_eval_end:
+           A
+      \or: B
+      \or: C
+      \or: D
+      \or: E
+      \or: F
+      \else:
+        \prg_return_false:
+        \exp_after:wN \use_none:n
       \fi:
+      \prg_return_true:
     \fi:
   }
 \group_begin:
+  \tl_clear:N \l_str_tmpa_tl
   \char_set_catcode_other:n { \c_zero }
   \tl_gset:Nx \g_str_result_tl { \tl_to_str:n { 0123456789ABCDEF } }
   \tl_map_inline:Nn \g_str_result_tl
@@ -496,15 +441,18 @@
     {
       \tl_map_inline:Nn \g_str_result_tl
         {
-          \char_set_lccode:nn { \c_zero } {"##1#1}
+          \char_set_lccode:nn { \c_zero } {"#1##1}
           \tl_to_lowercase:n
             {
               \tl_const:cx
-                { c_str_byte_ \int_eval:n {"##1#1} _tl }
-                { ^^@ ##1 #1 }
+                { c_str_byte_ \int_eval:n {"#1##1} _tl }
+                { ^^@ #1 ##1 }
+              \tl_put_right:Nn \l_str_tmpa_tl { ^^@ }
             }
         }
     }
+  \tl_const:Nx \c_str_positive_bytes_tl
+    { \exp_after:wN \use_none:n \l_str_tmpa_tl }
 \group_end:
 \tl_const:cn { c_str_byte_-1_tl } { { } \use_none:n { } }
 \cs_new:Npn \str_output_byte:n #1
@@ -545,17 +493,17 @@
   {
     \tl_gset:Nx \g_str_result_tl
       {
-        \exp_after:wN \str_aux_gmap_internal_result_loop:Nw
+        \exp_after:wN \str_aux_gmap_internal_result_loop:Nww
         \exp_after:wN #1
-          \g_str_result_tl \q_stop \prg_map_break: ,
+          \g_str_result_tl \q_mark \q_stop \prg_map_break: ,
         \prg_break_point:n { }
       }
   }
-\cs_new_nopar:Npn \str_aux_gmap_internal_result_loop:Nw #1#2,
+\cs_new_nopar:Npn \str_aux_gmap_internal_result_loop:Nww #1#2\q_mark #3,
   {
-    \use_none_delimit_by_q_stop:w #2 \q_stop
-    #1 {#2}
-    \str_aux_gmap_internal_result_loop:Nw #1
+    \use_none_delimit_by_q_stop:w #3 \q_stop
+    #1 {#3}
+    \str_aux_gmap_internal_result_loop:Nww #1
   }
 \cs_new_protected:Npn \str_input:Nn #1#2
   {
@@ -567,9 +515,11 @@
     \str_aux_escape:NNNn \token_to_str:N \token_to_str:N \token_to_str:N {#2}
     \tl_gset_eq:NN #1 \g_str_result_tl
   }
-\cs_new_eq:NN \str_aux_escape_unescaped:N \use:n
-\cs_new_eq:NN \str_aux_escape_escaped:N   \use:n
-\cs_new_eq:NN \str_aux_escape_raw:N       \use:n
+\cs_new_protected:Npn \str_escape_use:NNNn #1#2#3#4
+  {
+    \str_aux_escape:NNNn #1#2#3 {#4}
+    \g_str_result_tl
+  }
 \cs_new_protected:Npn \str_aux_escape:NNNn #1#2#3#4
   {
     \group_begin:
@@ -577,12 +527,15 @@
       \cs_set_nopar:Npn \str_aux_escape_escaped:N { #2 }
       \cs_set_nopar:Npn \str_aux_escape_raw:N { #3 }
       \int_set:Nn \tex_escapechar:D { 92 }
-      \str_aux_gset_other:Nn \g_str_result_tl {#4}
+      \str_gset_other:Nn \g_str_result_tl {#4}
+      \int_zero:N \l_str_tmpa_int
       \tl_gset:Nx \g_str_result_tl
         {
           \exp_after:wN \str_aux_escape_loop:N \g_str_result_tl
           \q_recursion_tail \q_recursion_stop
         }
+      \tl_gput_left:Nx \g_str_result_tl
+        { \str_aux_toks_range:nn \c_zero \l_str_tmpa_int }
     \group_end:
   }
 \cs_new_nopar:Npn \str_aux_escape_loop:N #1
@@ -598,6 +551,9 @@
       { \str_aux_escape_escaped:N #1 }
     \str_aux_escape_loop:N
   }
+\cs_new_eq:NN \str_aux_escape_unescaped:N \prg_do_nothing:
+\cs_new_eq:NN \str_aux_escape_escaped:N   \prg_do_nothing:
+\cs_new_eq:NN \str_aux_escape_raw:N       \prg_do_nothing:
 \cs_new_eq:cN
   { str_aux_escape_ \c_backslash_str q_recursion_tail :w }
   \use_none_delimit_by_q_recursion_stop:w
@@ -620,6 +576,8 @@
 \cs_new_nopar:cpn { str_aux_escape_/x:w } \str_aux_escape_loop:N
   {
     \if_false: { \fi: }
+    \tex_toks:D \l_str_tmpa_int \exp_after:wN { \g_str_result_tl }
+    \int_incr:N \l_str_tmpa_int
     \int_zero:N \l_str_char_int
     \str_aux_escape_x_test:N
   }
@@ -628,35 +586,36 @@
     \exp_not:N \token_if_eq_charcode:NNTF \c_space_token #1
       { \exp_not:N \str_aux_escape_x_test:N }
       {
-        \exp_not:N \token_if_eq_charcode:NNTF \c_lbrace_str #1
-          { \exp_not:N \str_aux_escape_x_braced_loop:N }
-          { \exp_not:N \str_aux_escape_x_unbraced_i:N #1 }
+        \l_str_char_int = "0
+          \exp_not:N \token_if_eq_charcode:NNTF \c_lbrace_str #1
+            { \exp_not:N \str_aux_escape_x_braced_loop:N }
+            { \exp_not:N \str_aux_escape_x_unbraced_i:N #1 }
       }
   }
-\cs_new_protected_nopar:Npn \str_aux_escape_x_unbraced_i:N #1
+\cs_new_nopar:Npn \str_aux_escape_x_unbraced_i:N #1
   {
-    \str_aux_hexadecimal_test:NTF #1
+    \str_aux_hexadecimal_use:NTF #1
       { \str_aux_escape_x_unbraced_ii:N }
-      { \str_aux_escape_x_end: #1 }
+      { \exp_stop_f: \str_aux_escape_x_end: #1 }
   }
-\cs_new_protected_nopar:Npn \str_aux_escape_x_unbraced_ii:N #1
+\cs_new_nopar:Npn \str_aux_escape_x_unbraced_ii:N #1
   {
     \token_if_eq_charcode:NNTF \c_space_token #1
       { \str_aux_escape_x_unbraced_ii:N }
       {
-        \str_aux_hexadecimal_test:NTF #1
-          { \str_aux_escape_x_end: }
-          { \str_aux_escape_x_end: #1 }
+        \str_aux_hexadecimal_use:NTF #1
+          { \exp_stop_f: \str_aux_escape_x_end: }
+          { \exp_stop_f: \str_aux_escape_x_end: #1 }
       }
   }
-\cs_new_protected_nopar:Npn \str_aux_escape_x_braced_loop:N #1
+\cs_new_nopar:Npn \str_aux_escape_x_braced_loop:N #1
   {
     \token_if_eq_charcode:NNTF \c_space_token #1
       { \str_aux_escape_x_braced_loop:N }
       {
-        \str_aux_hexadecimal_test:NTF #1
+        \str_aux_hexadecimal_use:NTF #1
           { \str_aux_escape_x_braced_loop:N }
-          { \str_aux_escape_x_braced_end:N #1 }
+          { \exp_stop_f: \str_aux_escape_x_braced_end:N #1 }
       }
   }
 \cs_new_protected_nopar:Npx \str_aux_escape_x_braced_end:N #1
@@ -675,7 +634,7 @@
       \tex_lccode:D \c_zero \l_str_char_int
       \tl_to_lowercase:n
         {
-          \tl_gput_right:Nx \g_str_result_tl
+          \tl_gset:Nx \g_str_result_tl
             { \if_false: } \fi:
             \str_aux_escape_raw:N ^^@
             \str_aux_escape_loop:N
@@ -683,13 +642,13 @@
     }
 \group_end:
 \cs_new_protected:Npn \str_set_convert:Nnnn
-  { \str_convert_aux_i:NNnnn \str_set:Nx }
+  { \str_convert_aux_i:NNnnn \tl_set_eq:NN }
 \cs_new_protected:Npn \str_gset_convert:Nnnn
-  { \str_convert_aux_i:NNnnn \str_gset:Nx }
+  { \str_convert_aux_i:NNnnn \tl_gset_eq:NN }
 \cs_new_protected:Npn \str_convert_aux_i:NNnnn #1#2#3#4#5
   {
     \group_begin:
-      \str_aux_gset_other:Nn \g_str_result_tl {#5}
+      \str_gset_other:Nn \g_str_result_tl {#5}
 
       \exp_after:wN \str_convert_aux_ii:wwwnn
         \tl_to_str:n {#3} /// \q_stop
@@ -831,11 +790,10 @@
     \char_set_catcode_comment:N \%
     \int_set:Nn \tex_endlinechar:D {32}
   }
-\int_new:N \l_str_encoding_int
 \cs_new_protected:Npn \str_convert_from_eight_bit:n #1
   {
     \group_begin:
-      \int_zero:N \l_str_encoding_int
+      \int_zero:N \l_str_tmpa_int
       \exp_last_unbraced:Nx \str_convert_from_eight_bit_load:nn
         { \tl_use:c { c_str_encoding_#1_tl } }
         { \q_stop \prg_map_break: } { }
@@ -850,24 +808,25 @@
 \cs_new_protected_nopar:Npn \str_convert_from_eight_bit_load:nn #1#2
   {
     \use_none_delimit_by_q_stop:w #1 \q_stop
-    \tex_dimen:D "#1 = \l_str_encoding_int sp \scan_stop:
-    \tex_skip:D \l_str_encoding_int = "#1 sp \scan_stop:
-    \tex_toks:D \l_str_encoding_int \exp_after:wN { \int_value:w "#2 }
-    \tex_advance:D \l_str_encoding_int \c_one
+    \tex_dimen:D "#1 = \l_str_tmpa_int sp \scan_stop:
+    \tex_skip:D \l_str_tmpa_int = "#1 sp \scan_stop:
+    \tex_toks:D \l_str_tmpa_int \exp_after:wN { \int_value:w "#2 }
+    \tex_advance:D \l_str_tmpa_int \c_one
     \str_convert_from_eight_bit_load:nn
   }
 \cs_new_protected_nopar:Npn \str_convert_from_eight_bit_load_missing:n #1
   {
     \use_none_delimit_by_q_stop:w #1 \q_stop
-    \tex_dimen:D "#1 = \l_str_encoding_int sp \scan_stop:
-    \tex_skip:D \l_str_encoding_int = "#1 sp \scan_stop:
-    \tex_toks:D \l_str_encoding_int \exp_after:wN { \int_value:w "FFFD }
-    \tex_advance:D \l_str_encoding_int \c_one
+    \tex_dimen:D "#1 = \l_str_tmpa_int sp \scan_stop:
+    \tex_skip:D \l_str_tmpa_int = "#1 sp \scan_stop:
+    \tex_toks:D \l_str_tmpa_int \exp_after:wN { \int_value:w "FFFD }
+    \tex_advance:D \l_str_tmpa_int \c_one
     \str_convert_from_eight_bit_load_missing:n
   }
 \cs_new:Npn \str_convert_from_eight_bit_aux:N #1
   {
-    \if_num:w \tex_dimen:D `#1 < \l_str_encoding_int
+    #1 \exp_not:N \q_mark
+    \if_num:w \tex_dimen:D `#1 < \l_str_tmpa_int
       \if_num:w \tex_skip:D \tex_dimen:D `#1 = `#1 \exp_stop_f:
         \tex_the:D \tex_toks:D \tex_dimen:D
       \fi:
@@ -877,7 +836,7 @@
 \cs_new_protected:Npn \str_convert_to_eight_bit:n #1
   {
     \group_begin:
-      \int_zero:N \l_str_encoding_int
+      \int_zero:N \l_str_tmpa_int
       \exp_last_unbraced:Nx \str_convert_to_eight_bit_load:nn
         { \tl_use:c { c_str_encoding_#1_tl } }
         { \q_stop \prg_map_break: } { }
@@ -888,17 +847,17 @@
 \cs_new_protected_nopar:Npn \str_convert_to_eight_bit_load:nn #1#2
   {
     \use_none_delimit_by_q_stop:w #1 \q_stop
-    \tex_dimen:D "#2 = \l_str_encoding_int sp \scan_stop:
-    \tex_skip:D \l_str_encoding_int = "#2 sp \scan_stop:
-    \exp_args:NNf \tex_toks:D \l_str_encoding_int
+    \tex_dimen:D "#2 = \l_str_tmpa_int sp \scan_stop:
+    \tex_skip:D \l_str_tmpa_int = "#2 sp \scan_stop:
+    \exp_args:NNf \tex_toks:D \l_str_tmpa_int
       { \str_output_byte:n { "#1 } }
-    \tex_advance:D \l_str_encoding_int \c_one
+    \tex_advance:D \l_str_tmpa_int \c_one
     \str_convert_to_eight_bit_load:nn
   }
 \cs_new:Npn \str_convert_to_eight_bit_aux:n #1
   {
     \if_num:w #1 < "8000 \exp_stop_f:
-      \if_num:w \tex_dimen:D #1 < \l_str_encoding_int
+      \if_num:w \tex_dimen:D #1 < \l_str_tmpa_int
         \if_num:w \tex_skip:D \tex_dimen:D #1 = #1 \exp_stop_f:
           \tex_the:D \tex_toks:D \tex_dimen:D #1 \exp_stop_f:
           \exp_after:wN \exp_after:wN \exp_after:wN \use_none:nn
@@ -907,7 +866,7 @@
       \str_convert_to_eight_bit_aux_ii:n {#1}
     \else:
       \msg_expandable_kernel_error:nnn
-        { str } { eight_bit-to-byte-overflow } {#1}
+        { str } { eight-bit-to-byte-overflow } {#1}
     \fi:
   }
 \cs_new:Npn \str_convert_to_eight_bit_aux_ii:n #1
@@ -956,30 +915,73 @@
 \cs_new_protected_nopar:Npn \str_convert_from_native:
   { \str_aux_gmap_result:N \str_convert_from_native_aux:N }
 \cs_new:Npn \str_convert_from_native_aux:N #1
-  { \int_value:w `#1 , }
+  { #1 \exp_not:N \q_mark \int_value:w `#1 , }
 \cs_new_protected_nopar:Npn \str_convert_to_native:
   {
     \tl_set_eq:NN \l_str_tmpa_tl \g_str_result_tl
+    \str_aux_convert_to_native:n
+      {
+        \exp_after:wN \str_convert_to_native_aux:w
+        \l_str_tmpa_tl \q_mark { \q_stop \prg_map_break: } ,
+      }
+  }
+\cs_new_protected_nopar:Npn \str_convert_to_native_aux:w #1\q_mark #2,
+  {
+    \use_none_delimit_by_q_stop:w #2 \q_stop
+    \str_aux_convert_to_native_step:n {#2}
+    \str_convert_to_native_aux:w
+  }
+\cs_new_protected_nopar:Npn \str_aux_convert_to_native:n #1
+  {
+    \tex_lccode:D \c_zero \c_zero
+    \int_zero:N \l_str_tmpa_int
     \tl_gclear:N \g_str_result_tl
-    \tex_afterassignment:D \str_convert_to_native_aux:w
-    \l_str_char_int = \l_str_tmpa_tl \c_zero \prg_map_break: ,
-    \prg_break_point:n { }
+    #1
+    \prg_break_point:n { \str_aux_convert_to_native_flush: }
+  }
+\cs_new_protected_nopar:Npn \str_aux_convert_to_native_step:n #1
+  {
+    \if_num:w \l_str_tmpa_int = \c_two_hundred_fifty_five
+      \str_aux_convert_to_native_flush:
+      \l_str_tmpa_int \c_zero
+    \fi:
+    \tex_advance:D \l_str_tmpa_int \c_one
+    \if_int_compare:w #1 > \c_max_char_int
+      \msg_kernel_error:nnx { str } { overflow } {#1}
+      \tex_lccode:D \l_str_tmpa_int \c_str_replacement_char_int
+    \else:
+      \tex_lccode:D \l_str_tmpa_int \int_eval:w #1 \int_eval_end:
+    \fi:
+  }
+\cs_new_protected_nopar:Npn \str_aux_convert_to_native_flush:
+  {
+    \use:x
+      {
+        \tl_to_lowercase:n
+          {
+            \tl_gput_right:Nx \exp_not:N \g_str_result_tl
+              {
+                \exp_after:wN \str_aux_convert_to_native_filter:N
+                  \c_str_positive_bytes_tl
+                  { ? = \c_zero \fi: \prg_map_break: }
+                \prg_break_point:n { }
+              }
+          }
+      }
   }
 \group_begin:
-  \char_set_catcode_other:n { `\^^@ }
-  \cs_new_protected_nopar:Npn \str_convert_to_native_aux:w #1 ,
+  \char_set_catcode_other:n { 0 }
+  \cs_new:Npn \str_aux_convert_to_native_filter:N #1
     {
-      #1
-      \if_int_compare:w \l_str_char_int > \c_max_char_int
-        \msg_kernel_error:nnx { str } { overflow }
-          { \int_use:N \l_str_char_int }
+      \if_num:w `#1 > \l_str_tmpa_int
+        \exp_after:wN \prg_map_break:
+      \fi:
+      \if_num:w \tex_lccode:D `#1 = \c_zero
+        ^^@
       \else:
-        \tex_lccode:D \c_zero \l_str_char_int
-        \tl_to_lowercase:n
-          { \tex_xdef:D \g_str_result_tl { \g_str_result_tl ^^@ } }
+        #1
       \fi:
-      \tex_afterassignment:D \str_convert_to_native_aux:w
-      \l_str_char_int =
+      \str_aux_convert_to_native_filter:N
     }
 \group_end:
 \msg_kernel_new:nnnn { str } { x-missing-brace }
diff --git a/Master/texmf-dist/tex/latex/l3experimental/l3str/l3tl-analysis.sty b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3tl-analysis.sty
new file mode 100644
index 00000000000..84479cc1543
--- /dev/null
+++ b/Master/texmf-dist/tex/latex/l3experimental/l3str/l3tl-analysis.sty
@@ -0,0 +1,402 @@
+%%
+%% This is file `l3tl-analysis.sty',
+%% generated with the docstrip utility.
+%%
+%% The original source files were:
+%%
+%% l3tl-analysis.dtx  (with options: `package')
+%% 
+%% EXPERIMENTAL CODE
+%% 
+%% Do not distribute this file without also distributing the
+%% source files specified above.
+%% 
+%% Do not distribute a modified version of this file.
+%% 
+%% File: l3tl-analysis.dtx Copyright (C) 2011 The LaTeX3 Project
+%%
+%% It may be distributed and/or modified under the conditions of the
+%% LaTeX Project Public License (LPPL), either version 1.3c of this
+%% 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
+%%
+%% This file is part of the "l3experimental bundle" (The Work in LPPL)
+%% and all files in that bundle must be distributed together.
+%%
+%% The released version of this bundle is available from CTAN.
+%%
+%% -----------------------------------------------------------------------
+%%
+%% The development version of the bundle can be found at
+%%
+%%    http://www.latex-project.org/svnroot/experimental/trunk/
+%%
+%% for those people who are interested.
+%%
+%%%%%%%%%%%
+%% NOTE: %%
+%%%%%%%%%%%
+%%
+%%   Snapshots taken from the repository represent work in progress and may
+%%   not work or may contain conflicting material!  We therefore ask
+%%   people _not_ to put them into distributions, archives, etc. without
+%%   prior consultation with the LaTeX3 Project.
+%%
+%% -----------------------------------------------------------------------
+\RequirePackage{expl3}
+\GetIdInfo$Id: l3tl-analysis.dtx 3039 2011-12-08 09:22:35Z bruno $
+  {L3 Experimental Analysis of Token lists}
+\ProvidesExplPackage
+  {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription}
+\RequirePackage{l3str}
+\int_new:N \l_tl_analysis_normal_int
+\int_new:N \l_tl_analysis_index_int
+\int_new:N \l_tl_analysis_nesting_int
+\int_new:N \l_tl_analysis_char_int
+\int_new:N \l_tl_analysis_type_int
+\tl_new:N \g_tl_analysis_result_tl
+\cs_new_protected_nopar:Npn \tl_analysis_extract_charcode:
+  {
+    \exp_after:wN \tl_analysis_extract_charcode_aux:w
+      \token_to_meaning:N \l_tl_analysis_token
+  }
+\cs_new_protected_nopar:Npn \tl_analysis_extract_charcode_aux:w #1 ~ #2 ~ { ` }
+\cs_new:Npn \tl_analysis_cs_space_count:NN #1 #2
+  {
+    \exp_after:wN #1
+    \int_value:w \int_eval:w \c_zero
+      \exp_after:wN \tl_analysis_cs_space_count:w
+        \token_to_str:N #2
+        \fi: \tl_analysis_cs_space_count_end:w ; ~ !
+  }
+\cs_new:Npn \tl_analysis_cs_space_count:w #1 ~
+  {
+    \if_false: #1 #1 \fi:
+    + \c_one
+    \tl_analysis_cs_space_count:w
+  }
+\cs_new:Npn \tl_analysis_cs_space_count_end:w ; #1 \fi: #2 !
+  { \exp_after:wN ; \int_value:w \str_length_ignore_spaces:n {#1} ; }
+\cs_new_protected:Npn \tl_analysis:n #1
+  {
+    \group_begin:
+      \group_align_safe_begin:
+        \tl_analysis_setup:n {#1}
+        \tl_analysis_i:n {#1}
+        \tl_analysis_ii:n {#1}
+      \group_align_safe_end:
+    \group_end:
+  }
+\cs_new_protected:Npn \tl_set_analysis:Nn #1#2
+  {
+    \tl_analysis:n {#2}
+    \tl_set_eq:NN #1 \g_tl_analysis_result_tl
+  }
+\cs_new_protected:Npn \tl_analysis_setup:n #1
+  {
+    \int_set:Nn \tex_escapechar:D { 92 }
+    \exp_after:wN \tl_analysis_disable_loop:N
+      \tl_to_str:n {#1} { ~ } { ? ~ \prg_map_break: }
+    \prg_break_point:n { }
+  }
+\group_begin:
+  \char_set_catcode_active:N \^^@
+  \cs_new_protected_nopar:Npn \tl_analysis_disable_loop:N #1
+    {
+      \tex_lccode:D \c_zero `#1 ~
+      \tl_to_lowercase:n { \tex_let:D ^^@ } \c_undefined:D
+      \tl_analysis_disable_loop:N
+    }
+\group_end:
+\cs_new_protected:Npn \tl_analysis_i:n #1
+  {
+    \int_zero:N \l_tl_analysis_normal_int
+    \int_zero:N \l_tl_analysis_index_int
+    \int_zero:N \l_tl_analysis_nesting_int
+    \if_false: { \fi: \tl_analysis_i_loop:w #1 }
+    \int_decr:N \l_tl_analysis_index_int
+  }
+\cs_new_protected_nopar:Npn \tl_analysis_i_loop:w
+  { \tex_futurelet:D \l_tl_analysis_token \tl_analysis_i_type:w }
+\cs_new_protected_nopar:Npn \tl_analysis_i_type:w
+  {
+    \l_tl_analysis_type_int =
+      \if_meaning:w \l_tl_analysis_token \c_space_token
+        \c_zero
+      \else:
+        \if_catcode:w \exp_not:N \l_tl_analysis_token \c_group_begin_token
+          \c_one
+        \else:
+          \if_catcode:w \exp_not:N \l_tl_analysis_token \c_group_end_token
+            \c_minus_one
+          \else:
+            \c_two
+          \fi:
+        \fi:
+      \fi:
+    \if_case:w \l_tl_analysis_type_int
+         \exp_after:wN \tl_analysis_i_space:w
+    \or: \exp_after:wN \tl_analysis_i_bgroup:w
+    \or: \exp_after:wN \tl_analysis_i_safe:N
+    \else: \exp_after:wN \tl_analysis_i_egroup:w
+    \fi:
+  }
+\cs_new_protected:Npn \tl_analysis_i_safe:N #1
+  {
+    \if_charcode:w
+        \scan_stop:
+        \exp_after:wN \use_none:n \token_to_str:N #1 \prg_do_nothing:
+        \scan_stop:
+      \int_incr:N \l_tl_analysis_normal_int
+    \else:
+      \tl_analysis_cs_space_count:NN \tl_analysis_i_cs:ww #1
+    \fi:
+    \tl_analysis_i_loop:w
+  }
+\cs_new_protected:Npn \tl_analysis_i_cs:ww #1; #2;
+  {
+    \if_num:w #1 > \c_zero
+      \tex_skip:D \l_tl_analysis_index_int
+        = \int_eval:w \l_tl_analysis_normal_int + \c_one sp \scan_stop:
+      \tex_advance:D \l_tl_analysis_index_int #1 \exp_stop_f:
+      \l_tl_analysis_normal_int #2 \exp_stop_f:
+    \else:
+      \tex_advance:D \l_tl_analysis_normal_int #2 \exp_stop_f:
+    \fi:
+  }
+\cs_new_protected_nopar:Npn \tl_analysis_i_space:w
+  {
+    \tex_afterassignment:D \tl_analysis_i_space_test:w
+    \exp_after:wN \cs_set_eq:NN
+    \exp_after:wN \l_tl_analysis_token
+    \token_to_str:N
+  }
+\cs_new_protected_nopar:Npn \tl_analysis_i_space_test:w
+  {
+    \if_meaning:w \l_tl_analysis_token \c_space_token
+      \tex_toks:D \l_tl_analysis_index_int { \exp_not:n { ~ } }
+      \tl_analysis_i_store:
+    \else:
+      \int_incr:N \l_tl_analysis_normal_int
+    \fi:
+    \tl_analysis_i_loop:w
+  }
+\group_begin:
+  \char_set_catcode_group_begin:N \^^@
+  \char_set_catcode_group_end:N \^^E
+  \cs_new_protected_nopar:Npn \tl_analysis_i_bgroup:w
+    { \tl_analysis_i_group:nw { \exp_after:wN ^^@ \if_false: ^^E \fi: } }
+  \char_set_catcode_group_begin:N \^^B
+  \char_set_catcode_group_end:N \^^@
+  \cs_new_protected_nopar:Npn \tl_analysis_i_egroup:w
+    { \tl_analysis_i_group:nw { \if_false: ^^B \fi: ^^@ } }
+\group_end:
+\cs_new_protected_nopar:Npn \tl_analysis_i_group:nw #1
+  {
+    \l_tl_analysis_char_int = \tl_analysis_extract_charcode: \scan_stop:
+    \tex_lccode:D \c_zero \l_tl_analysis_char_int
+    \tl_to_lowercase:n { \tex_toks:D \l_tl_analysis_index_int {#1} }
+    \if_num:w \l_tl_analysis_char_int = \tex_escapechar:D
+      \int_set:Nn \tex_escapechar:D { 139 - \tex_escapechar:D }
+    \fi:
+    \tex_afterassignment:D \tl_analysis_i_group_test:w
+    \exp_after:wN \cs_set_eq:NN
+    \exp_after:wN \l_tl_analysis_token
+    \token_to_str:N
+  }
+\cs_new_protected_nopar:Npn \tl_analysis_i_group_test:w
+  {
+    \if_num:w \tl_analysis_extract_charcode: = \l_tl_analysis_char_int
+      \tl_analysis_i_store:
+    \else:
+      \int_incr:N \l_tl_analysis_normal_int
+    \fi:
+    \tl_analysis_i_loop:w
+  }
+\cs_new_protected_nopar:Npn \tl_analysis_i_store:
+  {
+    \tex_advance:D \l_tl_analysis_nesting_int \l_tl_analysis_type_int
+    \if_num:w \l_tl_analysis_char_int = \c_thirty_two
+      \tex_multiply:D \l_tl_analysis_type_int \c_two
+    \fi:
+    \tex_skip:D \l_tl_analysis_index_int
+      = \l_tl_analysis_normal_int sp plus \l_tl_analysis_type_int sp \scan_stop:
+    \int_incr:N \l_tl_analysis_index_int
+    \int_zero:N \l_tl_analysis_normal_int
+    \if_num:w \l_tl_analysis_nesting_int = \c_minus_one
+      \cs_set_eq:NN \tl_analysis_i_loop:w \scan_stop:
+    \fi:
+  }
+\cs_new_protected:Npn \tl_analysis_ii:n #1
+  {
+    \tl_gset:Nx \g_tl_analysis_result_tl
+      {
+        \tl_analysis_ii_loop:w 0; #1
+        \prg_break_point:n { }
+      }
+  }
+\cs_new:Npn \tl_analysis_ii_loop:w #1;
+  {
+    \exp_after:wN \tl_analysis_ii_normals:ww
+      \int_value:w \tex_skip:D #1 ; #1 ;
+  }
+\cs_new:Npn \tl_analysis_ii_normals:ww #1;
+  {
+    \if_num:w #1 = \c_zero
+      \tl_analysis_ii_special:w
+    \fi:
+    \tl_analysis_ii_normal:wwN #1;
+  }
+\cs_new:Npn \tl_analysis_ii_normal:wwN #1; #2; #3
+  {
+    \exp_not:n { \exp_not:n { #3 } } \exp_not:N \q_mark
+    \if_charcode:w
+        \scan_stop:
+        \exp_after:wN \use_none:n \token_to_str:N #3 \prg_do_nothing:
+        \scan_stop:
+      \exp_after:wN \tl_analysis_ii_char:Nww
+    \else:
+      \exp_after:wN \tl_analysis_ii_cs:Nww
+    \fi:
+    #3 #1; #2;
+  }
+\cs_new:Npn \tl_analysis_ii_char:Nww #1
+  {
+    \if_meaning:w #1 \c_undefined:D            D \else:
+    \if_catcode:w #1 \c_catcode_other_token    C \else:
+    \if_catcode:w #1 \c_catcode_letter_token   B \else:
+    \if_catcode:w #1 \c_math_toggle_token      3 \else:
+    \if_catcode:w #1 \c_alignment_token        4 \else:
+    \if_catcode:w #1 \c_math_superscript_token 7 \else:
+    \if_catcode:w #1 \c_math_subscript_token   8 \else:
+      6
+    \fi: \fi: \fi: \fi: \fi: \fi: \fi:
+    \int_value:w `#1 ,
+    \exp_after:wN \tl_analysis_ii_normals:ww
+      \int_use:N \int_eval:w \c_minus_one +
+  }
+\cs_new:Npn \tl_analysis_ii_cs:Nww #1
+  {
+    0 -1 ,
+    \tl_analysis_cs_space_count:NN \tl_analysis_ii_cs_test:ww #1
+  }
+\cs_new:Npn \tl_analysis_ii_cs_test:ww #1 ; #2 ; #3; #4;
+  {
+    \exp_after:wN \tl_analysis_ii_normals:ww
+    \int_use:N \int_eval:w
+    \if_num:w #1 = \c_zero
+      #3
+    \else:
+      \tex_skip:D \int_eval:w #4 + #1 \int_eval_end:
+    \fi:
+    - #2
+    \exp_after:wN ;
+    \int_use:N \int_eval:w #4 + #1;
+  }
+\cs_new:Npn \tl_analysis_ii_special:w \fi: \tl_analysis_ii_normal:wwN 0; #1;
+  {
+    \fi:
+    \if_num:w #1 = \l_tl_analysis_index_int
+      \exp_after:wN \prg_map_break:
+    \fi:
+    \tex_the:D \tex_toks:D #1 \exp_stop_f: \exp_not:N \q_mark
+    \if_case:w \etex_gluestretch:D \tex_skip:D #1 \exp_stop_f:
+           A
+    \or:   1
+    \or:   1
+    \else: 2
+    \fi:
+    \if_int_odd:w \etex_gluestretch:D \tex_skip:D #1 \exp_stop_f:
+      \exp_after:wN \tl_analysis_ii_special_char:wN \int_use:N
+    \else:
+      \exp_after:wN \tl_analysis_ii_special_space:w \int_use:N
+    \fi:
+    \int_eval:w \c_one + #1 \exp_after:wN ;
+    \token_to_str:N
+  }
+\cs_new:Npn \tl_analysis_ii_special_char:wN #1 ; #2
+  {
+    \int_value:w `#2 ,
+    \tl_analysis_ii_loop:w #1 ;
+  }
+\cs_new:Npn \tl_analysis_ii_special_space:w #1 ; ~
+  {
+    32 ,
+    \tl_analysis_ii_loop:w #1 ;
+  }
+\cs_new_protected:Npn \tl_show_analysis:N #1
+  {
+    \exp_args:No \tl_analysis:n {#1}
+    \msg_aux_show:Nnx #1
+      { tl-analysis }
+      {
+        \exp_after:wN \tl_show_analysis_loop:wNw \g_tl_analysis_result_tl
+          \q_mark { ? \prg_map_break: } ,
+        \prg_break_point:n { }
+      }
+  }
+\cs_new_protected:Npn \tl_show_analysis:n #1
+  {
+    \tl_set:Nn \l_tl_tmpa_tl {#1}
+    \tl_show_analysis:N \l_tl_tmpa_tl
+  }
+\cs_new:Npn \tl_show_analysis_loop:wNw #1 \q_mark #2 #3,
+  {
+    \use_none:n #2
+    \iow_newline: > \c_space_tl \c_space_tl
+    \if_num:w "#2 = \c_zero
+      \exp_after:wN \tl_show_analysis_cs:n
+    \else:
+      \if_num:w "#2 = \c_thirteen
+        \exp_after:wN \exp_after:wN
+        \exp_after:wN \tl_show_analysis_active:n
+      \else:
+        \exp_after:wN \exp_after:wN
+        \exp_after:wN \tl_show_analysis_normal:n
+      \fi:
+    \fi:
+    {#1}
+    \tl_show_analysis_loop:wNw
+  }
+\cs_new:Npn \tl_show_analysis_normal:n #1
+  {
+    \exp_after:wN \token_to_str:N #1 ~
+    ( \exp_after:wN \token_to_meaning:N #1 )
+  }
+\cs_new:Npn \tl_show_analysis_cs:n #1
+  { \exp_args:No \tl_show_analysis_long:nn {#1} { control~sequence= } }
+\cs_new:Npn \tl_show_analysis_active:n #1
+  { \exp_args:No \tl_show_analysis_long:nn {#1} { active~character= } }
+\cs_new:Npn \tl_show_analysis_long:nn #1
+  {
+    \exp_args:Noo \tl_show_analysis_long_aux:nnn
+      { \token_to_str:N #1 }
+      { \token_to_meaning:N #1 }
+  }
+\cs_new_nopar:Npn \tl_show_analysis_long_aux:nnn #1#2#3
+  {
+    \int_compare:nNnTF
+      { \str_length:n { >>> #1 ~ ( #3 #2 ) } }
+      > { \l_iow_line_length_int }
+      {
+        \str_substr:nnn { >>> #1 ~ ( #3 #2 ) } \c_three
+          { \l_iow_line_length_int - \str_length:N \c_tl_show_analysis_etc_str }
+        \c_tl_show_analysis_etc_str
+      }
+      {#1~(#3#2)}
+  }
+\str_const:Nx \c_tl_show_analysis_etc_str % (
+  { \iow_char:N \\ETC. ) }
+\msg_kernel_new:nnn { tl-analysis } { show }
+  {
+    Token~list~
+    \str_if_eq:nnF {#1} { \l_tl_tmpa_tl } { \token_to_str:N #1~}
+    \tl_if_empty:NTF #1
+      { is~empty }
+      { contains~the~tokens: }
+  }
+%% 
+%%
+%% End of file `l3tl-analysis.sty'.
diff --git a/Master/texmf-dist/tex/latex/l3experimental/xgalley/l3galley.sty b/Master/texmf-dist/tex/latex/l3experimental/xgalley/l3galley.sty
index e8a3345204f..28bc6b50dc5 100644
--- a/Master/texmf-dist/tex/latex/l3experimental/xgalley/l3galley.sty
+++ b/Master/texmf-dist/tex/latex/l3experimental/xgalley/l3galley.sty
@@ -48,14 +48,11 @@
 %% -----------------------------------------------------------------------
 %%
 \RequirePackage{l3names}
-\GetIdInfo$Id: l3galley.dtx 2938 2011-10-25 18:41:20Z joseph $
+\GetIdInfo$Id: l3galley.dtx 3071 2011-12-20 20:14:00Z bruno $
   {L3 Experimental galley code}
 \ProvidesExplPackage
   {\ExplFileName}{\ExplFileDate}{\ExplFileVersion}{\ExplFileDescription}
 \package_check_loaded_expl:
-\cs_new_protected:Npn \scan_marker_new:N #1
-  { \cs_new_eq:NN #1 \scan_stop: }
-\cs_generate_variant:Nn \scan_marker_new:N { c }
 \cs_new_protected_nopar:Npn \galley_leave_vmode:
   { \tex_unhbox:D \c_empty_box }
 \clist_new:N \l_galley_parshape_left_indent_clist
@@ -193,7 +190,7 @@
       \galley_restore_parameters:
     \group_end:
   }
-\scan_marker_new:N \s_par_omit
+\scan_new:N \s_par_omit
 \cs_new_protected_nopar:Npn \galley_std_par:
   {
     \s_par_omit