zref-check (17sep21)

git-svn-id: svn://tug.org/texlive/trunk@60527 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 206 insertions, 184 deletions

diff --git a/Master/texmf-dist/tex/latex/zref-check/zref-check.sty b/Master/texmf-dist/tex/latex/zref-check/zref-check.sty
index ea26b0766bc..bd1e9ccb2d0 100644
--- a/Master/texmf-dist/tex/latex/zref-check/zref-check.sty
+++ b/Master/texmf-dist/tex/latex/zref-check/zref-check.sty
@@ -55,7 +55,7 @@
       }%
     \endinput
   }%
-\ProvidesExplPackage {zref-check} {2021-08-17} {0.2.0}
+\ProvidesExplPackage {zref-check} {2021-09-16} {0.2.1}
   {Flexible cross-references with contextual checks based on zref}
 \RequirePackage { zref-user }
 \RequirePackage { zref-abspage }
@@ -73,41 +73,47 @@
   { \int_gincr:N \g__zrefcheck_abssec_int }
 \zref@newprop { zc@abssec } [0] { \int_use:N \g__zrefcheck_abssec_int }
 \zref@addprop \ZREF@mainlist { zc@abssec }
-\zref@newlist { zrefcheck }
-\zref@addprops { zrefcheck }
+\zref@newlist { zrefcheck-check }
+\zref@addprops { zrefcheck-check }
   {
-    page ,
+    page , % for messages
     abspage ,
     zc@abschap ,
     zc@abssec
   }
-\cs_new:Npn \__zrefcheck_message:nnnn #1#2#3#4
+\zref@newlist { zrefcheck-target }
+\zref@addprops { zrefcheck-target }
+  {
+    page , % so that \zpageref can refer to it
+    abspage ,
+    zc@abschap ,
+    zc@abssec
+  }
+\zref@newlist { zrefcheck-end }
+\zref@addprops { zrefcheck-end }
+  {
+    abspage ,
+    zc@abschap ,
+    zc@abssec
+  }
+\cs_new_protected:Npn \__zrefcheck_message:nnnn #1#2#3#4
   {
     \use:c { msg_ \l__zrefcheck_msglevel_tl :nnnnn }
       { zref-check } {#1} {#2} {#3} {#4}
   }
 \cs_generate_variant:Nn \__zrefcheck_message:nnnn { nnnx }
 \msg_new:nnn { zref-check } { check-failed }
-  {
-    Failed~check~'#1'~for~label~'#2' \iow_newline:
-    on~page~#3~on~input~line~\msg_line_number:.
-  }
+  { Failed~check~'#1'~for~label~'#2'~on~page~#3~\msg_line_context:. }
 \msg_new:nnn { zref-check } { double-check }
-  {
-    Double-check~'#1'~for~label~'#2' \iow_newline:
-    on~page~#3~on~input~line~\msg_line_number:.
-  }
+  { Double-check~'#1'~for~label~'#2'~on~page~#3~\msg_line_context:. }
 \msg_new:nnn { zref-check } { check-missing }
-  { Check~'#1'~not~defined~on~input~line~\msg_line_number:. }
+  { Check~'#1'~not~defined~\msg_line_context:. }
 \msg_new:nnn { zref-check } { property-undefined }
-  { Property~'#1'~not~defined~on~input~line~\msg_line_number:. }
+  { Property~'#1'~not~defined~\msg_line_context:. }
 \msg_new:nnn { zref-check } { property-not-in-label }
-  { Label~'#1'~has~no~property~'#2'~on~input~line~\msg_line_number:. }
+  { Label~'#1'~has~no~property~'#2'~\msg_line_context:. }
 \msg_new:nnn { zref-check } { property-not-integer }
-  {
-    Property~'#1'~for~label~'#2'~not~an~integer \iow_newline:
-    on~input~line~\msg_line_number:.
-  }
+  { Property~'#1'~for~label~'#2'~not~an~integer~\msg_line_context:. }
 \msg_new:nnn { zref-check } { hyperref-preamble-only }
   {
     Option~'hyperref'~only~available~in~the~preamble. \iow_newline:
@@ -121,14 +127,11 @@
     Use~option~'msglevel'~instead.
   }
 \msg_new:nnn { zref-check } { option-preamble-only }
-  {
-    Option~'#1'~only~available~in~the~preamble \iow_newline:
-    on~input~line~\msg_line_number:.
-  }
+  { Option~'#1'~only~available~in~the~preamble~\msg_line_context:. }
 \msg_new:nnn { zref-check } { closerange-not-positive-integer }
   {
-    Option~'closerange'~not~a~positive~integer \iow_newline:
-    on~input~line~\msg_line_number:.~Using~default~value.
+    Option~'closerange'~not~a~positive~integer~\msg_line_context:.~
+    Using~default~value.
   }
 \msg_new:nnn { zref-check } { labelcmd-undefined }
   {
@@ -182,7 +185,7 @@
         \bool_if:NT \l__zrefcheck_use_hyperref_bool
           {
             \RequirePackage { zref-hyperref }
-            \zref@addprop { zrefcheck } { anchor }
+            \zref@addprop { zrefcheck-target } { anchor }
           }
       }
       {
@@ -282,8 +285,8 @@
       } ,
     labelcmd .value_required:n = true ,
   }
-\cs_new:Npn \__zrefcheck_target_label:n #1
-  { \zref@labelbylist {#1} { zrefcheck } }
+\cs_new_protected:Npn \__zrefcheck_target_label:n #1
+  { \zref@labelbylist {#1} { zrefcheck-target } }
 \AddToHook { begindocument }
   {
     \bool_if:NT \l__zrefcheck_target_label_bool
@@ -292,7 +295,7 @@
           { \tl_clear:N \l__zrefcheck_target_label_tl }
         \cs_if_exist:cTF { \l__zrefcheck_target_label_tl }
           {
-            \cs_set:Npx \__zrefcheck_target_label:n #1
+            \cs_set_protected:Npx \__zrefcheck_target_label:n #1
               {
                 \exp_not:o
                   { \cs:w \l__zrefcheck_target_label_tl \cs_end: }
@@ -300,7 +303,7 @@
               }
           }
           {
-            \exp_args:NnnV \msg_warning:nnn { zref-check }
+            \exp_args:Nnno \msg_warning:nnn { zref-check }
               { labelcmd-undefined } { \l__zrefcheck_target_label_tl }
           }
       }
@@ -359,7 +362,7 @@
 \setcounter { zrefcheck } { 0 }
 \cs_new:Npn \__zrefcheck_check_lblfmt:n #1 { zrefcheck@ \int_use:N #1 }
 \cs_new:Npn \__zrefcheck_end_lblfmt:n #1 { #1 @zrefcheck }
-\cs_new:Npn \zrefcheck_get_astl:nnn #1#2#3
+\cs_new_protected:Npn \zrefcheck_get_astl:nnn #1#2#3
   {
     \tl_clear:N #3
     \tl_if_eq:nnTF {#2} { lblseq }
@@ -392,7 +395,7 @@
   }
 \bool_new:N \l__zrefcheck_integer_bool
 \tl_new:N \l__zrefcheck_propval_tl
-\cs_new:Npn \zrefcheck_get_asint:nnn #1#2#3
+\cs_new_protected:Npn \zrefcheck_get_asint:nnn #1#2#3
   {
     \zrefcheck_get_astl:nnn {#1} {#2} { \l__zrefcheck_propval_tl }
     \__zrefcheck_is_integer:nTF { \l__zrefcheck_propval_tl }
@@ -409,27 +412,24 @@
           }
       }
   }
-\NewDocumentCommand \zcheck
-  { s O { } > { \SplitList { , } } m m }
+\NewDocumentCommand \zcheck { s O { } m m }
   { \zref@wrapper@babel \__zrefcheck_zcheck:nnnn {#3} {#1} {#2} {#4} }
+\seq_new:N \l__zrefcheck_zcheck_labels_seq
 \int_new:N \g__zrefcheck_id_int
 \tl_new:N \l__zrefcheck_checkbeg_tl
-\tl_new:N \l__zrefcheck_checkend_tl
 \tl_new:N \l__zrefcheck_link_label_tl
 \tl_new:N \l__zrefcheck_link_anchor_tl
 \bool_new:N \l__zrefcheck_link_star_bool
-\cs_new:Npn \__zrefcheck_zcheck:nnnn #1#2#3#4
+\cs_new_protected:Npn \__zrefcheck_zcheck:nnnn #1#2#3#4
   {
     \group_begin:
-      \__zrefcheck_set_checks_keys:
-      \keys_set:nn { zref-check } {#3}
+      \keys_set:nn { zref-check / zcheck } {#3}
+      \seq_set_from_clist:Nn \l__zrefcheck_zcheck_labels_seq {#1}
       \int_gincr:N \g__zrefcheck_id_int
       \tl_set:Nx \l__zrefcheck_checkbeg_tl
         { \__zrefcheck_check_lblfmt:n { \g__zrefcheck_id_int } }
-      \tl_set:Nx \l__zrefcheck_checkend_tl
-        { \__zrefcheck_end_lblfmt:n { \l__zrefcheck_checkbeg_tl } }
-      \zref@labelbylist { \l__zrefcheck_checkbeg_tl } { zrefcheck }
-      \tl_set:Nn \l__zrefcheck_link_label_tl { \tl_head:n {#1} }
+      \zref@labelbylist { \l__zrefcheck_checkbeg_tl } { zrefcheck-check }
+      \seq_get:NN \l__zrefcheck_zcheck_labels_seq \l__zrefcheck_link_label_tl
       \bool_set:Nn \l__zrefcheck_link_star_bool {#2}
       \zref@ifrefundefined { \l__zrefcheck_link_label_tl }
         {#4}
@@ -447,10 +447,15 @@
             }
             {#4}
         }
-      \zref@labelbylist { \l__zrefcheck_checkend_tl } { zrefcheck }
-      \tl_map_function:nN {#1} \zref@refused
-      \__zrefcheck_run_checks:nnv
-        { \l__zrefcheck_zcheck_checks_seq } {#1} { l__zrefcheck_checkbeg_tl }
+      \bool_if:NT \l__zrefcheck_zcheck_end_label_bool
+        {
+          \zref@labelbylist
+            { \__zrefcheck_end_lblfmt:n { \l__zrefcheck_checkbeg_tl } }
+            { zrefcheck-end }
+        }
+      \seq_map_function:NN \l__zrefcheck_zcheck_labels_seq \zref@refused
+      \__zrefcheck_run_checks:nnx { \l__zrefcheck_zcheck_checks_seq }
+        { \l__zrefcheck_zcheck_labels_seq } { \l__zrefcheck_checkbeg_tl }
     \group_end:
   }
 \NewDocumentCommand \zctarget { m +m }
@@ -460,7 +465,7 @@
     \zref@wrapper@babel \__zrefcheck_target_label:n {#1}
     #2
     \zref@wrapper@babel
-      \zref@labelbylist { \__zrefcheck_end_lblfmt:n {#1} } { zrefcheck }
+      \zref@labelbylist { \__zrefcheck_end_lblfmt:n {#1} } { zrefcheck-end }
     \group_end:
   }
 \NewDocumentEnvironment {zcregion} { m }
@@ -470,128 +475,83 @@
   }
   {
     \zref@wrapper@babel
-      \zref@labelbylist { \__zrefcheck_end_lblfmt:n {#1} } { zrefcheck }
+      \zref@labelbylist { \__zrefcheck_end_lblfmt:n {#1} } { zrefcheck-end }
+  }
+\seq_new:N \c__zrefcheck_single_label_checks_seq
+\seq_set_from_clist:Nn \c__zrefcheck_single_label_checks_seq
+  {
+    thischap ,
+    prevchap ,
+    nextchap ,
+    chapsbefore ,
+    chapsafter ,
+    thissec ,
+    prevsec ,
+    nextsec ,
+    secsbefore ,
+    secsafter ,
   }
 \seq_new:N \l__zrefcheck_zcheck_checks_seq
-\cs_new:Npn \__zrefcheck_set_checks_keys:
+\bool_new:N \l__zrefcheck_zcheck_end_label_bool
+\keys_define:nn { } { zref-check / zcheck .inherit:n = zref-check }
+\clist_map_inline:nn
+  {
+    thispage ,
+    prevpage ,
+    nextpage ,
+    facing ,
+    pagegap ,
+    above ,
+    below ,
+    pagesbefore ,
+    ppbefore ,
+    pagesafter ,
+    ppafter ,
+    before ,
+    after ,
+    thischap ,
+    prevchap ,
+    nextchap ,
+    chapsbefore ,
+    chapsafter ,
+    thissec ,
+    prevsec ,
+    nextsec ,
+    secsbefore ,
+    secsafter ,
+    close ,
+    far ,
+  }
   {
-    \keys_define:nn  { zref-check }
+    \keys_define:nn { zref-check / zcheck }
       {
-        thispage .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { thispage } } ,
-        thispage .value_forbidden:n = true ,
-
-        prevpage .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { prevpage } } ,
-        prevpage .value_forbidden:n = true ,
-
-        nextpage .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { nextpage } } ,
-        nextpage .value_forbidden:n = true ,
-
-        facing .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { facing } } ,
-        facing .value_forbidden:n = true ,
-
-        above .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { above } } ,
-        above .value_forbidden:n = true ,
-
-        below .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { below } } ,
-        below .value_forbidden:n = true ,
-
-        pagesbefore .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { pagesbefore } } ,
-        pagesbefore .value_forbidden:n = true ,
-
-        ppbefore .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { ppbefore } } ,
-        ppbefore .value_forbidden:n = true ,
-
-        pagesafter .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { pagesafter } } ,
-        pagesafter .value_forbidden:n = true ,
-
-        ppafter .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { ppafter } } ,
-        ppafter .value_forbidden:n = true ,
-
-        before .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { before } } ,
-        before .value_forbidden:n = true ,
-
-        after .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { after } } ,
-        after .value_forbidden:n = true ,
-
-        thischap .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { thischap } } ,
-        thischap .value_forbidden:n = true ,
-
-        prevchap .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { prevchap } } ,
-        prevchap .value_forbidden:n = true ,
-
-        nextchap .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { nextchap } } ,
-        nextchap .value_forbidden:n = true ,
-
-        chapsbefore .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { chapsbefore } } ,
-        chapsbefore .value_forbidden:n = true ,
-
-        chapsafter .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { chapsafter } } ,
-        chapsafter .value_forbidden:n = true ,
-
-        thissec .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { thissec } } ,
-        thissec .value_forbidden:n = true ,
-
-        prevsec .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { prevsec } } ,
-        prevsec .value_forbidden:n = true ,
-
-        nextsec .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { nextsec } } ,
-        nextsec .value_forbidden:n = true ,
-
-        secsbefore .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { secsbefore } } ,
-        secsbefore .value_forbidden:n = true ,
-
-        secsafter .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { secsafter } } ,
-        secsafter .value_forbidden:n = true ,
-
-        close .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { close } } ,
-        close .value_forbidden:n = true ,
-
-        far .code:n =
-          { \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq { far } } ,
-        far .value_forbidden:n = true ,
-      }
+        #1 .code:n =
+          {
+            \seq_put_right:Nn \l__zrefcheck_zcheck_checks_seq {#1}
+            \seq_if_in:NnF \c__zrefcheck_single_label_checks_seq {#1}
+              { \bool_set_true:N \l__zrefcheck_zcheck_end_label_bool }
+          } ,
+        #1 .value_forbidden:n = true ,
+     }
   }
-\cs_new:Npn \__zrefcheck_run_checks:nnn #1#2#3
+\cs_new_protected:Npn \__zrefcheck_run_checks:nnn #1#2#3
   {
     \group_begin:
-      \tl_map_inline:nn {#2}
+      \seq_map_inline:Nn #2
         {
           \seq_map_inline:Nn #1
             { \__zrefcheck_do_check:nnn {####1} {##1} {#3} }
         }
     \group_end:
   }
-\cs_generate_variant:Nn \__zrefcheck_run_checks:nnn { nnv }
+\cs_generate_variant:Nn \__zrefcheck_run_checks:nnn { nnx }
 \bool_new:N \l__zrefcheck_passedcheck_bool
 \bool_new:N \l__zrefcheck_onpage_bool
 \seq_new:N \c__zrefcheck_onpage_checks_seq
 \seq_set_from_clist:Nn \c__zrefcheck_onpage_checks_seq
   { above , below , before , after }
 \cs_generate_variant:Nn \exp_args:Nnno { Nnoo }
-\cs_new:Npn \__zrefcheck_do_check:nnn #1#2#3
+\cs_new_protected:Npn \__zrefcheck_do_check:nnn #1#2#3
   {
     \group_begin:
       \zref@ifrefundefined {#2}
@@ -603,22 +563,45 @@
               \bool_set_false:N \l__zrefcheck_onpage_bool
               \cs_if_exist:cTF { __zrefcheck_check_ #1 :nnF }
                 {
+                  % ``label beg'' vs ``reference beg''.
                   \use:c { __zrefcheck_check_ #1 :nnF }
                     {#2} {#3}
                     { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
-                  \exp_args:Nnno \use:c { __zrefcheck_check_ #1 :nnF }
-                    {#2} { \__zrefcheck_end_lblfmt:n {#3} }
-                    { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
-                  \zref@ifrefundefined { \__zrefcheck_end_lblfmt:n {#2} }
-                    {}
+                  % ``reference end'' \emph{may} exist or not depending on the
+                  % checks.
+                  \zref@ifrefundefined { \__zrefcheck_end_lblfmt:n {#3} }
                     {
-                      \exp_args:Nno \use:c { __zrefcheck_check_ #1 :nnF }
-                        { \__zrefcheck_end_lblfmt:n {#2} } {#3}
-                        { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
-                      \exp_args:Nnoo \use:c { __zrefcheck_check_ #1 :nnF }
-                        { \__zrefcheck_end_lblfmt:n {#2} }
-                        { \__zrefcheck_end_lblfmt:n {#3} }
+                      % ``label end'' \emph{may} have been created by the
+                      % target commands.
+                      \zref@ifrefundefined { \__zrefcheck_end_lblfmt:n {#2} }
+                        {}
+                        {
+                          % ``label end'' vs ``reference beg''.
+                          \exp_args:Nno \use:c { __zrefcheck_check_ #1 :nnF }
+                            { \__zrefcheck_end_lblfmt:n {#2} } {#3}
+                            { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
+                        }
+                    }
+                    {
+                      % ``label beg'' vs ``reference end''.
+                      \exp_args:Nnno \use:c { __zrefcheck_check_ #1 :nnF }
+                        {#2} { \__zrefcheck_end_lblfmt:n {#3} }
                         { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
+                      % ``label end'' \emph{may} have been created by the
+                      % target commands.
+                      \zref@ifrefundefined { \__zrefcheck_end_lblfmt:n {#2} }
+                        {}
+                        {
+                          % ``label end'' vs ``reference beg''.
+                          \exp_args:Nno \use:c { __zrefcheck_check_ #1 :nnF }
+                            { \__zrefcheck_end_lblfmt:n {#2} } {#3}
+                            { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
+                          % ``label end'' vs ``reference end''.
+                          \exp_args:Nnoo \use:c { __zrefcheck_check_ #1 :nnF }
+                            { \__zrefcheck_end_lblfmt:n {#2} }
+                            { \__zrefcheck_end_lblfmt:n {#3} }
+                            { \bool_set_false:N \l__zrefcheck_passedcheck_bool }
+                        }
                     }
                   \seq_if_in:NnT \c__zrefcheck_onpage_checks_seq {#1}
                     {
@@ -666,7 +649,7 @@
 \int_new:N \l__zrefcheck_ref_int
 \int_new:N \l__zrefcheck_lbl_b_int
 \int_new:N \l__zrefcheck_ref_b_int
-\prg_new_conditional:Npnn \__zrefcheck_check_thispage:nn #1#2 { T , F , TF }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_thispage:nn #1#2 { T , F , TF }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -684,7 +667,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_above:nn #1#2 { F , TF }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_above:nn #1#2 { F , TF }
   {
     \group_begin:
       \__zrefcheck_check_thispage:nnTF {#1} {#2}
@@ -706,7 +689,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_below:nn #1#2 { F , TF }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_below:nn #1#2 { F , TF }
   {
     \__zrefcheck_check_thispage:nnTF {#1} {#2}
       {
@@ -716,7 +699,7 @@
       }
       { \prg_return_false: }
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_before:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_before:nn #1#2 { F }
   {
     \__zrefcheck_check_pagesbefore:nnTF {#1} {#2}
       { \prg_return_true: }
@@ -726,7 +709,7 @@
           { \prg_return_false: }
       }
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_after:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_after:nn #1#2 { F }
   {
     \__zrefcheck_check_pagesafter:nnTF {#1} {#2}
       { \prg_return_true: }
@@ -736,7 +719,7 @@
           { \prg_return_false: }
       }
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_nextpage:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_nextpage:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -754,7 +737,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_prevpage:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_prevpage:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -772,7 +755,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_pagesbefore:nn #1#2 { F , TF }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_pagesbefore:nn #1#2 { F , TF }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -791,7 +774,7 @@
     \group_end:
   }
 \cs_new_eq:NN \__zrefcheck_check_ppbefore:nnF \__zrefcheck_check_pagesbefore:nnF
-\prg_new_conditional:Npnn \__zrefcheck_check_pagesafter:nn #1#2 { F , TF }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_pagesafter:nn #1#2 { F , TF }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -810,7 +793,25 @@
     \group_end:
   }
 \cs_new_eq:NN \__zrefcheck_check_ppafter:nnF \__zrefcheck_check_pagesafter:nnF
-\prg_new_conditional:Npnn \__zrefcheck_check_facing:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_pagegap:nn #1#2 { F }
+  {
+    \group_begin:
+      \bool_set_true:N \l__zrefcheck_integer_bool
+      \zrefcheck_get_asint:nnn {#1} { abspage } { \l__zrefcheck_lbl_int }
+      \zrefcheck_get_asint:nnn {#2} { abspage } { \l__zrefcheck_ref_int }
+      \bool_lazy_and:nnTF
+        { \l__zrefcheck_integer_bool }
+        {
+          \int_compare_p:nNn
+            { \int_abs:n { \l__zrefcheck_lbl_int - \l__zrefcheck_ref_int } } > { 1 } &&
+          ! \int_compare_p:nNn { \l__zrefcheck_lbl_int } = { 0 } &&
+          ! \int_compare_p:nNn { \l__zrefcheck_ref_int } = { 0 }
+        }
+        { \group_insert_after:N \prg_return_true:  }
+        { \group_insert_after:N \prg_return_false: }
+    \group_end:
+  }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_facing:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -839,7 +840,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_close:nn #1#2 { F , TF }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_close:nn #1#2 { F , TF }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -859,13 +860,13 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_far:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_far:nn #1#2 { F }
   {
     \__zrefcheck_check_close:nnTF {#1} {#2}
       { \prg_return_false: }
       { \prg_return_true:  }
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_thischap:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_thischap:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -883,7 +884,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_nextchap:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_nextchap:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -900,7 +901,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_prevchap:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_prevchap:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -918,7 +919,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_chapsafter:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_chapsafter:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -935,7 +936,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_chapsbefore:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_chapsbefore:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -953,7 +954,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_thissec:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_thissec:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -975,7 +976,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_nextsec:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_nextsec:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -996,7 +997,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_prevsec:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_prevsec:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -1018,7 +1019,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_secsafter:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_secsafter:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -1039,7 +1040,7 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
-\prg_new_conditional:Npnn \__zrefcheck_check_secsbefore:nn #1#2 { F }
+\prg_new_protected_conditional:Npnn \__zrefcheck_check_secsbefore:nn #1#2 { F }
   {
     \group_begin:
       \bool_set_true:N \l__zrefcheck_integer_bool
@@ -1061,6 +1062,27 @@
         { \group_insert_after:N \prg_return_false: }
     \group_end:
   }
+\cs_new_protected:Npn \zrefcheck_zcref_beg_label:
+  {
+    \int_gincr:N \g__zrefcheck_id_int
+    \tl_set:Nx \l__zrefcheck_checkbeg_tl
+      { \__zrefcheck_check_lblfmt:n { \g__zrefcheck_id_int } }
+    \zref@labelbylist { \l__zrefcheck_checkbeg_tl } { zrefcheck-check }
+  }
+\cs_new_protected:Npn \zrefcheck_zcref_end_label_maybe:
+  {
+    \bool_if:NT \l__zrefcheck_zcheck_end_label_bool
+      {
+        \zref@labelbylist
+          { \__zrefcheck_end_lblfmt:n { \l__zrefcheck_checkbeg_tl } }
+          { zrefcheck-end }
+      }
+  }
+\cs_new_protected:Npn \zrefcheck_zcref_run_checks_on_labels:n #1
+  {
+    \__zrefcheck_run_checks:nnx
+      { \l__zrefcheck_zcheck_checks_seq } {#1} { \l__zrefcheck_checkbeg_tl }
+  }
 %% 
 %%
 %% End of file `zref-check.sty'.