Fix missing commands

Author: zepinglee

ustcthesis.cls

@@ -1612,13 +1612,16 @@
   { \cs_generate_variant:Nn \tl_set:Nn  { Ne } }
 
 % `\regex_if_match:nnTF` was not available until 2025-05-19.
-\cs_if_exist:NF \regex_if_match:nnTF
-  { \cs_new_protected:Npn \regex_if_match:nnTF { \regex_match:nnTF } }
+\cs_if_exist:NF \regex_if_match:nVTF
+  { \cs_new_protected:Npn \regex_if_match:nVTF { \regex_match:nVTF } }
+
+\cs_if_exist:NF \regex_match:nVTF
+  { \prg_generate_conditional_variant:Nnn \regex_match:Nn { nV } { TF } }
 
 \cs_new:Npn \__ustc_set_date:n #1
   {
     \tl_set:Nx \l_tmpa_tl {#1}
-    \exp_args:NnV \regex_if_match:nnTF { ^ \d + - \d + - \d + $ } \l_tmpa_tl
+    \regex_if_match:nVTF { ^ \d + - \d + - \d + $ } \l_tmpa_tl
       {
         \seq_set_split:NnV \l_tmpa_seq { - } \l_tmpa_tl
         \int_set:Nn \l__ustc_year_int { \seq_item:Nn \l_tmpa_seq { 1 } }
@@ -3155,6 +3158,10 @@
 
 \clist_new:N \g__ustc_bib_files_clist
 
+% \str_set:Ne was not available until 2023-06-05.
+\cs_if_exist:NF \str_set:Ne
+  { \cs_generate_variant:Nn \str_set:Nn  { Ne } }
+
 \NewDocumentCommand \addbibresource { O { } m }
   {
     \tl_if_blank:nF {#1}
@@ -3163,8 +3170,10 @@
       { \msg_error:nn { ustcthesis } { multi-bib-files } }
     \clist_map_inline:nn {#2}
       {
-        \str_set:Nx \l_tmpa_str {##1}
-        \regex_replace_once:nnNF { \. bib $ } { } \l_tmpa_str
+        \str_set:Ne \l_tmpa_str {##1}
+        \str_set:Ne \l_tmpb_str { \str_range:Nnn \l_tmpa_str { -4 } { -1 } }
+        \str_if_eq:VnTF \l_tmpb_str { .bib }
+          { \str_set:Ne \l_tmpa_str { \str_range:Nnn \l_tmpa_str { 1 } { -5 } } }
           { \msg_warning:nn { ustcthesis } { bib-file-extension } }
         \clist_gput_right:NV \g__ustc_bib_files_clist \l_tmpa_str
       }