[CWEB] Add option '+u' for CTANGLE.

Option 'ctangle +u' extends the transliteration mechanism for ``poor
man's UTF-8'. Instead of extending the 'translit' table (or replacing it
with a dynamic data structure), CTANGLE skips all but the last of a
sequence of high-bit bytes representing a single UTF-8 character. Only
the last high-bit byte is used as the index into 'translit' as before.

Example: In ``classic ASCII'', the German word 'grün' was transformed
into 'gruen' with the transliteration '@l fc ue' (from the Western
European codepage ISO/IEC 8859-1; see file cweb_ecma94.w for context).

With UTF-8 encoded input and 'ctangle +u', the first (starter) byte 'c3'
(1100.0011) is skipped and the second (continuing) byte 'bc' is used to
look up the transliteration for 'ü' (latin small letter u with diaeresis),
so '@l bc ue' can be used to get 'gruen' in the C output.

Note that this is not a general UTF-8 transliteration because there are
tons of possible collisions, e.g., '¼' (vulgar fraction one quarter) is
'c2 bc' in UTF-8 and would be transformed into 'ue' as well.

git-svn-id: svn://tug.org/texlive/trunk@64157 c570f23f-e606-0410-a88d-b1316a301751

10 files changed, 162 insertions, 81 deletions

diff --git a/Build/source/texk/web2c/ChangeLog b/Build/source/texk/web2c/ChangeLog
index 3a918c23bac..425cffb4831 100644
--- a/Build/source/texk/web2c/ChangeLog
+++ b/Build/source/texk/web2c/ChangeLog
@@ -1,3 +1,8 @@
+2022-08-21  Andreas Scherer  <https://ascherer.github.io>
+
+	* ctangleboot.cin,
+	* help.h: New option '+u' for CTANGLE.
+
 2022-08-06  Andreas Scherer  <https://ascherer.github.io>
 
 	* weave.ch: Rewrite 'squash' to match description in section 148.
diff --git a/Build/source/texk/web2c/ctangleboot.cin b/Build/source/texk/web2c/ctangleboot.cin
index 9b2c18acc46..cdfa9cbd733 100644
--- a/Build/source/texk/web2c/ctangleboot.cin
+++ b/Build/source/texk/web2c/ctangleboot.cin
@@ -142,6 +142,8 @@
 
 #define translit_length 10 \
 
+#define transliterate_utf_eight flags['u'] \
+
 #define ignore 00
 #define ord 0302
 #define control_text 0303
@@ -274,7 +276,7 @@ extern FILE*active_file;
 extern FILE*check_file;
 
 /*:15*//*116:*/
-#line 506 "cwebdir/ctang-w2c.ch"
+#line 555 "cwebdir/ctang-w2c.ch"
 
 extern char cb_banner[];
 
@@ -357,7 +359,7 @@ static boolean output_defs_seen= false;
 /*:52*//*57:*/
 #line 703 "cwebdir/ctangle.w"
 
-static char translit[128][translit_length];
+static char translit[0200][translit_length];
 
 /*:57*//*62:*/
 #line 779 "cwebdir/ctangle.w"
@@ -512,9 +514,10 @@ cur_out_file= end_output_files= output_files+max_files;
 
 {
 int i;
-for(i= 0;i<128;i++)sprintf(translit[i],"X%02X",(unsigned int)(128+i));
+for(i= 0;i<0200;i++)sprintf(translit[i],"X%02X",(unsigned int)(0200+i));
 }
 
+#line 180 "cwebdir/ctang-w2c.ch"
 /*:58*//*63:*/
 #line 782 "cwebdir/ctangle.w"
 {
@@ -540,7 +543,7 @@ ccode['\'']= ord;
 section_text[0]= ' ';
 
 /*:78*//*117:*/
-#line 509 "cwebdir/ctang-w2c.ch"
+#line 558 "cwebdir/ctang-w2c.ch"
 
 strncpy(cb_banner,banner,max_banner-1);
 
@@ -754,11 +757,11 @@ writeloop:/*50:*/
 if(check_for_change){
 fclose(C_file);C_file= NULL;
 /*106:*/
-#line 389 "cwebdir/ctang-w2c.ch"
+#line 438 "cwebdir/ctang-w2c.ch"
 
 if((C_file= fopen(C_file_name,"r"))!=NULL){
 /*107:*/
-#line 396 "cwebdir/ctang-w2c.ch"
+#line 445 "cwebdir/ctang-w2c.ch"
 
 boolean comparison= false;
 
@@ -767,7 +770,7 @@ fatal(_("! Cannot open output file "),check_file_name);
 
 
 /*108:*/
-#line 410 "cwebdir/ctang-w2c.ch"
+#line 459 "cwebdir/ctang-w2c.ch"
 
 do{
 char x[BUFSIZ],y[BUFSIZ];
@@ -777,17 +780,17 @@ comparison= (x_size==y_size)&&!memcmp(x,y,x_size);
 }while(comparison&&!feof(C_file)&&!feof(check_file));
 
 /*:108*/
-#line 403 "cwebdir/ctang-w2c.ch"
+#line 452 "cwebdir/ctang-w2c.ch"
 
 
 fclose(C_file);C_file= NULL;
 fclose(check_file);check_file= NULL;
 
 /*:107*/
-#line 391 "cwebdir/ctang-w2c.ch"
+#line 440 "cwebdir/ctang-w2c.ch"
 
 /*109:*/
-#line 421 "cwebdir/ctang-w2c.ch"
+#line 470 "cwebdir/ctang-w2c.ch"
 
 if(comparison)
 remove(check_file_name);
@@ -797,7 +800,7 @@ rename(check_file_name,C_file_name);
 }
 
 /*:109*/
-#line 392 "cwebdir/ctang-w2c.ch"
+#line 441 "cwebdir/ctang-w2c.ch"
 
 }else
 rename(check_file_name,C_file_name);
@@ -810,7 +813,7 @@ for(an_output_file= end_output_files;an_output_file> cur_out_file;){
 an_output_file--;
 sprint_section_name(output_file_name,*an_output_file);
 if(check_for_change)/*105:*/
-#line 380 "cwebdir/ctang-w2c.ch"
+#line 429 "cwebdir/ctang-w2c.ch"
 {
 if((C_file= fopen(output_file_name,"a"))==NULL)
 fatal(_("! Cannot open output file "),output_file_name);
@@ -841,14 +844,14 @@ flush_buffer();
 if(check_for_change){
 fclose(C_file);C_file= NULL;
 /*110:*/
-#line 434 "cwebdir/ctang-w2c.ch"
+#line 483 "cwebdir/ctang-w2c.ch"
 
 if(0==strcmp("/dev/stdout",output_file_name))
 /*112:*/
-#line 461 "cwebdir/ctang-w2c.ch"
+#line 510 "cwebdir/ctang-w2c.ch"
 {
 /*115:*/
-#line 492 "cwebdir/ctang-w2c.ch"
+#line 541 "cwebdir/ctang-w2c.ch"
 
 char in_buf[BUFSIZ+1];
 int in_size;
@@ -858,7 +861,7 @@ fatal(_("! Cannot open output file "),check_file_name);
 
 
 /*:115*/
-#line 462 "cwebdir/ctang-w2c.ch"
+#line 511 "cwebdir/ctang-w2c.ch"
 
 do{
 in_size= fread(in_buf,sizeof(char),BUFSIZ,check_file);
@@ -867,7 +870,7 @@ fprintf(stdout,"%s",in_buf);
 }while(!feof(check_file));
 fclose(check_file);check_file= NULL;
 /*111:*/
-#line 451 "cwebdir/ctang-w2c.ch"
+#line 500 "cwebdir/ctang-w2c.ch"
 
 if(comparison)
 remove(check_file_name);
@@ -877,19 +880,19 @@ rename(check_file_name,output_file_name);
 }
 
 /*:111*/
-#line 469 "cwebdir/ctang-w2c.ch"
+#line 518 "cwebdir/ctang-w2c.ch"
 
 }
 
 /*:112*/
-#line 436 "cwebdir/ctang-w2c.ch"
+#line 485 "cwebdir/ctang-w2c.ch"
 
 else if(0==strcmp("/dev/stderr",output_file_name))
 /*113:*/
-#line 474 "cwebdir/ctang-w2c.ch"
+#line 523 "cwebdir/ctang-w2c.ch"
 {
 /*115:*/
-#line 492 "cwebdir/ctang-w2c.ch"
+#line 541 "cwebdir/ctang-w2c.ch"
 
 char in_buf[BUFSIZ+1];
 int in_size;
@@ -899,7 +902,7 @@ fatal(_("! Cannot open output file "),check_file_name);
 
 
 /*:115*/
-#line 475 "cwebdir/ctang-w2c.ch"
+#line 524 "cwebdir/ctang-w2c.ch"
 
 do{
 in_size= fread(in_buf,sizeof(char),BUFSIZ,check_file);
@@ -908,7 +911,7 @@ fprintf(stderr,"%s",in_buf);
 }while(!feof(check_file));
 fclose(check_file);check_file= NULL;
 /*111:*/
-#line 451 "cwebdir/ctang-w2c.ch"
+#line 500 "cwebdir/ctang-w2c.ch"
 
 if(comparison)
 remove(check_file_name);
@@ -918,20 +921,20 @@ rename(check_file_name,output_file_name);
 }
 
 /*:111*/
-#line 482 "cwebdir/ctang-w2c.ch"
+#line 531 "cwebdir/ctang-w2c.ch"
 
 }
 
 /*:113*/
-#line 438 "cwebdir/ctang-w2c.ch"
+#line 487 "cwebdir/ctang-w2c.ch"
 
 else if(0==strcmp("/dev/null",output_file_name))
 /*114:*/
-#line 487 "cwebdir/ctang-w2c.ch"
+#line 536 "cwebdir/ctang-w2c.ch"
 {
 boolean comparison= true;
 /*111:*/
-#line 451 "cwebdir/ctang-w2c.ch"
+#line 500 "cwebdir/ctang-w2c.ch"
 
 if(comparison)
 remove(check_file_name);
@@ -941,17 +944,17 @@ rename(check_file_name,output_file_name);
 }
 
 /*:111*/
-#line 489 "cwebdir/ctang-w2c.ch"
+#line 538 "cwebdir/ctang-w2c.ch"
 
 }
 
 /*:114*/
-#line 440 "cwebdir/ctang-w2c.ch"
+#line 489 "cwebdir/ctang-w2c.ch"
 
 else{
 if((C_file= fopen(output_file_name,"r"))!=NULL){
 /*107:*/
-#line 396 "cwebdir/ctang-w2c.ch"
+#line 445 "cwebdir/ctang-w2c.ch"
 
 boolean comparison= false;
 
@@ -960,7 +963,7 @@ fatal(_("! Cannot open output file "),check_file_name);
 
 
 /*108:*/
-#line 410 "cwebdir/ctang-w2c.ch"
+#line 459 "cwebdir/ctang-w2c.ch"
 
 do{
 char x[BUFSIZ],y[BUFSIZ];
@@ -970,17 +973,17 @@ comparison= (x_size==y_size)&&!memcmp(x,y,x_size);
 }while(comparison&&!feof(C_file)&&!feof(check_file));
 
 /*:108*/
-#line 403 "cwebdir/ctang-w2c.ch"
+#line 452 "cwebdir/ctang-w2c.ch"
 
 
 fclose(C_file);C_file= NULL;
 fclose(check_file);check_file= NULL;
 
 /*:107*/
-#line 443 "cwebdir/ctang-w2c.ch"
+#line 492 "cwebdir/ctang-w2c.ch"
 
 /*111:*/
-#line 451 "cwebdir/ctang-w2c.ch"
+#line 500 "cwebdir/ctang-w2c.ch"
 
 if(comparison)
 remove(check_file_name);
@@ -990,7 +993,7 @@ rename(check_file_name,output_file_name);
 }
 
 /*:111*/
-#line 444 "cwebdir/ctang-w2c.ch"
+#line 493 "cwebdir/ctang-w2c.ch"
 
 }else
 rename(check_file_name,output_file_name);
@@ -1074,15 +1077,25 @@ case'\n':if(protect&&out_state!=verbatim)C_putc(' ');
 if(protect||out_state==verbatim)C_putc('\\');
 flush_buffer();if(out_state!=verbatim)out_state= normal;break;
 /*59:*/
-#line 712 "cwebdir/ctangle.w"
+#line 206 "cwebdir/ctang-w2c.ch"
 
+#line 713 "cwebdir/ctangle.w"
 case identifier:
 if(out_state==num_or_id)C_putc(' ');
 for(j= (cur_val+name_dir)->byte_start,k= (cur_val+name_dir+1)->byte_start;
 j<k;j++)
-if((eight_bits)(*j)<0200)C_putc(*j);
+#line 214 "cwebdir/ctang-w2c.ch"
+if(ishigh(*j)){
 
-else C_printf("%s",translit[(eight_bits)(*j)-0200]);
+if(transliterate_utf_eight){
+if((eight_bits)(*j)>=0360)j+= 3;
+else if((eight_bits)(*j)>=0340)j+= 2;
+else if((eight_bits)(*j)>=0300)j+= 1;
+}
+C_printf("%s",translit[(eight_bits)(*j)-0200]);
+}
+else C_putc(*j);
+#line 720 "cwebdir/ctangle.w"
 out_state= num_or_id;break;
 
 /*:59*/
@@ -1188,7 +1201,7 @@ if(loc> limit){
 if(is_long_comment){
 if(get_line())return comment_continues= true;
 else{
-#line 180 "cwebdir/ctang-w2c.ch"
+#line 229 "cwebdir/ctang-w2c.ch"
 err_print(_("! Input ended in mid-comment"));
 #line 853 "cwebdir/ctangle.w"
 
@@ -1203,7 +1216,7 @@ loc++;return comment_continues= false;
 }
 if(c=='@'){
 if(ccode[(eight_bits)*loc]==new_section){
-#line 186 "cwebdir/ctang-w2c.ch"
+#line 235 "cwebdir/ctang-w2c.ch"
 err_print(_("! Section name ended in mid-comment"));loc--;
 #line 866 "cwebdir/ctangle.w"
 
@@ -1311,13 +1324,13 @@ delim= *loc++;*++id_loc= delim;
 while(true){
 if(loc>=limit){
 if(*(limit-1)!='\\'){
-#line 192 "cwebdir/ctang-w2c.ch"
+#line 241 "cwebdir/ctang-w2c.ch"
 err_print(_("! String didn't end"));loc= limit;break;
 #line 1016 "cwebdir/ctangle.w"
 
 }
 if(get_line()==false){
-#line 198 "cwebdir/ctang-w2c.ch"
+#line 247 "cwebdir/ctang-w2c.ch"
 err_print(_("! Input ended in middle of string"));loc= buffer;break;
 #line 1020 "cwebdir/ctangle.w"
 
@@ -1337,7 +1350,7 @@ c= (eight_bits)*loc++;
 if(++id_loc<=section_text_end)*id_loc= (char)c;
 }
 if(id_loc>=section_text_end){
-#line 204 "cwebdir/ctang-w2c.ch"
+#line 253 "cwebdir/ctang-w2c.ch"
 fputs(_("\n! String too long: "),stdout);
 #line 1038 "cwebdir/ctangle.w"
 
@@ -1371,14 +1384,14 @@ else if(c=='@')/*75:*/
 
 switch(c= ccode[(eight_bits)*loc++]){
 case ignore:continue;
-#line 210 "cwebdir/ctang-w2c.ch"
+#line 259 "cwebdir/ctang-w2c.ch"
 case translit_code:err_print(_("! Use @l in limbo only"));continue;
 #line 1053 "cwebdir/ctangle.w"
 
 case control_text:while((c= skip_ahead())=='@');
 
 if(*(loc-1)!='>')
-#line 216 "cwebdir/ctang-w2c.ch"
+#line 265 "cwebdir/ctang-w2c.ch"
 err_print(_("! Double @ should be used in control text"));
 #line 1058 "cwebdir/ctangle.w"
 
@@ -1394,7 +1407,7 @@ char*k= section_text;
 
 while(true){
 if(loc> limit&&get_line()==false){
-#line 234 "cwebdir/ctang-w2c.ch"
+#line 283 "cwebdir/ctang-w2c.ch"
 err_print(_("! Input ended in section name"));
 #line 1120 "cwebdir/ctangle.w"
 
@@ -1410,13 +1423,13 @@ if(c=='>'){
 loc+= 2;break;
 }
 if(ccode[(eight_bits)c]==new_section){
-#line 246 "cwebdir/ctang-w2c.ch"
+#line 295 "cwebdir/ctang-w2c.ch"
 err_print(_("! Section name didn't end"));break;
 #line 1147 "cwebdir/ctangle.w"
 
 }
 if(ccode[(eight_bits)c]==section_name){
-#line 252 "cwebdir/ctang-w2c.ch"
+#line 301 "cwebdir/ctang-w2c.ch"
 err_print(_("! Nesting of section names not allowed"));break;
 #line 1151 "cwebdir/ctangle.w"
 
@@ -1434,7 +1447,7 @@ c= (eight_bits)' ';if(*(k-1)==' ')k--;
 *k= (char)c;
 }
 if(k>=section_text_end){
-#line 240 "cwebdir/ctang-w2c.ch"
+#line 289 "cwebdir/ctang-w2c.ch"
 fputs(_("\n! Section name too long: "),stdout);
 #line 1133 "cwebdir/ctangle.w"
 
@@ -1482,7 +1495,7 @@ case string:/*81:*/
 
 id_first= loc++;*(limit+1)= '@';*(limit+2)= '>';
 while(*loc!='@'||*(loc+1)!='>')loc++;
-#line 258 "cwebdir/ctang-w2c.ch"
+#line 307 "cwebdir/ctang-w2c.ch"
 if(loc>=limit)err_print(_("! Verbatim string didn't end"));
 #line 1165 "cwebdir/ctangle.w"
 
@@ -1501,7 +1514,7 @@ if(*++loc=='\'')loc++;
 while(*loc!='\''){
 if(*loc=='@'){
 if(*(loc+1)!='@')
-#line 222 "cwebdir/ctang-w2c.ch"
+#line 271 "cwebdir/ctang-w2c.ch"
 err_print(_("! Double @ should be used in ASCII constant"));
 #line 1082 "cwebdir/ctangle.w"
 
@@ -1509,7 +1522,7 @@ else loc++;
 }
 loc++;
 if(loc> limit){
-#line 228 "cwebdir/ctang-w2c.ch"
+#line 277 "cwebdir/ctang-w2c.ch"
 err_print(_("! String didn't end"));loc= limit-1;break;
 #line 1088 "cwebdir/ctangle.w"
 
@@ -1615,7 +1628,7 @@ char*try_loc= loc;
 while(*try_loc==' '&&try_loc<limit)try_loc++;
 if(*try_loc=='+'&&try_loc<limit)try_loc++;
 while(*try_loc==' '&&try_loc<limit)try_loc++;
-#line 294 "cwebdir/ctang-w2c.ch"
+#line 343 "cwebdir/ctang-w2c.ch"
 if(*try_loc=='=')err_print(_("! Missing `@ ' before a named section"));
 #line 1291 "cwebdir/ctangle.w"
 
@@ -1651,7 +1664,7 @@ store_id(a);
 
 }
 break;
-#line 282 "cwebdir/ctang-w2c.ch"
+#line 331 "cwebdir/ctang-w2c.ch"
 case output_defs_code:if(t!=section_name)err_print(_("! Misplaced @h"));
 #line 1263 "cwebdir/ctangle.w"
 
@@ -1690,7 +1703,7 @@ app_repl(a);
 while(id_first<id_loc){
 if(*id_first=='@'){
 if(*(id_first+1)=='@')id_first++;
-#line 300 "cwebdir/ctang-w2c.ch"
+#line 349 "cwebdir/ctang-w2c.ch"
 else err_print(_("! Double @ should be used in string"));
 #line 1308 "cwebdir/ctangle.w"
 
@@ -1744,7 +1757,7 @@ break;
 case'\\':c= '\\';break;
 case'\'':c= '\'';break;
 case'\"':c= '\"';break;
-#line 306 "cwebdir/ctang-w2c.ch"
+#line 355 "cwebdir/ctang-w2c.ch"
 default:err_print(_("! Unrecognized escape sequence"));
 #line 1357 "cwebdir/ctangle.w"
 
@@ -1764,7 +1777,7 @@ app_repl(constant);
 break;
 case definition:case format_code:case begin_C:if(t!=section_name)goto done;
 else{
-#line 288 "cwebdir/ctang-w2c.ch"
+#line 337 "cwebdir/ctang-w2c.ch"
 err_print(_("! @d, @f and @c are ignored in C text"));continue;
 #line 1281 "cwebdir/ctangle.w"
 
@@ -1780,7 +1793,7 @@ break;
 default:app_repl(a);
 }
 done:next_control= (eight_bits)a;
-#line 276 "cwebdir/ctang-w2c.ch"
+#line 325 "cwebdir/ctang-w2c.ch"
 if(text_ptr> text_info_end)overflow(_("text"));
 #line 1216 "cwebdir/ctangle.w"
 cur_text= text_ptr;(++text_ptr)->tok_start= tok_ptr;
@@ -1819,7 +1832,7 @@ if(next_control==definition){
 
 while((next_control= get_next())=='\n');
 if(next_control!=identifier){
-#line 312 "cwebdir/ctang-w2c.ch"
+#line 361 "cwebdir/ctang-w2c.ch"
 err_print(_("! Definition flushed, must start with identifier"));
 #line 1430 "cwebdir/ctangle.w"
 
@@ -1930,7 +1943,7 @@ while(xisspace(*loc)&&loc<limit)loc++;
 loc+= 3;
 if(loc> limit||!xisxdigit(*(loc-3))||!xisxdigit(*(loc-2))
 ||(*(loc-3)>='0'&&*(loc-3)<='7')||!xisspace(*(loc-1)))
-#line 332 "cwebdir/ctang-w2c.ch"
+#line 381 "cwebdir/ctang-w2c.ch"
 err_print(_("! Improper hex number following @l"));
 #line 1529 "cwebdir/ctangle.w"
 
@@ -1940,9 +1953,9 @@ char*beg;
 sscanf(loc-3,"%x",&i);
 while(xisspace(*loc)&&loc<limit)loc++;
 beg= loc;
-while(loc<limit&&(xisalpha(*loc)||xisdigit(*loc)||*loc=='_'))loc++;
+while(loc<limit&&(xisalpha(*loc)||xisdigit(*loc)||isxalpha(*loc)))loc++;
 if(loc-beg>=translit_length)
-#line 338 "cwebdir/ctang-w2c.ch"
+#line 387 "cwebdir/ctang-w2c.ch"
 err_print(_("! Replacement string in @l too long"));
 #line 1539 "cwebdir/ctangle.w"
 
@@ -1959,12 +1972,12 @@ case format_code:case'@':break;
 case control_text:if(c=='q'||c=='Q'){
 while((c= (char)skip_ahead())=='@');
 if(*(loc-1)!='>')
-#line 318 "cwebdir/ctang-w2c.ch"
+#line 367 "cwebdir/ctang-w2c.ch"
 err_print(_("! Double @ should be used in control text"));
 #line 1511 "cwebdir/ctangle.w"
 
 break;
-#line 325 "cwebdir/ctang-w2c.ch"
+#line 374 "cwebdir/ctang-w2c.ch"
 }/* otherwise fall through */
 default:err_print(_("! Double @ should be used in limbo"));
 #line 1515 "cwebdir/ctangle.w"
@@ -1979,7 +1992,7 @@ default:err_print(_("! Double @ should be used in limbo"));
 
 void
 print_stats(void){
-#line 351 "cwebdir/ctang-w2c.ch"
+#line 400 "cwebdir/ctang-w2c.ch"
 puts(_("\nMemory usage statistics:"));
 printf(_("%td names (out of %ld)\n"),
 (ptrdiff_t)(name_ptr-name_dir),(long)max_names);
@@ -1992,5 +2005,5 @@ printf(_("%td tokens (out of %ld)\n"),
 (ptrdiff_t)(tok_ptr-tok_mem),(long)max_toks);
 }
 
-#line 364 "cwebdir/ctang-w2c.ch"
+#line 413 "cwebdir/ctang-w2c.ch"
 /*:103*/
diff --git a/Build/source/texk/web2c/cwebdir/ChangeLog b/Build/source/texk/web2c/cwebdir/ChangeLog
index 7aa44a8a43c..23200f88c01 100644
--- a/Build/source/texk/web2c/cwebdir/ChangeLog
+++ b/Build/source/texk/web2c/cwebdir/ChangeLog
@@ -1,3 +1,10 @@
+2022-08-21  Andreas Scherer  <https://ascherer.github.io>
+
+	* ctang-w2c.ch,
+	* ctangle.c,
+	* ctangle.w,
+	* cwebman-w2c.ch: New option '+u' for CTANGLE.
+
 2022-07-02  Andreas Scherer  <https://ascherer.github.io>
 
 	* cwebmac.tex,
diff --git a/Build/source/texk/web2c/cwebdir/ctang-w2c.ch b/Build/source/texk/web2c/cwebdir/ctang-w2c.ch
index 9b115568f4f..d12ffd85066 100644
--- a/Build/source/texk/web2c/cwebdir/ctang-w2c.ch
+++ b/Build/source/texk/web2c/cwebdir/ctang-w2c.ch
@@ -175,6 +175,55 @@ if (check_for_change)
 @z
 
 @x
+@ @<Case of an identifier@>=@t\1\quad@>
+@y
+@ Nowadays, most computer files are encoded in some form of ``Unicode''. A very
+convenient special case is ``UTF-8'', a variable-length multi-byte encoding. In
+order to avoid major surgery for the transliteration feature---as tempting as
+the extended notation \.{@@l c3bc ue} might be---, \.{CTANGLE}
+accepts the \.{+u} option to activate a ``poor man's UTF-8'' mechanism. The
+first in a sequence of up to four high-bit bytes (amounting to more than
+$2^{20}$~possible character representations) determines the number of bytes
+used to represent the next character. Instead of extending the |translit| table
+to this multi-byte scenario, we simply strip all but the last byte and use this
+as the transliteration index.
+
+% Exercise 11.6 from the TeXbook:
+\def\frac#1/#2{\leavevmode\kern.1em\raise.5ex\hbox{\the\scriptfont0 #1}
+  \kern-.1em/\kern-.15em\lower.25ex\hbox{\the\scriptfont0 #2}}
+
+\&{Example:} While in ``classic ASCII'' the German word {\it gr\"un\/} could be
+treated with transliteration \.{@@l fc ue} (from codepage ISO/IEC~8859-1) to
+get \.{gruen} as suggested above, in UTF-8 you'd be advised to use \.{@@l bc
+ue} instead, because character {\it \"u\/} (latin small letter u with
+diaeresis) is encoded as the two-byte sequence \.{c3 bc}, indicated by the
+initial three bits of byte \.{c3} (\.{1100 0011}). Note that this simple
+approach leads to the collision with character $\frac1/4$ (vulgar fraction one
+quarter) with its two-byte encoding \.{c2 bc}.
+
+@d transliterate_utf_eight flags['u']
+
+@<Case of an identifier@>=@t\1\quad@>
+@z
+
+@x
+    if ((eight_bits)(*j)<0200) C_putc(*j);
+@^high-bit character handling@>
+    else C_printf("%s",translit[(eight_bits)(*j)-0200]);
+@y
+    if (ishigh(*j)) {
+@^high-bit character handling@>
+      if (transliterate_utf_eight) {
+        if ((eight_bits)(*j)>=0360) j+=3;
+        else if ((eight_bits)(*j)>=0340) j+=2;
+        else if ((eight_bits)(*j)>=0300) j+=1;
+      }
+      C_printf("%s",translit[(eight_bits)(*j)-0200]);
+    }
+    else C_putc(*j);
+@z
+
+@x
           err_print("! Input ended in mid-comment");
 @y
           err_print(_("! Input ended in mid-comment"));
diff --git a/Build/source/texk/web2c/cwebdir/ctangle.c b/Build/source/texk/web2c/cwebdir/ctangle.c
index 262469d6119..8f6b14e260c 100644
--- a/Build/source/texk/web2c/cwebdir/ctangle.c
+++ b/Build/source/texk/web2c/cwebdir/ctangle.c
@@ -330,7 +330,7 @@ static boolean output_defs_seen= false;
 /*:52*//*57:*/
 #line 703 "ctangle.w"
 
-static char translit[128][translit_length];
+static char translit[0200][translit_length];
 
 /*:57*//*62:*/
 #line 779 "ctangle.w"
@@ -484,7 +484,7 @@ cur_out_file= end_output_files= output_files+max_files;
 
 {
 int i;
-for(i= 0;i<128;i++)sprintf(translit[i],"X%02X",(unsigned int)(128+i));
+for(i= 0;i<0200;i++)sprintf(translit[i],"X%02X",(unsigned int)(0200+i));
 }
 
 /*:58*//*63:*/
@@ -1607,7 +1607,7 @@ char*beg;
 sscanf(loc-3,"%x",&i);
 while(xisspace(*loc)&&loc<limit)loc++;
 beg= loc;
-while(loc<limit&&(xisalpha(*loc)||xisdigit(*loc)||*loc=='_'))loc++;
+while(loc<limit&&(xisalpha(*loc)||xisdigit(*loc)||isxalpha(*loc)))loc++;
 if(loc-beg>=translit_length)
 err_print("! Replacement string in @l too long");
 
diff --git a/Build/source/texk/web2c/cwebdir/ctangle.w b/Build/source/texk/web2c/cwebdir/ctangle.w
index 0c372e59ed8..af4f4e92811 100644
--- a/Build/source/texk/web2c/cwebdir/ctangle.w
+++ b/Build/source/texk/web2c/cwebdir/ctangle.w
@@ -690,8 +690,8 @@ case period_ast: C_putc('.');@+C_putc('*'); out_state=normal; break;
 case minus_gt_ast: C_putc('-');@+C_putc('>');@+C_putc('*'); out_state=normal;
     break;
 
-@ When an identifier is output to the \CEE/ file, characters in the
-range 128--255 must be changed into something else, so the \CEE/
+@ When an identifier is output to the \CEE/ file, characters in the range
+128--255 (|0200|--|0377|) must be changed into something else, so the \CEE/
 compiler won't complain.  By default, \.{CTANGLE} converts the
 character with code $16 x+y$ to the three characters `\.X$xy$', but
 a different transliteration table can be specified.  Thus a German
@@ -701,12 +701,12 @@ This makes debugging a lot less confusing.
 @d translit_length 10
 
 @<Private...@>=
-static char translit[128][translit_length];
+static char translit[0200][translit_length];
 
 @ @<Set init...@>=
 {
   int i;
-  for (i=0;i<128;i++) sprintf(translit[i],"X%02X",(unsigned int)(128+i));
+  for (i=0;i<0200;i++) sprintf(translit[i],"X%02X",(unsigned int)(0200+i));
 }
 
 @ @<Case of an identifier@>=@t\1\quad@>
@@ -1533,7 +1533,7 @@ skip_limbo(void)
     sscanf(loc-3,"%x",&i);
     while(xisspace(*loc)&&loc<limit) loc++;
     beg=loc;
-    while(loc<limit&&(xisalpha(*loc)||xisdigit(*loc)||*loc=='_')) loc++;
+    while(loc<limit&&(xisalpha(*loc)||xisdigit(*loc)||isxalpha(*loc))) loc++;
     if (loc-beg>=translit_length)
       err_print("! Replacement string in @@l too long");
 @.Replacement string in @@l...@>
diff --git a/Build/source/texk/web2c/cwebdir/cwebman-w2c.ch b/Build/source/texk/web2c/cwebdir/cwebman-w2c.ch
index fb8421349a3..73a907deb5e 100644
--- a/Build/source/texk/web2c/cwebdir/cwebman-w2c.ch
+++ b/Build/source/texk/web2c/cwebdir/cwebman-w2c.ch
@@ -182,13 +182,13 @@ more logical than indenting them.) (Has no effect on \.{CTANGLE}.)
 \hfil\vskip\normallineskip
 \option l This option takes the string of characters to its right as its
 argument to switch between different user languages and macro packages.
-For example, if you call \.{CWEAVE} with the `\.{+ld}' (or `\.{-ld}') option,
-the German \.{CWEB} macros \.{dcwebmac.tex} will be loaded in the first line
-of output instead of the English ones. (Off by default.) (Has no effect on
-\.{CTANGLE}.)
+(Off by default.) (Has no effect on \.{CTANGLE}.)
 \hfil\vskip\normallineskip
 \option o Separate declarations and the first statement in a function block.
-(On by default.) (Has no effect on\break\hbox{}\qquad\.{CTANGLE}.)}
+(On by default.) (Has no effect on \.{CTANGLE}.)
+\hfil\vskip\normallineskip
+\option u Transliteration of UTF-8 multi-byte characters.
+(Off by default.) (Has no effect on \.{CWEAVE}.)}
 
 \yskip
 @z
diff --git a/Build/source/texk/web2c/help.h b/Build/source/texk/web2c/help.h
index 668d3f9f98c..df52bf7679b 100644
--- a/Build/source/texk/web2c/help.h
+++ b/Build/source/texk/web2c/help.h
@@ -65,6 +65,7 @@ const_string CTANGLEHELP[] = {
     "-dN         set 'kpathsea_debug' to N (0..127)",
     "+k          keep separators in numeric literals in the output",
     "+s          print usage statistics",
+    "+u          transliterate UTF-8 characters in C code",
     "--help      display this help and exit",
     "--version   output version information and exit",
     NULL
diff --git a/Build/source/texk/web2c/man/ChangeLog b/Build/source/texk/web2c/man/ChangeLog
index 95a11e7d444..b8a2a842f05 100644
--- a/Build/source/texk/web2c/man/ChangeLog
+++ b/Build/source/texk/web2c/man/ChangeLog
@@ -1,3 +1,7 @@
+2022-08-21  Andreas Scherer  <https://ascherer.github.io>
+
+	* cweb.man: New option '+u' for CTANGLE.
+
 2022-06-05  Andreas Scherer  <https://ascherer.github.io>
 
 	* ctwill.man: CWEB 4.8 release.
diff --git a/Build/source/texk/web2c/man/cweb.man b/Build/source/texk/web2c/man/cweb.man
index fd481db48d4..b1d051551fe 100644
--- a/Build/source/texk/web2c/man/cweb.man
+++ b/Build/source/texk/web2c/man/cweb.man
@@ -14,7 +14,7 @@
 . ftr VB CB
 . ftr VBI CBI
 .\}
-.TH "CWEB" "1" "July 27, 2021" "Web2c @VERSION@" "General Commands Manual"
+.TH "CWEB" "1" "August 20, 2022" "Web2c @VERSION@" "General Commands Manual"
 .hy
 .SH NAME
 .PP
@@ -70,7 +70,7 @@ There are, however, a few differences worth noting:
 .IP \[bu] 2
 Options \f[B]--help\f[R], \f[B]--quiet\f[R], \f[B]--verbose\f[R],
 \f[B]--version\f[R], and flags \f[B]+c\f[R], \f[B]-i\f[R], \f[B]-o\f[R],
-and \f[B]+lX\f[R] are new in CWEBbin and TeX\ Live.
+\f[B]+u\f[R], and \f[B]+lX\f[R] are new in CWEBbin and TeX\ Live.
 .IP \[bu] 2
 Option \f[B]+lX\f[R] is accompanied by several wrapper files for
 \f[B]cwebmac.tex\f[R] with translated captions for German
@@ -120,6 +120,8 @@ The first batch of options are common to both \f[B]ctangle\f[R] and
 There is one other option applicable to \f[B]ctangle\f[R] only:
 .IP \[bu] 2
 \f[B]+k\f[R]: keep separators in numeric literals in the output
+.IP \[bu] 2
+\f[B]+u\f[R]: transliterate UTF-8 charcters in C code
 .PP
 There are seven other options applicable to \f[B]cweave\f[R] only:
 .IP \[bu] 2