summaryrefslogtreecommitdiff
path: root/macros/latex-dev/base/ltfssaxes.dtx
blob: d8e4286b786e7d63541f64bcf1cec30c05f8091e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
% \iffalse meta-comment
%
% Copyright (C) 2019-2020
% The LaTeX3 Project and any individual authors listed elsewhere
% in this file.
%
% This file is part of the LaTeX base system.
% -------------------------------------------
%
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
%    https://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008 or later.
%
% This file has the LPPL maintenance status "maintained".
%
% The list of all files belonging to the LaTeX base distribution is
% given in the file `manifest.txt'. See also `legal.txt' for additional
% information.
%
% The list of derived (unpacked) files belonging to the distribution
% and covered by LPPL is defined by the unpacking scripts (with
% extension .ins) which are part of the distribution.
%
% \fi
% \iffalse
%%% From File: ltfssaxes.dtx
%% Copyright (C) 1999-2020 Frank Mittelbach
%
%<*driver>
% \fi
%
%
\ProvidesFile{ltfssaxes.dtx}
             [2020/08/21 v1.0g LaTeX Kernel (NFSS Axes handing)]
% \iffalse
\documentclass{ltxdoc}
\begin{document}
\DocInput{ltfssaxes.dtx}
\end{document}
%</driver>
% \fi
%
%
%
%
% \GetFileInfo{ltfssaxes.dtx}
% \title{A new font selection scheme for \TeX{} macro packages\\
%        (Axes Handling)\thanks
%       {This file has version number
%       \fileversion\ dated \filedate}}
%
% \author{Frank Mittelbach}
%
% \MaintainedByLaTeXTeam{latex}
% \maketitle
%
% This file contains the implementation for handling extra axes
% splitting the series and the values into sub-categories.  selection
% commands. See other parts of the \LaTeX\ distribution, or \emph{The
% \LaTeX\ Companion} for higher level documentation of the
% \LaTeX\ Font Selection Scheme.
%
%
%
% \StopEventually{}
%
% Everything in the this file got introduced 2020/02/02, so we do a
% single rollback (for now).
%    \begin{macrocode}
%<*2ekernel>
%</2ekernel>
%<*2ekernel|latexrelease>
%<latexrelease>\IncludeInRelease{2020/02/02}%
%<latexrelease>   {\DeclareFontSeriesChangeRule}{Series change rules}%
%    \end{macrocode}
%
%
%
% \section{Changing the font series}
%
% In the original NFSS implementation the series was a single
% attribute stored in \cs{f@series} and so one always had to specify
% both weight and width together. This means it was impossible to
% typeset, a paragraph in a condensed font and inside have a few words
% in bold weight (but still condensed) without doing this manually by
% requesting \verb=\fontseries{bc}\selectfont=.
%
% The new implementation now works differently by looking both at the
% current value of \cs{f@series} and the requested new series and out
% of that combination selects a resulting series value. Thus, if the
% current series is \texttt{c} and we ask for \texttt{b} we  now get
% \texttt{bc}.
%
% This is done by consulting a simple lookup table. This table is
% configurable (though most likely that flexibility will seldom of
% ever be needed) Adding or changing entries in this table are done
% with \cs{DeclareFontSeriesChangeRule}.
%
% \subsection{The series lookup table}
%
%
%  \begin{macro}{\DeclareFontSeriesChangeRule}
%    The \cs{DeclareFontSeriesChangeRule} defines entries in a simple
%    database (implemented as a set of commands) that define mappings
%    between from an existing series and requested new series and maps
%    that to  a result series (and additionally offers an alternative
%    if the desired one is not existing):
%    \begin{itemize}
%    \item[\texttt{\#1}] current \cs{f@series}
%    \item[\texttt{\#2}] requested new series
%    \item[\texttt{\#3}] result (if that exist for the given font family
%    \item[\texttt{\#4}] alternative result (if \texttt{\#3} does not exist)
%    \end{itemize}
%    If an \texttt{.fd} file has its own substitution rules then
%    \texttt{\#3} exist and thus \texttt{\#4} is not applied.
%
%    If there is no matching database entry or if neither the result
%    nor the alternate result exist in the font family the requested
%    new series is used (which then may trigger substitutions later on.
%    \begin{macrocode}
\def\DeclareFontSeriesChangeRule#1#2#3#4{%
  \@namedef{series@#1@#2}{{#3}{#4}}}
%    \end{macrocode}
%  \end{macro}
%
% \subsection{Mapping rules for series changes}
%
% The rules set up use explicit series values not \cs{..default}
% indirections; my current feeling is that this is in fact better.
%
% With 9 weights and 9 width classes this table is getting a bit large
% in the end (324 entries) but on the other hand it doesn't change and
% accessing speed and it is fast this way.
%
% We could alternatively split the axis and maintain weight and width
% separately, but that would take more processing time and would not
% allow for setting up explicit exceptions nicely (not sure that this
% would ever get used though).
%
% Design considerations for mapping entries:
% \begin{itemize}
% \item
%
%    We make \texttt{m} to reset both weight and width (as this is
%    how it always worked). To reset just the width \texttt{?m} is
%    provided and to reset just the weight \texttt{m?}.
%
% \item
%
%   We do support ``\texttt{m}\textit{width}'' and
%    ``\textit{weight}\texttt{m}'', e.g., \texttt{mec} to mean ``go to
%    medium weight and extra-condensed width''. At the end of the
%    process we automatically drop any leftover \texttt{m} in the
%    series name (unless it is just a single \texttt{m}).
%
%
% \item
%
%    If there is no table entry then the target series is used
%    unconditionally. This means that any request to set both weight
%    and width (e.g. \texttt{bx} or \texttt{ulc}) needs no table
%    entries.
%    For that reason there are no entries which have a weight+width as
%    request (i.e., second argument).
%
%    In particular this is also true for cases involving \texttt{m},
%    e.g., \texttt{bm} (bold medium width) which automatially gets
%    reduced result in \texttt{b} or \texttt{mc} (medium weight
%    condensed) which becomes \texttt{c} as a result.
%
% \item
%
%    Only a few entries have ``alterative'' values and perhaps most of
%    them should get dropped. Or maybe not \ldots{} needs some thought
%    perhaps.
%
%    The idea is that you don't want the normal substitution to kick
%    in because that would reset the shape first and it may be better
%    to stay with \texttt{b} when a change to \texttt{c} is requested
%    and \texttt{bc} doesn't exist, than to go to first change the
%    shape to \texttt{n} and then find that \texttt{bc/n} doesn't
%    exist either and thus ending up wth \texttt{m/n}.
%
% \item
%
%    Also: while I did set up all nine standard weight values from
%    \texttt{ul} to \texttt{ub} I only bothered to provide entries for
%    \texttt{ec},  \texttt{sc}, \texttt{c} and \texttt{x}, because other levels of
%    compression/expansion are not in any real fonts that I know.
%
%    Could and perhaps should be eventually extended to cover the
%    whole set.
%
% \end{itemize}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {bc}{b}{bc}{}
\DeclareFontSeriesChangeRule {bc}{c}{bc}{}
\DeclareFontSeriesChangeRule {bc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {bc}{ec}{bec} {bc}
\DeclareFontSeriesChangeRule {bc}{el}{elc}{}
\DeclareFontSeriesChangeRule {bc}{l}{lc}{}
\DeclareFontSeriesChangeRule {bc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {bc}{sc}{bsc} {bc}
\DeclareFontSeriesChangeRule {bc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {bc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {bc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {bc}{x}{bx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {bx}{b}{bx}{}
\DeclareFontSeriesChangeRule {bx}{c}  {bc}  {bx}	%<-----
\DeclareFontSeriesChangeRule {bx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {bx}{ec}  {bec}  {bx}	%<-----
\DeclareFontSeriesChangeRule {bx}{el}{elx}{}
\DeclareFontSeriesChangeRule {bx}{l}{lx}{}
\DeclareFontSeriesChangeRule {bx}{sb} {sbx} {}
\DeclareFontSeriesChangeRule {bx}{sc}  {bsc}  {bx}	%<-----
\DeclareFontSeriesChangeRule {bx}{sl}{slx}  {}
\DeclareFontSeriesChangeRule {bx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {bx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {bx}{x}{bx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {b}{bx} {bx}  {b}		%<-----
\DeclareFontSeriesChangeRule {b}{c}  {bc}  {b}		%<-----
\DeclareFontSeriesChangeRule {b}{ec}  {bec}  {b}	%<-----
\DeclareFontSeriesChangeRule {b}{sb} {sb}  {b}		%<-----
\DeclareFontSeriesChangeRule {b}{sc}  {bsc}  {b}	%<-----
\DeclareFontSeriesChangeRule {b}{x}  {bx}  {b}		%<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {c}{bx} {bx}  {b} 		%<-----
\DeclareFontSeriesChangeRule {c}{b}{bc}{}
\DeclareFontSeriesChangeRule {c}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {c}{el}{elc}{}
\DeclareFontSeriesChangeRule {c}{l}{lc}{}
\DeclareFontSeriesChangeRule {c}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {c}{sl}{slc}{}
\DeclareFontSeriesChangeRule {c}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {c}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {c}{x}{x}{m}               %<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ebc}{b}{bc}{}
\DeclareFontSeriesChangeRule {ebc}{c}{ebc}{}
\DeclareFontSeriesChangeRule {ebc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {ebc}{ec}{ebec}{ebc}
\DeclareFontSeriesChangeRule {ebc}{el}{elc}{}
\DeclareFontSeriesChangeRule {ebc}{l}{lc}{}
\DeclareFontSeriesChangeRule {ebc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {ebc}{sc}{ebsc}{ebc}
\DeclareFontSeriesChangeRule {ebc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {ebc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {ebc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {ebc}{x}{ebx}{}
%    \end{macrocode}
%
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ec}{bx} {bx}  {b} 	%<-----
\DeclareFontSeriesChangeRule {ec}{b}{bec}{}
\DeclareFontSeriesChangeRule {ec}{eb}{ebec}{}
\DeclareFontSeriesChangeRule {ec}{el}{elec}{}
\DeclareFontSeriesChangeRule {ec}{l}{lec}{}
\DeclareFontSeriesChangeRule {ec}{sb}{sbec}{}
\DeclareFontSeriesChangeRule {ec}{sl}{slec}{}
\DeclareFontSeriesChangeRule {ec}{ub}{ubec}{}
\DeclareFontSeriesChangeRule {ec}{ul}{ulec}{}
\DeclareFontSeriesChangeRule {ec}{x}{x}{m}              %<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {sc}{bx} {bx}  {b} 	%<-----
\DeclareFontSeriesChangeRule {sc}{b}{bsc}{}
\DeclareFontSeriesChangeRule {sc}{eb}{ebsc}{}
\DeclareFontSeriesChangeRule {sc}{el}{elsc}{}
\DeclareFontSeriesChangeRule {sc}{l}{lsc}{}
\DeclareFontSeriesChangeRule {sc}{sb}{sbsc}{}
\DeclareFontSeriesChangeRule {sc}{sl}{slsc}{}
\DeclareFontSeriesChangeRule {sc}{ub}{ubsc}{}
\DeclareFontSeriesChangeRule {sc}{ul}{ulsc}{}
\DeclareFontSeriesChangeRule {sc}{x}{x}{m}              %<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ebx}{b}{bx}{}
\DeclareFontSeriesChangeRule {ebx}{c}{ebc}{}
\DeclareFontSeriesChangeRule {ebx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {ebx}{ec}{ebec}{}
\DeclareFontSeriesChangeRule {ebx}{el}{elx}{}
\DeclareFontSeriesChangeRule {ebx}{l}{lx}{}
\DeclareFontSeriesChangeRule {ebx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {ebx}{sc}{ebsc}{}
\DeclareFontSeriesChangeRule {ebx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {ebx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {ebx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {ebx}{x}{ebx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {eb}{c}{ebc}{}
\DeclareFontSeriesChangeRule {eb}{ec}{ebec}{}
\DeclareFontSeriesChangeRule {eb}{sc}{ebsc}{}
\DeclareFontSeriesChangeRule {eb}{x}{ebx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {elc}{b}{bc}{}
\DeclareFontSeriesChangeRule {elc}{c}{elc}{}
\DeclareFontSeriesChangeRule {elc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {elc}{ec}{elec}{}
\DeclareFontSeriesChangeRule {elc}{el}{elc}{}
\DeclareFontSeriesChangeRule {elc}{l}{lc}{}
\DeclareFontSeriesChangeRule {elc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {elc}{sc}{elsc}{}
\DeclareFontSeriesChangeRule {elc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {elc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {elc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {elc}{x}{elx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {elx}{b}{bx}{}
\DeclareFontSeriesChangeRule {elx}{c}{elc}{}
\DeclareFontSeriesChangeRule {elx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {elx}{ec}{elec}{}
\DeclareFontSeriesChangeRule {elx}{el}{elx}{}
\DeclareFontSeriesChangeRule {elx}{l}{lx}{}
\DeclareFontSeriesChangeRule {elx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {elx}{sc}{elsc}{}
\DeclareFontSeriesChangeRule {elx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {elx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {elx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {elx}{x}{elx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {el}{c}{elc}{}
\DeclareFontSeriesChangeRule {el}{ec}{elec}{}
\DeclareFontSeriesChangeRule {el}{sc}{elsc}{}
\DeclareFontSeriesChangeRule {el}{x}{elx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {lc}{b}{bc}{}
\DeclareFontSeriesChangeRule {lc}{c}{lc}{}
\DeclareFontSeriesChangeRule {lc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {lc}{ec}{lec}{}
\DeclareFontSeriesChangeRule {lc}{el}{elc}{}
\DeclareFontSeriesChangeRule {lc}{l}{lc}{}
\DeclareFontSeriesChangeRule {lc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {lc}{sc}{lsc}{}
\DeclareFontSeriesChangeRule {lc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {lc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {lc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {lc}{x}{lx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {lx}{b}{bx}{}
\DeclareFontSeriesChangeRule {lx}{c}{lc}{}
\DeclareFontSeriesChangeRule {lx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {lx}{ec}{lec}{}
\DeclareFontSeriesChangeRule {lx}{el}{elx}{}
\DeclareFontSeriesChangeRule {lx}{l}{lx}{}
\DeclareFontSeriesChangeRule {lx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {lx}{sc}{lsc}{}
\DeclareFontSeriesChangeRule {lx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {lx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {lx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {lx}{x}{lx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {l}{bx} {bx}  {b}		%<-----
\DeclareFontSeriesChangeRule {l}{b}  {b}   {bx}		%<-----
\DeclareFontSeriesChangeRule {l}{c}  {lc}  {l}  % ?	%<-----
\DeclareFontSeriesChangeRule {l}{ec}  {lec}  {l}  % ?	%<-----
\DeclareFontSeriesChangeRule {l}{sb} {sb}  {b}  % ?	%<-----
\DeclareFontSeriesChangeRule {l}{sc}  {lsc}  {l}  % ?	%<-----
\DeclareFontSeriesChangeRule {l}{x}  {lx}  {l}  % ?	%<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {m}{bx} {bx} {b}	  	%<-----
\DeclareFontSeriesChangeRule {m}{b}  {b}  {bx}		%<-----
\DeclareFontSeriesChangeRule {m}{c}  {c}  {m}		%<-----
\DeclareFontSeriesChangeRule {m}{ec}  {ec}  {m}		%<-----
\DeclareFontSeriesChangeRule {m}{l}  {l}  {m}		%<-----
\DeclareFontSeriesChangeRule {m}{sb} {sb} {b}		%<-----
\DeclareFontSeriesChangeRule {m}{sc}  {sc}  {m}		%<-----
\DeclareFontSeriesChangeRule {m}{x}  {x}  {m}		%<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {sbc}{b}{bc}{}
\DeclareFontSeriesChangeRule {sbc}{c}{sbc}{}
\DeclareFontSeriesChangeRule {sbc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {sbc}{ec}{sbec}{sbc}
\DeclareFontSeriesChangeRule {sbc}{el}{elc}{}
\DeclareFontSeriesChangeRule {sbc}{l}{lc}{}
\DeclareFontSeriesChangeRule {sbc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {sbc}{sc}{sbsc}{sbc}
\DeclareFontSeriesChangeRule {sbc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {sbc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {sbc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {sbc}{x}{sbx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {sbx}{b}{bx}{}
\DeclareFontSeriesChangeRule {sbx}{c}{sbc}{}
\DeclareFontSeriesChangeRule {sbx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {sbx}{ec}{sbec}{}
\DeclareFontSeriesChangeRule {sbx}{el}{elx}{}
\DeclareFontSeriesChangeRule {sbx}{l}{lx}{}
\DeclareFontSeriesChangeRule {sbx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {sbx}{sc}{sbsc}{}
\DeclareFontSeriesChangeRule {sbx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {sbx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {sbx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {sbx}{x}{sbx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {sb}{c}  {sbc} {bc} %?	%<-----
\DeclareFontSeriesChangeRule {sb}{ec}  {sbec} {sbc} %?	%<-----
\DeclareFontSeriesChangeRule {sb}{sc}  {sbsc} {sbc} %?	%<-----
\DeclareFontSeriesChangeRule {sb}{x}  {sbx} {bx} %?	%<-----
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {slc}{b}{bc}{}
\DeclareFontSeriesChangeRule {slc}{c}{slc}{}
\DeclareFontSeriesChangeRule {slc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {slc}{ec}{slec}{}
\DeclareFontSeriesChangeRule {slc}{el}{elc}{}
\DeclareFontSeriesChangeRule {slc}{l}{lc}{}
\DeclareFontSeriesChangeRule {slc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {slc}{sc}{slsc}{}
\DeclareFontSeriesChangeRule {slc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {slc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {slc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {slc}{x}{slx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {slx}{b}{bx}{}
\DeclareFontSeriesChangeRule {slx}{c}{slc}{}
\DeclareFontSeriesChangeRule {slx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {slx}{ec}{slec}{}
\DeclareFontSeriesChangeRule {slx}{el}{elx}{}
\DeclareFontSeriesChangeRule {slx}{l}{lx}{}
\DeclareFontSeriesChangeRule {slx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {slx}{sc}{slsc}{}
\DeclareFontSeriesChangeRule {slx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {slx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {slx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {slx}{x}{slx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {sl}{c}{slc}{}
\DeclareFontSeriesChangeRule {sl}{ec}{slec}{}
\DeclareFontSeriesChangeRule {sl}{sc}{slsc}{}
\DeclareFontSeriesChangeRule {sl}{x}{slx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ubc}{b}{bc}{}
\DeclareFontSeriesChangeRule {ubc}{c}{ubc}{}
\DeclareFontSeriesChangeRule {ubc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {ubc}{ec}{ubec}{}
\DeclareFontSeriesChangeRule {ubc}{el}{elc}{}
\DeclareFontSeriesChangeRule {ubc}{l}{lc}{}
\DeclareFontSeriesChangeRule {ubc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {ubc}{sc}{ubsc}{}
\DeclareFontSeriesChangeRule {ubc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {ubc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {ubc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {ubc}{x}{ubx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ubx}{b}{bx}{}
\DeclareFontSeriesChangeRule {ubx}{c}{ubc}{}
\DeclareFontSeriesChangeRule {ubx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {ubx}{ec}{ubec}{}
\DeclareFontSeriesChangeRule {ubx}{el}{elx}{}
\DeclareFontSeriesChangeRule {ubx}{l}{lx}{}
\DeclareFontSeriesChangeRule {ubx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {ubx}{sc}{ubsc}{}
\DeclareFontSeriesChangeRule {ubx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {ubx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {ubx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {ubx}{x}{ubx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ub}{c}{ubc}{}
\DeclareFontSeriesChangeRule {ub}{ec}{ubec}{}
\DeclareFontSeriesChangeRule {ub}{sc}{ubsc}{}
\DeclareFontSeriesChangeRule {ub}{x}{ubx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ulc}{b}{bc}{}
\DeclareFontSeriesChangeRule {ulc}{c}{ulc}{}
\DeclareFontSeriesChangeRule {ulc}{eb}{ebc}{}
\DeclareFontSeriesChangeRule {ulc}{ec}{ulec}{ulc}
\DeclareFontSeriesChangeRule {ulc}{el}{elc}{}
\DeclareFontSeriesChangeRule {ulc}{l}{lc}{}
\DeclareFontSeriesChangeRule {ulc}{sb}{sbc}{}
\DeclareFontSeriesChangeRule {ulc}{sc}{ulsc}{ulc}
\DeclareFontSeriesChangeRule {ulc}{sl}{slc}{}
\DeclareFontSeriesChangeRule {ulc}{ub}{ubc}{}
\DeclareFontSeriesChangeRule {ulc}{ul}{ulc}{}
\DeclareFontSeriesChangeRule {ulc}{x}{ulx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ulx}{b}{bx}{}
\DeclareFontSeriesChangeRule {ulx}{c}{ulc}{}
\DeclareFontSeriesChangeRule {ulx}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {ulx}{ec}{ulec}{}
\DeclareFontSeriesChangeRule {ulx}{el}{elx}{}
\DeclareFontSeriesChangeRule {ulx}{l}{lx}{}
\DeclareFontSeriesChangeRule {ulx}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {ulx}{sc}{ulsc}{}
\DeclareFontSeriesChangeRule {ulx}{sl}{slx}{}
\DeclareFontSeriesChangeRule {ulx}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {ulx}{ul}{ulx}{}
\DeclareFontSeriesChangeRule {ulx}{x}{ulx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {ul}{c}{ulc}{}
\DeclareFontSeriesChangeRule {ul}{ec}{ulec}{}
\DeclareFontSeriesChangeRule {ul}{sc}{ulsc}{}
\DeclareFontSeriesChangeRule {ul}{x}{ulx}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {x}{b}{bx}{}
\DeclareFontSeriesChangeRule {x}{c}{c}{}
\DeclareFontSeriesChangeRule {x}{eb}{ebx}{}
\DeclareFontSeriesChangeRule {x}{ec}{ec}{}
\DeclareFontSeriesChangeRule {x}{el}{elx}{}
\DeclareFontSeriesChangeRule {x}{l}{lx}{}
\DeclareFontSeriesChangeRule {x}{sb}{sbx}{}
\DeclareFontSeriesChangeRule {x}{sc}{sc}{}
\DeclareFontSeriesChangeRule {x}{sl}{slx}{}
\DeclareFontSeriesChangeRule {x}{ub}{ubx}{}
\DeclareFontSeriesChangeRule {x}{ul}{ulx}{}
%    \end{macrocode}
%
%
%    Special rules for \texttt{lm} etc.\ aren't needed because if the
%    target \texttt{lm} is request it will used if there is no rule
%    and that id then reduced to \texttt{l}
%    automatically. Same for \texttt{mc} and friends. Only \texttt{?m}
%    and \texttt{m?} need rules.
%
%    So here are the special rules for \texttt{m?}:
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {bc}{m?}{c}{}
\DeclareFontSeriesChangeRule {bec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {bsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {bx}{m?}{x}{}
\DeclareFontSeriesChangeRule {b}{m?}{m}{}
\DeclareFontSeriesChangeRule {c}{m?}{c}{}
\DeclareFontSeriesChangeRule {ebc}{m?}{c}{}
\DeclareFontSeriesChangeRule {ebec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {ebsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {ebx}{m?}{x}{}
\DeclareFontSeriesChangeRule {eb}{m?}{m}{}
\DeclareFontSeriesChangeRule {ec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {elc}{m?}{c}{}
\DeclareFontSeriesChangeRule {elec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {elsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {elx}{m?}{x}{}
\DeclareFontSeriesChangeRule {el}{m?}{m}{}
\DeclareFontSeriesChangeRule {lc}{m?}{c}{}
\DeclareFontSeriesChangeRule {lec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {lsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {lx}{m?}{x}{}
\DeclareFontSeriesChangeRule {l}{m?}{m}{}
\DeclareFontSeriesChangeRule {m}{m?}{m}{}
\DeclareFontSeriesChangeRule {sbc}{m?}{c}{}
\DeclareFontSeriesChangeRule {sbec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {sbsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {sbx}{m?}{x}{}
\DeclareFontSeriesChangeRule {sb}{m?}{m}{}
\DeclareFontSeriesChangeRule {sc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {slc}{m?}{c}{}
\DeclareFontSeriesChangeRule {slec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {slsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {slx}{m?}{x}{}
\DeclareFontSeriesChangeRule {sl}{m?}{m}{}
\DeclareFontSeriesChangeRule {ubc}{m?}{c}{}
\DeclareFontSeriesChangeRule {ubec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {ubsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {ubx}{m?}{x}{}
\DeclareFontSeriesChangeRule {ub}{m?}{ub}{}
\DeclareFontSeriesChangeRule {ulc}{m?}{c}{}
\DeclareFontSeriesChangeRule {ulec}{m?}{ec}{}
\DeclareFontSeriesChangeRule {ulsc}{m?}{sc}{}
\DeclareFontSeriesChangeRule {ulx}{m?}{x}{}
\DeclareFontSeriesChangeRule {ul}{m?}{m}{}
\DeclareFontSeriesChangeRule {x}{m?}{x}{}
%    \end{macrocode}
%
%    And there the special rules for \texttt{?m}:
%    \begin{macrocode}
\DeclareFontSeriesChangeRule {bc}{?m}{b}{}
\DeclareFontSeriesChangeRule {bec}{?m}{b}{}
\DeclareFontSeriesChangeRule {bsc}{?m}{b}{}
\DeclareFontSeriesChangeRule {bsc}{?m}{b}{}
\DeclareFontSeriesChangeRule {bx}{?m}{b}{}
\DeclareFontSeriesChangeRule {b}{?m}{b}{}
\DeclareFontSeriesChangeRule {c}{?m}{m}{}
\DeclareFontSeriesChangeRule {ebc}{?m}{eb}{}
\DeclareFontSeriesChangeRule {ebec}{?m}{eb}{}
\DeclareFontSeriesChangeRule {ebsc}{?m}{eb}{}
\DeclareFontSeriesChangeRule {ebsc}{?m}{eb}{}
\DeclareFontSeriesChangeRule {ebx}{?m}{eb}{}
\DeclareFontSeriesChangeRule {eb}{?m}{eb}{}
\DeclareFontSeriesChangeRule {ec}{?m}{m}{}
\DeclareFontSeriesChangeRule {elc}{?m}{el}{}
\DeclareFontSeriesChangeRule {elec}{?m}{el}{}
\DeclareFontSeriesChangeRule {elsc}{?m}{el}{}
\DeclareFontSeriesChangeRule {elsc}{?m}{el}{}
\DeclareFontSeriesChangeRule {elx}{?m}{el}{}
\DeclareFontSeriesChangeRule {el}{?m}{el}{}
\DeclareFontSeriesChangeRule {lc}{?m}{l}{}
\DeclareFontSeriesChangeRule {lec}{?m}{l}{}
\DeclareFontSeriesChangeRule {lsc}{?m}{l}{}
\DeclareFontSeriesChangeRule {lsc}{?m}{l}{}
\DeclareFontSeriesChangeRule {lx}{?m}{l}{}
\DeclareFontSeriesChangeRule {l}{?m}{l}{}
\DeclareFontSeriesChangeRule {m}{?m}{m}{}
\DeclareFontSeriesChangeRule {sbc}{?m}{sb}{}
\DeclareFontSeriesChangeRule {sbec}{?m}{sb}{}
\DeclareFontSeriesChangeRule {sbsc}{?m}{sb}{}
\DeclareFontSeriesChangeRule {sbsc}{?m}{sb}{}
\DeclareFontSeriesChangeRule {sbx}{?m}{sb}{}
\DeclareFontSeriesChangeRule {sb}{?m}{sb}{}
\DeclareFontSeriesChangeRule {sc}{?m}{m}{}
\DeclareFontSeriesChangeRule {sc}{?m}{m}{}
\DeclareFontSeriesChangeRule {slc}{?m}{sl}{}
\DeclareFontSeriesChangeRule {slec}{?m}{sl}{}
\DeclareFontSeriesChangeRule {slsc}{?m}{sl}{}
\DeclareFontSeriesChangeRule {slsc}{?m}{sl}{}
\DeclareFontSeriesChangeRule {slx}{?m}{sl}{}
\DeclareFontSeriesChangeRule {sl}{?m}{sl}{}
\DeclareFontSeriesChangeRule {ubc}{?m}{ub}{}
\DeclareFontSeriesChangeRule {ubec}{?m}{ub}{}
\DeclareFontSeriesChangeRule {ubsc}{?m}{ub}{}
\DeclareFontSeriesChangeRule {ubsc}{?m}{ub}{}
\DeclareFontSeriesChangeRule {ubx}{?m}{ub}{}
\DeclareFontSeriesChangeRule {ub}{?m}{m}{}
\DeclareFontSeriesChangeRule {ulc}{?m}{ul}{}
\DeclareFontSeriesChangeRule {ulec}{?m}{ul}{}
\DeclareFontSeriesChangeRule {ulsc}{?m}{ul}{}
\DeclareFontSeriesChangeRule {ulsc}{?m}{ul}{}
\DeclareFontSeriesChangeRule {ulx}{?m}{ul}{}
\DeclareFontSeriesChangeRule {ul}{?m}{ul}{}
\DeclareFontSeriesChangeRule {x}{?m}{m}{}
%    \end{macrocode}
%
%


% \subsection{Changing to a new series}
%
%

%  \begin{macro}{\if@forced@series}
%    If the series gets forced we need to know that fact later on.
% \changes{v1.0c}{2020/02/10}{Switch \cs{if@forced@series} added}
%    \begin{macrocode}
\newif\if@forced@series
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\fontseriesforce}
%    To change unconditionally to a new series you can use
%    \cs{fontseriesforce}. Of course, if the series doesn't exist for
%    the current family substitution still happens, but there is not
%    dependency on the current series.
% \changes{v1.0c}{2020/02/10}{Switch \cs{if@forced@series} added}
%    \begin{macrocode}
\DeclareRobustCommand\fontseriesforce[1]{\@forced@seriestrue\edef\f@series{#1}}
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\fontseries}
%    The \cs{fontseries} command takes one argument which is the requested new
%    font series. In the orginal implementation  it simply saved the
%    expanded value in \cs{f@series}. Now we do a bit more processing
%    and look up the final value in the font series data base. This is
%    done by \cs{merge@font@series}.
% \changes{v1.0c}{2020/02/10}{Switch \cs{if@forced@series} added}
%    \begin{macrocode}
\DeclareRobustCommand\fontseries[1]{\@forced@seriesfalse\merge@font@series{#1}}
%    \end{macrocode}
%  \end{macro}


%  \begin{macro}{\merge@font@series}
%    We look up the data base value by expanding the right command
%    twice. If no such value exist then the result will be \cs{relax}
%    otherwise it will be the two brace groups: the desired result and
%    the alternate result. The first case means that the third
%    argument to \cs{merge@font@series} will be empty.
%    \begin{macrocode}
\def\merge@font@series#1{%
  \expandafter\expandafter\expandafter
  \merge@font@series@
    \csname series@\f@series @#1\endcsname
    {#1}%
    \@nil
}
%    \end{macrocode}
%  \end{macro}



%  \begin{macro}{\merge@font@series@}
%    This now defines the new \cs{f@series}:
%    \begin{macrocode}
\def\merge@font@series@#1#2#3\@nil{%
%    \end{macrocode}
%    If the third argument is empty there is no database entry for the
%    combination and the second argument holds the new series so we
%    return that.
%
%    Originally the test was simply \verb=\ifx!#3!= but that actually
%    dies if \texttt{\#3} starts with a conditional and in the
%    definition of \cs{AmSfont} that is actually the case.
%    \begin{macrocode}
%\ifcat\expandafter X\detokenize{#1}X%
  \def\reserved@a{#3}%
  \ifx\reserved@a\@empty
    \set@target@series{#2}%
  \else
%    \end{macrocode}
%    Otherwise we check if the desired result for the series
%    (\texttt{\#1}) exists for the font family and the current shape.
%    As the \texttt{.fd} is perhaps not loaded yet, we first
%    have to do that, otherwise the test would fail even if the face
%    is actually available.
%    \begin{macrocode}
    \maybe@load@fontshape
    \edef\reserved@a{\f@encoding /\f@family /#1/\f@shape}%
     \ifcsname \reserved@a \endcsname
%    \end{macrocode}
%     If the desired result is available then we use that. However, we
%    do need some post-processing because we need to drop surplus
%    \texttt{m}s due to the way naming convention was designed in the
%    '90s (sigh).
%    \begin{macrocode}
       \set@target@series{#1}%
%    \end{macrocode}
%    If not, then we try the alternate result (\texttt{\#2}).
%    \begin{macrocode}
    \else
       \ifcsname \f@encoding /\f@family /#2/\f@shape \endcsname
%    \end{macrocode}
%    If the alternate result exist we use that and also issue a
%    warning (or rather a log entry) that we didn't managed to change
%    to the desired font.
%    \begin{macrocode}
         \set@target@series{#2}%
         \@font@shape@subst@warning
%    \end{macrocode}
%    If that doesn't exist either, then we use the requested series unmodified
%    (again with a warning).
%    \begin{macrocode}
       \else
         \set@target@series{#3}%
         \@font@shape@subst@warning
       \fi
    \fi
  \fi
}
%    \end{macrocode}
%    It is possible that the previous font and the new one are
%    actually identical (and the font was not found because it still
%    needs loading) in which case a warning  would look rather odd. So
%    we make a quick check for that (which is the reason why we defined
%    \cs{@reserveda} above.
%    \begin{macrocode}
\def\@font@shape@subst@warning{%
   \edef\reserved@b{\curr@fontshape}%
   \ifx\reserved@a\reserved@b \else
     \@font@warning{Font shape `\reserved@a' undefined\MessageBreak
                    using `\reserved@b' instead}%
   \fi
}
%    \end{macrocode}
%  \end{macro}
%
%
%
%
%  \begin{macro}{\maybe@load@fontshape}
%    A small helper that we use a couple of times: try loading a
%    fontshape (in a group because \cs{try@load@fontshape} normalizes
%    catcodes).
%    \begin{macrocode}
\def\maybe@load@fontshape{\begingroup\try@load@fontshape\endgroup}
%    \end{macrocode}
%  \end{macro}
%
%
%
%  \begin{macro}{\set@target@series}
%
%    Finally the code for normalizing the \cs{f@series} value.
%
%    The combined series value determined by the mapping may still
%    contain an \texttt{m} that we have to remove (as the \texttt{.fd}
%    files use \texttt{c} not \texttt{mc} to denote a medium weight
%    condensed series, etc.). We do this in all branches above because a user
%    might have written
%\begin{verbatim}
\DeclareFontSeriesChangeRule {m}{sc}{msc}{mc}
%\end{verbatim}
%    instead of using \texttt{sc} and \texttt{c} as needed in the
%    \texttt{.fd} file.
%    \begin{macrocode}
\def\set@target@series#1{%
%    \end{macrocode}
%    We need to \cs{edef} the argument first in case it starts with a
%    conditional. Then we check (and perhaps drop) an ``m'' from the
%    value andassign the result to \cs{f@series}.
% \changes{v1.0d}{2020/02/27}{Drop ``m'' only in a specific set of values (gh/293)}
%    \begin{macrocode}
    \edef\f@series{#1}%
    \series@maybe@drop@one@m\f@series\f@series
}
%    \end{macrocode}
%  \end{macro}
%    
%  \begin{macro}{\series@maybe@drop@one@m}
%    If the series value is in NFSS notation then it should not
%    contain any ``m'' unless it is just an ``m'' by it own. So we
%    need to drop surplus ``m''s. But we better don't do this for full
%    names, such as ``\texttt{semibold}'' as used by
%    \texttt{autoinst}, for example. So we test against the possible
%    explicit values that should drop an ``m''.
%    After that we assign the result to \verb=#2= for further use.
% \changes{v1.0d}{2020/02/27}{Drop ``m'' in certain values from a
%    fixed list (gh/293)}
%    \begin{macrocode}
\def\series@maybe@drop@one@m#1{%
  \expandafter\series@maybe@drop@one@m@x\expandafter{#1}}
%    \end{macrocode}
%    
%    \begin{macrocode}

\def\series@maybe@drop@one@m@x#1#2{%
%    \end{macrocode}
%    The code below is an inline version of the \cs{in@} macro without
%    the group, so that it works in \cs{accent}.
%    \begin{macrocode}
  \def\in@@##1,#1,{}%
  \series@check@toks\expandafter{\in@@
    ,ulm,elm,lm,slm,mm,sbm,bm,ebm,ubm,muc,mec,mc,msc,msx,mx,mex,mux,{}{},#1,}%
  \edef\in@@{\the\series@check@toks}%
  \ifx\in@@\@empty
%    \end{macrocode}
%    The default definition for \cs{bfdefault} etc is actually
%    \texttt{b\cs{@empty}} so that we can detect if the user has
%    changed the default. However that means a) the above test will
%    definitely fail (maybe something to change) and b) we better use
%    \cs{edef} on the next line to get rid of it as otherwise the test
%    against \verb=#2= (e.g. \cs{bfdef@ult}) will fail in other places.
% \changes{v1.0e}{2020/05/19}{Need to use \cs{edef} (gh/336)}
%    \begin{macrocode}
    \edef#2{#1}%
  \else
    \edef#2{\expandafter\series@drop@one@m #1m\series@drop@one@m}%
  \fi
}
%    \end{macrocode}
%    As a precaution we use a private toks register not \cs{toks@} as
%    that is no longer hidden inside the group.
%    \begin{macrocode}
\newtoks\series@check@toks
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\series@drop@one@m}
%    Drop up to two \texttt{m}s but keep one if that makes the series
%    value empty. Actually, with the current implementation we know
%    that there is at least one in the series value itself and we
%    added one after it, so all we have to do is now returning
%    \verb=#1#2= and dropping the rest.
%    \begin{macrocode}
\def\series@drop@one@m#1m#2m#3\series@drop@one@m{%
%  \ifx\relax#1#2\relax m\else#1#2\fi
   #1#2%
}
%    \end{macrocode}
%  \end{macro}



% \section{Changing the shape}
%
%    Shapes are also split in two axes (though it could be more if
%    that is desirable), essentially building in an ``sc''
%    axis).
%
%
%
%  \begin{macro}{\DeclareFontShapeChangeRule}
%    The database for shapes is done in exactly the same way, only
%    that it is much smaller and we usually have no alternative shape
%    (or rather it is empty thus not used).
%    \begin{macrocode}
\def\DeclareFontShapeChangeRule #1#2#3#4{%
  \@namedef{shape@#1@#2}{{#3}{#4}}}
%    \end{macrocode}
%  \end{macro}
%
%
%    There is kind of the same problem with returning back from
%    \texttt{sc} to normal. It sort of needs its own letter.  In
%    \texttt{fontspec} this was solved by the first time \cs{upshape} changes
%    \texttt{it} or \texttt{sl} back (so only \texttt{sc} remains) and
%    second time it changes then \texttt{sc} back to normal.  Maybe
%    that's not a bad way to handle it, but decided for a slightly
%    different approach: \texttt{n} always returns to ``normal'', ie
%    resets everything and \texttt{up} changes italic or slanted to
%    upright and \texttt{ulc} undoes small caps.
%
%    So we now offer \cs{normalshape} (using \cs{shapedefault} which is normally the same as
%    calling both \cs{ulcshape} and \cs{upshape}, only more efficient.
%
%
%  \begin{macro}{\ulcshape}
%  \begin{macro}{\textulc}
%  \begin{macro}{\ulcdefault}
%    To request going back to upper/lowercase we need a new
%    command. It uses \texttt{ulc} as shape name but this shape is
%    virtual, i.e., it doesn't exist as a real shape, it is only used
%    as part of the database table entries and thus only appears in
%    the second argument there (but not in the first).
%    \begin{macrocode}
\DeclareRobustCommand\ulcshape
        {\not@math@alphabet\ulcshape\relax
         \fontshape\ulcdefault\selectfont}
\let\ulcdefault\@undefined      % for rollback
\newcommand\ulcdefault{ulc}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%  \begin{macro}{\swshape}
%  \begin{macro}{\textsw}
%  \begin{macro}{\swdefault}
%    New command to select a swash shape.  The standard rules put this
%    in the same category as italics or slanted, i.e., if you ask for
%    it then italics are undone. One could provide more complicated
%    rules so that \texttt{it} + \texttt{sw} becomes \texttt{swit} but
%    given that there are only very few fonts that have swash letters
%    that level of flexibility (these days) would be just resulting in
%    a lot of combinations that do not exist.
%    \begin{macrocode}
\DeclareRobustCommand\swshape
        {\not@math@alphabet\swshape\relax
         \fontshape\swdefault\selectfont}
\let\swdefault\@undefined      % for rollback
\newcommand\swdefault{sw}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%
%
%  \begin{macro}{\sscshape}
%  \begin{macro}{\textssc}
%  \begin{macro}{\sscdefault}
%    New command to select spaced small capitals. This is only here
%    because \texttt{fontaxes} offered it. There isn't a single free
%    font that supports it. However, some commercial ones do, so we
%    offer it so that at some point \texttt{fontaxes} could be
%    retired.
%
%    So far there aren't any rules for it---probably there should be
%    some putting it in the same category as \texttt{sc}.
%    \begin{macrocode}
\DeclareRobustCommand\sscshape
        {\not@math@alphabet\sscshape\relax
         \fontshape\sscdefault\selectfont}
\let\sscdefault\@undefined      % for rollback
\newcommand\sscdefault{ssc}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%
%
% \subsection{Mapping rules for shape combinations}
%
%    Many of the entries are commented out as we will get that result
%    without any entry.
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {n}{n}   {n}   {}
\DeclareFontShapeChangeRule {n}{it}  {it}  {sl}
\DeclareFontShapeChangeRule {n}{sl}  {sl}  {it}
%\DeclareFontShapeChangeRule {n}{sw}  {sw}  {}
%\DeclareFontShapeChangeRule {n}{sc}  {sc}  {}
\DeclareFontShapeChangeRule {n}{ulc} {n}   {}
\DeclareFontShapeChangeRule {n}{up} {n}    {}
%    \end{macrocode}
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {it}{n}   {n}     {}
%\DeclareFontShapeChangeRule {it}{it}  {it}    {}
\DeclareFontShapeChangeRule {it}{sl}  {sl}    {it}
%\DeclareFontShapeChangeRule {it}{sw}  {sw}    {}
%    \end{macrocode}
%    If neither \texttt{scit} nor \texttt{scsl} exist then \texttt{sc}
%    will be used as a fallback albeit with a log entry, so except for
%    the latter there will be no change for CM or Latin Modern fonts.
%    \begin{macrocode}
\DeclareFontShapeChangeRule {it}{sc}  {scit}  {scsl}
\DeclareFontShapeChangeRule {it}{ulc} {it}    {}
\DeclareFontShapeChangeRule {it}{up} {n}      {}
%    \end{macrocode}
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {sl}{n}   {n}     {}
\DeclareFontShapeChangeRule {sl}{it}  {it}    {sl}
%\DeclareFontShapeChangeRule {sl}{sl}  {sl}    {}
%\DeclareFontShapeChangeRule {sl}{sw}  {sw}    {}
\DeclareFontShapeChangeRule {sl}{sc}  {scsl}  {scit}
\DeclareFontShapeChangeRule {sl}{ulc} {sl}    {}
\DeclareFontShapeChangeRule {sl}{up} {n}      {}
%    \end{macrocode}
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {sc}{n}   {n}     {}
\DeclareFontShapeChangeRule {sc}{it}  {scit}  {scsl}
\DeclareFontShapeChangeRule {sc}{sl}  {scsl}  {scit}
\DeclareFontShapeChangeRule {sc}{sw}  {scsw}  {sw}
%\DeclareFontShapeChangeRule {sc}{sc}  {sc}    {}
\DeclareFontShapeChangeRule {sc}{ulc} {n}     {}
%    \end{macrocode}
%
%    The next rule might be a bit surprising and rightly so. Correct
%    would be that \texttt{sc} is not affected by \texttt{up}, i.e.,
%    remains \texttt{sc} as showed in the commented out rule. However,
%    for nearly three decades commands such as \upshape{sc} or
%    \cs{textup} changed small caps back to the ``normal'' shape. So
%    for backward compatibility we keep hat behavior.
%
%    As a result you are currently typesetting in \texttt{scit} or
%    \texttt{scsl} using \cs{upshape} twice will return you to the
%    normal shape too, the first will change to \texttt{sc} and the
%    second (because of the rule below) change that to
%    \texttt{n}. This is the way \texttt{fontspec} implemented its
%    version on this interface, so this rule means we are also
%    compatible with the way \texttt{fontspec} behaved. Still it
%    remains an odditywhic I would rather liked to have avoided.
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {sc}{up} {sc}     {}
\DeclareFontShapeChangeRule {sc}{up} {n}     {}
%    \end{macrocode}
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {scit}{n}   {n}    {}
\DeclareFontShapeChangeRule {scit}{it}  {scit}  {}
\DeclareFontShapeChangeRule {scit}{sl}  {scsl}  {scit}
\DeclareFontShapeChangeRule {scit}{sw}  {scsw}  {sc}    % or scit?
\DeclareFontShapeChangeRule {scit}{sc}  {scit}  {}
\DeclareFontShapeChangeRule {scit}{ulc} {it}    {}
\DeclareFontShapeChangeRule {scit}{up} {sc}     {}
%    \end{macrocode}
%    The previous rule assumes that if \texttt{scit} exists then
%    \texttt{it} exists as well. If not, the mechanism will save
%    \texttt{ulc} in \cs{f@series} which most certainly doesn't
%    exist. So when a font is later selected that would result in a
%    substitution (so no harm done really). Alternatively, we could in
%    this case use \texttt{n} as aternative, which may be a bit
%    faster, but such a  setup would be so weird in the first place
%    that this isn't worth the effort.
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {scsl}{n}   {n}     {}
\DeclareFontShapeChangeRule {scsl}{it}  {scit}  {scsl}
\DeclareFontShapeChangeRule {scsl}{sl}  {scsl}  {}
\DeclareFontShapeChangeRule {scsl}{sw}  {scsw}  {sc}    % or scsl?
\DeclareFontShapeChangeRule {scsl}{sc}  {scsl}  {}
\DeclareFontShapeChangeRule {scsl}{ulc} {sl}    {}
\DeclareFontShapeChangeRule {scsl}{up}   {sc}   {}
%    \end{macrocode}
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {scsw}{n}   {n}     {}
\DeclareFontShapeChangeRule {scsw}{it}  {scit}  {scsw}
\DeclareFontShapeChangeRule {scsw}{sl}  {scsl}  {}
\DeclareFontShapeChangeRule {scsw}{sw}  {scsw}  {}
\DeclareFontShapeChangeRule {scsw}{sc}  {scsw}  {}
\DeclareFontShapeChangeRule {scsw}{ulc} {sw}    {}
\DeclareFontShapeChangeRule {scsw}{up} {sc}     {}
%    \end{macrocode}
%
%    \begin{macrocode}
%\DeclareFontShapeChangeRule {sw}{n}   {n}     {}
%\DeclareFontShapeChangeRule {sw}{it}  {it}    {}
%\DeclareFontShapeChangeRule {sw}{sl}  {sl}    {}
%\DeclareFontShapeChangeRule {sw}{sw}  {sw}    {}
\DeclareFontShapeChangeRule {sw}{sc}  {scsw}  {}
\DeclareFontShapeChangeRule {sw}{ulc} {sw}    {}
\DeclareFontShapeChangeRule {sw}{up} {n}      {}
%    \end{macrocode}
%
%
% \subsection{Changing to a new shape}
%
%  \begin{macro}{\fontshape}
%    Again the \cs{fontshape} now has to do a lookup to get to its new
%    value in \cs{f@shape}. The method is exactly the same as in
%    \cs{fontseries}.
%    \begin{macrocode}
\DeclareRobustCommand\fontshape[1]{\merge@font@shape{#1}}
%    \end{macrocode}
%  \end{macro}
%
%
%  \begin{macro}{\fontshapeforce}
%    The unconditional version:
%    \begin{macrocode}
\DeclareRobustCommand\fontshapeforce[1]{\edef\f@shape{#1}}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\merge@font@shape}
%    Look up the database entry (if existing) and act accordingly.
%    \begin{macrocode}
\def\merge@font@shape#1{%
  \expandafter\expandafter\expandafter
  \merge@font@shape@
    \csname shape@\f@shape @#1\endcsname
    {#1}%
    \@nil
}
%    \end{macrocode}
%  \end{macro}
%

%  \begin{macro}{\merge@font@shape@}
%    Same game now, except that we look at shapes not series values
%    and we can set the shape without the complication of dropping
%    ``m''s from the name as we had to for the series.
%    \begin{macrocode}
\def\merge@font@shape@#1#2#3\@nil{%
  \def\reserved@a{#3}%
  \ifx\reserved@a\@empty
    \edef\f@shape{#2}%
  \else
    \maybe@load@fontshape
    \edef\reserved@a{\f@encoding /\f@family /\f@series/#1}%
     \ifcsname \reserved@a\endcsname
       \edef\f@shape{#1}%
    \else
       \ifcsname \f@encoding /\f@family /\f@series/#2\endcsname
         \edef\f@shape{#2}%
         \@font@shape@subst@warning
       \else
         \edef\f@shape{#3}%
         \@font@shape@subst@warning
       \fi
    \fi
  \fi
}
%    \end{macrocode}
%  \end{macro}
%
%
%
%  \begin{macro}{\normalshape}
%
%    \cs{normalshape} resets both sub-axes if the default rules are used.
%    \begin{macrocode}
\protected\def\normalshape
    {\not@math@alphabet\normalshape\relax
      \fontshape\shapedefault\selectfont}%
%    \end{macrocode}
%  \end{macro}
%
%
%
%
% \section{Make sure we win \ldots}
%
%    This code implements one aspect of what the package \textsf{fontaxes}
%    provide. So its redefinitions for the various shape commands,
%    such as \cs{itshape} should no longer happen. We therefore force
%    the standard definitions at \cs{AtBeginDocument} (later when this
%    is defined. Once
%    \texttt{fontaxes} is no longer doing such redefinitions that could
%    be taken out again.
%
%    We use a separate macro so that we can easily disable this (in
%    case of rollback).
%
%  \begin{macro}{\reinstall@nfss@defs}
%
%    I use \cs{protected} here not \cs{DeclareRobustCommand} to avoid
%    extra status lines.
%    \begin{macrocode}
\def\reinstall@nfss@defs{%
  \protected\def\upshape
          {\not@math@alphabet\upshape\relax
           \fontshape\updefault\selectfont}%
  \protected\def\slshape
          {\not@math@alphabet\slshape\relax
           \fontshape\sldefault\selectfont}%
  \protected\def\scshape
          {\not@math@alphabet\scshape\relax
           \fontshape\scdefault\selectfont}%
  \protected\def\itshape
          {\not@math@alphabet\itshape\mathit
           \fontshape\itdefault\selectfont}%
  \protected\def\ulcshape
          {\not@math@alphabet\ulcshape\relax
           \fontshape{ulc}\selectfont}%
  \protected\def\swshape
          {\not@math@alphabet\swshape\relax
           \fontshape\swdefault\selectfont}%
  \protected\def\sscshape
          {\not@math@alphabet\sscshape\relax
           \fontshape\sscdefault\selectfont}%
}
%    \end{macrocode}
%  \end{macro}
%
%
% Supporting rollback \ldots
%    \begin{macrocode}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%<latexrelease>\IncludeInRelease{0000/00/00}%
%<latexrelease>   {\DeclareFontSeriesChangeRule}{Series change rules}%
%<latexrelease>
%<latexrelease>\DeclareRobustCommand\fontseries[1]{\edef\f@series{#1}}
%<latexrelease>\DeclareRobustCommand\fontshape [1]{\edef\f@shape{#1}}
%<latexrelease>\let\fontseriesforce\@undefined
%<latexrelease>\let\fontshapeforce\@undefined
%<latexrelease>
%<latexrelease>\let\DeclareFontSeriesChangeRule\@undefined
%<latexrelease>\let\merge@font@series\@undefined
%<latexrelease>\let\merge@font@series@\@undefined
%<latexrelease>\let\@font@shape@subst@warning\@undefined
%<latexrelease>\let\maybe@load@fontshape\@undefined
%<latexrelease>\let\set@target@series\@undefined
%<latexrelease>\let\series@maybe@drop@one@m\@undefined
%<latexrelease>\let\series@drop@one@m\@undefined
%<latexrelease>\let\DeclareFontShapeChangeRule\@undefined
%<latexrelease>\let\merge@font@shape\@undefined
%<latexrelease>\let\merge@font@shape@\@undefined
%<latexrelease>\let\normalshape\@undefined
%<latexrelease>\let\ulcshape\@undefined
%<latexrelease>\let\ulcdefault\@undefined
%<latexrelease>\let\swshape\@undefined
%<latexrelease>\let\swdefault\@undefined
%<latexrelease>\let\sscshape\@undefined
%<latexrelease>\let\sscdefault\@undefined
%<latexrelease>\let\normalshape\@undefined
%    \end{macrocode}
%    This is always called in \cs{document} so don't make it undefined.
%    \begin{macrocode}
%<latexrelease>
%<latexrelease>\let\reinstall@nfss@defs\relax
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
%    \end{macrocode}
%
%    This initializes the 2020/02/02 extensions to NFSS after any changes
%    in the preamble. 
% \changes{v1.0g}{2020/08/21}{Integration of new hook management interface}
%    \begin{macrocode}
%</2ekernel>
%<*2ekernel|latexrelease>
%<latexrelease>\IncludeInRelease{2020/10/01}%
%<latexrelease>                 {\reinstall@nfss@defs}{NFSS series init}%
\g@addto@macro\@kernel@after@begindocument@before
              {\reinstall@nfss@defs\init@series@setup}
%</2ekernel|latexrelease>
%<latexrelease>\EndIncludeInRelease
%    \end{macrocode}
%
%    The initialization was introduced in 2020/02/02 but 
%    \begin{macrocode}
%<latexrelease>\IncludeInRelease{2020/02/02}%
%<latexrelease>                 {\reinstall@nfss@defs}{NFSS series init}%
%<latexrelease>\AtBeginDocument{\reinstall@nfss@defs\init@series@setup}
%<latexrelease>\EndIncludeInRelease
%    \end{macrocode}
%
%    \begin{macrocode}
%<latexrelease>\IncludeInRelease{0000/00/00}%
%<latexrelease>                 {\reinstall@nfss@defs}{NFSS series init}%
%<latexrelease>\EndIncludeInRelease
%<*2ekernel>
%</2ekernel>
%    \end{macrocode}
%
% \Finale
%