summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/source/latex/expl3/l3tlp.dtx
blob: 2d722a77624596f0e73957222bb1ddcb0844886e (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
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
% \iffalse
%% File: l3tlp.dtx Copyright (C) 1990-2008 LaTeX3 project
%%
%% It may be distributed and/or modified under the conditions of the
%% LaTeX Project Public License (LPPL), either version 1.3c of this
%% license or (at your option) any later version.  The latest version
%% of this license is in the file
%%
%%    http://www.latex-project.org/lppl.txt
%%
%% This file is part of the ``expl3 bundle'' (The Work in LPPL)
%% and all files in that bundle must be distributed together.
%%
%% The released version of this bundle is available from CTAN.
%%
%% -----------------------------------------------------------------------
%%
%% The development version of the bundle can be found at
%%
%%    http://www.latex-project.org/cgi-bin/cvsweb.cgi/
%%
%% for those people who are interested.
%%
%%%%%%%%%%%
%% NOTE: %%
%%%%%%%%%%%
%%
%%   Snapshots taken from the repository represent work in progress and may
%%   not work or may contain conflicting material!  We therefore ask
%%   people _not_ to put them into distributions, archives, etc. without
%%   prior consultation with the LaTeX Project Team.
%%
%% -----------------------------------------------------------------------
%
%<*driver|package>
\RequirePackage{l3names}
%</driver|package>
%\fi
\GetIdInfo$Id: l3tlp.dtx 767 2008-08-05 19:44:21Z morten $
          {L3 Experimental Token List Pointers}
%\iffalse
%<*driver>
%\fi
\ProvidesFile{\filename.\filenameext}
  [\filedate\space v\fileversion\space\filedescription]
%\iffalse
\documentclass{l3doc}
\begin{document}
\DocInput{\filename.\filenameext}
\end{document}
%</driver>
% \fi
%
%
% \title{The \textsf{l3tlp} package\thanks{This file
%         has version number \fileversion, last
%         revised \filedate.}\\
% Token List Pointers}
% \author{\Team}
% \date{\filedate}
% \maketitle
%
%
%
% \section {Token list pointers}
%
% \LaTeX3 stores token lists in so called `token list pointers'.
% Variables of this type get the suffix "tlp" and functions of this type
% have the prefix "tlp". To use a  token list pointer you simply call
% the corresponding variable.
%
% Often you find yourself with not a token list pointer but an
% arbitrary token list which has to undergo certain tests. We will
% prefix these functions with "tlist". While token list pointers are
% always single tokens, token lists are always surrounded by
% braces. Perhaps these token lists should have their own module but
% for now I decided to put them here because there is quite a bit of
% overlap with token list pointers.
%
% \subsection{Functions}
%
% \begin{function}{\tlp_new:N  |
%                  \tlp_new:c  |
%                  \tlp_new:Nn |
%                  \tlp_new:cn |
%                  \tlp_new:Nx }
% \begin{syntax}
%    "\tlp_new:Nn" <tlp> "{" <initial token list> "}"
% \end{syntax}
% Defines <tlp> to be a new variable (or constant) of type token list
% pointer. <initial token list> is the initial value of <tlp>. This
% makes it possible to assign values to a constant token list pointer.
%
% The form "\tlp_new:N" initializes the token list pointer with an empty value.
% \end{function}
%
% \begin{function}{%
%                  \tlp_use:N |
%                  \tlp_use:c
% }
% \begin{syntax}
%   "\tlp_use:N" <tlp>
% \end{syntax}
% Function that inserts the <tlp> into the processing stream. Instead of
% |\tlp_use:N| simply placing the <tlp> into the input stream is also
% supported.|\tlp_use:c| will complain is the <tlp> hasn't been declared
% previously!
% \end{function}
%
% \begin{function}{%
%                  \tlp_set:Nn |
%                  \tlp_set:Nc |
%                  \tlp_set:No |
%                  \tlp_set:Nd |
%                  \tlp_set:Nf |
%                  \tlp_set:Nx |
%                  \tlp_gset:Nn |
%                  \tlp_gset:Nc |
%                  \tlp_gset:No |
%                  \tlp_gset:Nd |
%                  \tlp_gset:Nx |
%                  \tlp_gset:cn |
%                  \tlp_gset:cx }
% \begin{syntax}
%   "\tlp_set:Nn" <tlp> "{" <token list> "}"
% \end{syntax}
% Defines <tlp> to hold the token list <token list>. Global
% variants of this command assign the value globally the other variants
% expand the <token list> up to a certain level before the assignment
% or interpret the <token list> as a character list and form a control
% sequence out of it.
% \end{function}
%
% \begin{function}{%
%                  \tlp_clear:N |
%                  \tlp_clear:c |
%                  \tlp_gclear:N |
%                  \tlp_gclear:c
% }
% \begin{syntax}
%   "\tlp_clear:N" <tlp>
% \end{syntax}
% The <tlp> is locally or globally cleared. The "c" variants will
% generate a control sequence name which is then interpreted as
% <tlp> before clearing.
% \end{function}
%
% \begin{function}{%
%                  \tlp_clear_new:N |
%                  \tlp_clear_new:c |
%                  \tlp_gclear_new:N |
%                  \tlp_gclear_new:c |
% }
% \begin{syntax}
%   "\tlp_clear_new:N" <tlp>
% \end{syntax}
% These functions check if <tlp> exists. If it does it will be cleared;
% if it doesn't it will be allocated.
% \end{function}
%
% \begin{function}{%
%                  \tlp_put_left:Nn |
%                  \tlp_put_left:No |
%                  \tlp_put_left:Nx |
%                  \tlp_gput_left:Nn |
%                  \tlp_gput_left:No |
%                  \tlp_gput_left:Nx |
%                  \tlp_put_right:Nn |
%                  \tlp_put_right:No |
%                  \tlp_put_right:Nx |
%                  \tlp_put_right:cc |
%                  \tlp_gput_right:Nn |
%                  \tlp_gput_right:No|
%                  \tlp_gput_right:Nx|
%                  \tlp_gput_right:cn|
%                  \tlp_gput_right:co|
% }
% \begin{syntax}
%   "\tlp_put_left:Nn" <tlp> "{" <token list> "}"
% \end{syntax}
% These functions will append <token list> to the left or right of
% <tlp>. Assignment is done either locally or globally and <token
% list> might be subject to expansion before assignment.
% \end{function}
%
% A word of warning is appropriate here: Token list pointers are
% implemented as macros and as such currently inherit some of the
% peculiarities of how \TeX\ handles "#"s in the argument of
% macros. In particular, the following actions are legal
% \begin{verbatim}
% \tlp_set:Nn \l_tmpa_tlp{##1}
% \tlp_put_right:Nn \l_tmpa_tlp{##2}
% \tlp_set:No \l_tmpb_tlp{\l_tmpa_tlp ##3}
% \end{verbatim}
% |x| type expansions where macros being expanded contain |#|s do not
% work and will not work until there is an |\expanded| primitive in
% the engine. If you want them to work you must double |#|s another
% level.
%
%
% \begin{function}{%
%                  \tlp_set_eq:NN |
%                  \tlp_set_eq:Nc |
%                  \tlp_set_eq:cN |
%                  \tlp_set_eq:cc |
%                  \tlp_gset_eq:NN |
%                  \tlp_gset_eq:Nc |
%                  \tlp_gset_eq:cN |
%                  \tlp_gset_eq:cc |
% }
% \begin{syntax}
%    "\tlp_set_eq:NN" <tlp1> <tlp2>
% \end{syntax}
% Fast form for
% \begin{syntax}
%    "\tlp_set:No" <tlp1> "{" <tlp2> "}"
% \end{syntax}
% when <tlp2> is known to be a variable of type token list pointer.
% \end{function}
%
% \begin{function}{\tlp_to_str:N |
%                  \tlp_to_str:c
% }
% \begin{syntax}
%   "\tlp_to_str:N" <tlp>
% \end{syntax}
% This function returns the token list kept in <tlp> as a string list
% with all characters catcoded to `other'.
% \end{function}
%
% \subsection{Predicates and conditionals}
%
% \begin{function}{\tlp_if_empty_p:N|
%                  \tlp_if_empty_p:c
%                  }
% \begin{syntax}
%   "\tlp_if_empty_p:N" <tlp>
% \end{syntax}
% This predicate returns `true' if <tlp> is `empty' i.e., doesn't
% contain any tokens.
% \end{function}
%
% \begin{function}{\tlp_if_empty:NTF|
%                  \tlp_if_empty:NT|
%                  \tlp_if_empty:NF|
%                  \tlp_if_empty:cTF |
%                  \tlp_if_empty:cT  |
%                  \tlp_if_empty:cF
% }
% \begin{syntax}
%   "\tlp_if_empty:NTF" <tlp> "{"<true code>"}""{"<false code>"}"
% \end{syntax}
% Execute <true code> if <tlp> is empty and <false code> if it
% contains any tokens.
% \end{function}
%
% \begin{function}{\tlp_if_eq_p:NN |
%                  \tlp_if_eq_p:cN |
%                  \tlp_if_eq_p:Nc |
%                  \tlp_if_eq_p:cc |
%                  }
% \begin{syntax}
%   "\tlp_if_eq_p:NN" <tlp1> <tlp2> 
% \end{syntax}
% Predicate function which returns `true' if the two token list
% pointers are identical and `false' otherwise.
% \end{function}
%
% \begin{function}{
%                  \tlp_if_eq:NNTF |
%                  \tlp_if_eq:NNT |
%                  \tlp_if_eq:NNF |
%                  \tlp_if_eq:cNTF |
%                  \tlp_if_eq:cNT |
%                  \tlp_if_eq:cNF |
%                  \tlp_if_eq:NcTF |
%                  \tlp_if_eq:NcT |
%                  \tlp_if_eq:NcF |
%                  \tlp_if_eq:ccTF |
%                  \tlp_if_eq:ccT |
%                  \tlp_if_eq:ccF |
%  }
%  \begin{syntax}
%   "\tlp_if_eq:NNTF" <tlp1> <tlp2> "{"<true code>"}""{"<false code>"}"
% \end{syntax}
% Execute <true code> if <tlp1> holds the same token list as <tlp2>
% and <false code> otherwise.
% \end{function}
%
%
% \subsection{Token lists}
%
% \begin{function}{\tlist_if_eq:nnTF |
%                  \tlist_if_eq:nnT |
%                  \tlist_if_eq:nnF |
%                  \tlist_if_eq:noTF |
%                  \tlist_if_eq:noT |
%                  \tlist_if_eq:noF |
%                }
% \begin{syntax}
%   "\tlist_if_eq:nnTF" "{"<tlist1>"}" "{"<tlist2>"}" "{"<true
%     code>"}" "{"<false code>"}"
% \end{syntax}
% Execute <true code> if the two token lists <tlist1> and <tlist2> are
% identical.
% \end{function}
%
%
% \begin{function}{\tlist_if_empty_p:n |
%                  \tlist_if_empty_p:o |
%                  \tlist_if_empty:nTF |
%                  \tlist_if_empty:nT |
%                  \tlist_if_empty:nF |
%                  \tlist_if_empty:oTF |
%                  \tlist_if_empty:oT |
%                  \tlist_if_empty:oF |
%                  }
% \begin{syntax}
%   "\tlist_if_empty:nTF" "{"<tlist>"}" "{"<true code>"}" "{"<false code>"}"
% \end{syntax}
% Execute <true code> if <tlist> doesn't contain any tokens and <false
% code> otherwise.
% \end{function}
%
% \begin{function}{\tlist_if_blank_p:n |
%                  \tlist_if_blank:nTF |
%                  \tlist_if_blank:nT |
%                  \tlist_if_blank:nF |
%                  \tlist_if_blank_p:o |
%                  \tlist_if_blank:oTF |
%                  \tlist_if_blank:oT |
%                  \tlist_if_blank:oF |
%                  }
% \begin{syntax}
%   "\tlist_if_blank:nTF" "{"<tlist>"}" "{"<true code>"}" "{"<false code>"}"
% \end{syntax}
% Execute <true code> if <tlist> is blank meaning that it is either
% empty or contains only blank spaces.
% \end{function}
%
% \begin{function}{\tlist_to_lowercase:n |
%                  \tlist_to_uppercase:n 
%                  }
% \begin{syntax}
%   "\tlist_to_lowercase:n" "{"<tlist>"}"
% \end{syntax}
% "\tlist_to_lowercase:n" converts all tokens in <tlist> to their
% lower case representation. Similar for "\tlist_to_uppercase:n".
% \begin{texnote}
%   These are the \TeX\ primitives \tn{lowercase} and \tn{uppercase}
%   renamed.
% \end{texnote}
% \end{function}
%
% \begin{function}{\tlist_to_str:n 
%                  }
% \begin{syntax}
%   "\tlist_to_str:n" "{"<tlist>"}"
% \end{syntax}
% This function turns its argument into a string where all characters
% have catcode `other'.
% \begin{texnote}
%   This is the \eTeX\ primitive \tn{detokenize}.
% \end{texnote}
% \end{function}
%
%  \begin{function}{%
%                   \tlist_map_function:nN |
%                   \tlp_map_function:NN |
%                   \tlp_map_function:cN |
%  }
%  \begin{syntax}
%     "\tlist_map_function:nN" "{"<tlist>"}" <function> \\
%     "\tlp_map_function:NN" <tlp> <function>
%  \end{syntax}
%  Runs through all elements in a |tlist| from left to right and places
%  <function> in front of each element. As this function will also pick
%  up elements in brace groups, the element is returned with braces and
%  hence <function> should be a function with a |:n| suffix even though
%  it may very well only deal with a single token. This function uses a
%  purely expandable loop function and will stay so as long as
%  <function> is expandable too.
%  \end{function}
%
%  \begin{function}{%
%                   \tlist_map_inline:nn |
%                   \tlp_map_inline:Nn |
%                   \tlp_map_inline:cn |
%  }
%  \begin{syntax}
%     "\tlist_map_inline:nn" "{"<tlist>"}" "{"<inline~function>"}" \\
%     "\tlp_map_inline:Nn" <tlp> "{"<inline~function>"}"
%  \end{syntax}
%  Allows a syntax like "\tlist_map_inline:nn" "{"<tlist>"}"
%  "{\token_to_string:N ##1}". This renders it non-expandable though.
%  Remember to double the "#"s for each level.
%  \end{function}
%
%
%  \begin{function}{%
%                   \tlist_map_variable:nNn |
%                   \tlp_map_variable:NNn |
%                   \tlp_map_variable:cNn |
%  }
%  \begin{syntax}
%     "\tlist_map_variable:nNn" "{"<tlist>"}" <temp> "{"<action>"}" \\
%     "\tlp_map_variable:NNn" <tlp> <temp> "{"<action>"}"
%  \end{syntax}
%  Assigns <temp> to each element on <tlist> and executes <action>.
%  As there is an assignment in this process it is not expandable.
%  \begin{texnote}
%  This is the \LaTeX2{} function \tn{@tfor} but with a more sane syntax.
%  Also it works by tail recursion and so is faster as lists grow longer.
%  \end{texnote}
%  \end{function}
%
%  \begin{function}{%
%                   \tlist_map_break:w |
%                   \tlp_map_break:w |
%  }
%  \begin{syntax}
%     "\tlist_map_break:w"
%  \end{syntax}
%  For breaking out of a loop. You should take note of the ":w" as
%  its usage must be precise!
%  \end{function}
%
%
%  \begin{function}{%
%                   \tlist_reverse:n |
%  }
%  \begin{syntax}
%     "\tlist_reverse:n" "{"<token$\sb1$><token$\sb2$>...<token$\sb n$>"}"
%  \end{syntax}
%  Reverse the token list to result in
%  <token$\sb n$>\dots<token$\sb2$><token$\sb1$>. Note that spaces in this
%  token list are gobbled in the process.
%  \end{function}
%
%  \begin{function}{%
%                   \tlist_elt_count:n |
%                   \tlist_elt_count:o |
%                   \tlp_elt_count:N |
%  }
%  \begin{syntax}
%     "\tlist_elt_count:n" "{"<token list>"}" \\
%     "\tlp_elt_count:N"   <tlp>
%  \end{syntax}
%  Returns the number of elements in the token list. Brace groups
%  encountered count as one element. Note that spaces in this
%  token list are gobbled in the process.
%  \end{function}
%
%
% \subsubsection{Internal functions}
%
%
%  \begin{function}{%
%                   \tlist_map_function_aux:Nn |
%                   \tlist_map_inline_aux:Nn |
%                   \tlist_map_variable_aux:Nnn |
%  }
%  \begin{syntax}\end{syntax}
%  Internal helper functions for the <tlist> loops.
%  \end{function}
%
%
%
% \begin{function}{\tlist_if_blank_p_aux:w 
%                  }
% \end{function}
%
%
%
% \subsection{Variables and constants}
%
% \begin{variable}{\C_job_name_tlp}
% Constant that gets the `job name' assigned when \TeX{} starts.
% \begin{texnote}
% This is the new name for the primitive \tn{jobname}. It is a constant
% that will be set by \TeX{} and can not be overwritten by the package.
% Therefore the "C"
% \end{texnote}
% \end{variable}
%
% \begin{variable}{\c_empty_tlp}
% Constant that is always empty.
% \begin{texnote}
% This was named \tn{@empty} in \LaTeX2 and \tn{empty} in plain \TeX{}.
% \end{texnote}
% \end{variable}
%
% \begin{variable}{\c_relax_tlp}
% Constant holding the token that is assigned to a newly created control
% sequence by \TeX.
% \end{variable}
%
% \begin{variable}{%
%                  \l_tmpa_tlp |
%                  \l_tmpb_tlp |
%                  \g_tmpa_tlp |
%                  \g_tmpb_tlp
% }
% Scratch register for immediate use. They are not used by conditionals
% or predicate functions.
% \end{variable}
%
%
% \subsubsection{Internal functions}
%
% \begin{variable}{%
%                  \l_replace_tlp |
% }
% Internal register used in the replace functions.
% \end{variable}
%
% \begin{variable}{%
%                  \l_testa_tlp |
%                  \l_testb_tlp |
%                  \g_testa_tlp |
%                  \g_testb_tlp |
% }
% Registers used for conditional processing if the engine doesn't
% support arbitrary string comparison.
% \end{variable}
%
%
% \begin{function}{\tlp_to_str_aux:w}
% Function used to implement "\tlp_to_str:N".
% \end{function}
%
%
% \subsection{Search and replace}
%
%
% \begin{function}{
%                  \tlp_if_in:NnTF |
%                  \tlp_if_in:cnTF |
%                  \tlp_if_in:NnT |
%                  \tlp_if_in:cnT |
%                  \tlp_if_in:NnF |
%                  \tlp_if_in:cnF |
%                  \tlist_if_in:nnTF |
%                  \tlist_if_in:onTF |
%                  }
% \begin{syntax}
%   "\tlp_if_in:NnTF" <tlp> "{" <item> "}{" <true code> "}{"
%     <false code> "}"
% \end{syntax}
% Function that tests if <item> is in <tlp>. Depending on the result
% either <true code> or <false code> is executed. Note that <item>
% cannot contain brace groups.
% \end{function}
%
% \begin{function}{
%                  \tlp_replace_in:Nnn |
%                  \tlp_replace_in:cnn |
%                  \tlp_greplace_in:Nnn |
%                  \tlp_greplace_in:cnn |
%                  }
% \begin{syntax}
%   "\tlp_replace_in:Nnn" <tlp> "{" <item1> "}{" <item2> "}"
% \end{syntax}
% Replaces the leftmost occurrence of <item1> in <tlp> with
% <item2> if present, otherwise the <tlp> is left untouched.
% \end{function}
%
% \begin{function}{
%                  \tlp_replace_all_in:Nnn |
%                  \tlp_replace_all_in:cnn |
%                  \tlp_greplace_all_in:Nnn |
%                  \tlp_greplace_all_in:cnn |
%                  }
% \begin{syntax}
%   "\tlp_replace_all_in:Nnn" <tlp> "{" <item1> "}{" <item2> "}"
% \end{syntax}
% Replaces \emph{all} occurrences of <item1> in <tlp> with
% <item2>.
% \end{function}
%
%
% \begin{function}{
%                  \tlp_remove_in:Nn |
%                  \tlp_remove_in:cn |
%                  \tlp_gremove_in:Nn |
%                  \tlp_gremove_in:cn |
%                  }
% \begin{syntax}
%   "\tlp_remove_in:Nn" <tlp> "{" <item> "}"
% \end{syntax}
% Removes the leftmost occurrence of <item> from <tlp> if present.
% \end{function}
%
%
% \begin{function}{
%                  \tlp_remove_all_in:Nn |
%                  \tlp_remove_all_in:cn |
%                  \tlp_gremove_all_in:Nn |
%                  \tlp_gremove_all_in:cn |
%                  }
% \begin{syntax}
%   "\tlp_remove_all_in:Nn" <tlp> "{" <item> "}"
% \end{syntax}
% Removes \emph{all} occurrences of <item> from <tlp>.
% \end{function}
%
%
% \subsection{Heads or tails?}
%
% Here are some functions for grabbing either the head or tail of a
% list and perform some tests on it.
% 
% \begin{function}{%
%                  \tlist_head:n |
%                  \tlist_tail:n |
%                  \tlist_head_iii:n |
%                  \tlist_head_iii:f |
%                  \tlist_head:w |
%                  \tlist_tail:w |
%                  \tlist_head_iii:w
% }
% \begin{syntax}
%   "\tlist_head:n"  "{" <token1><token2>...<token-n> "}" \\
%   "\tlist_tail:n"  "{" <token1><token2>...<token-n> "}"
% \end{syntax}
% These functions return either the head or the tail of a list, thus in
% the above example "\tlist_head:n" would return <token1> and "\tlist_tail:n"
% would return <token2>\dots<token-n>. "\tlist_head_iii:n" returns the first
% three tokens. The ":w" versions require some care as they use a
% delimited argument internally.
% \begin{texnote}
% These are the Lisp functions "car" and "cdr" but with \LaTeX3 names.
% \end{texnote}
% \end{function}
%
%
%
%
% \begin{function}{%
%                  \tlist_if_head_eq_meaning_p:nN |
%                  \tlist_if_head_eq_meaning:nNTF |
%                  \tlist_if_head_eq_meaning:nNTF |
%                  \tlist_if_head_eq_meaning:nNTF |
% }
% \begin{syntax}
%   "\tlist_if_head_eq_meaning:nNTF" "{" <token list> "}" <token>
%   "{"<true>"}""{"<false>"}"
% \end{syntax}
% Returns <true> if the first token in <token list> is equal to
% <token> and <false> otherwise. The |meaning| version compares the
% two tokens with |\if_meaning:NN|.
% \end{function}
%
% \begin{function}{%
%                  \tlist_if_head_eq_charcode_p:nN |
%                  \tlist_if_head_eq_charcode:nNTF |
%                  \tlist_if_head_eq_charcode:nNTF |
%                  \tlist_if_head_eq_charcode:nNTF |
% }
% \begin{syntax}
%   "\tlist_if_head_eq_charcode:nNTF" "{" <token list> "}" <token>
%   "{"<true>"}""{"<false>"}"
% \end{syntax}
% Returns <true> if the first token in <token list> is equal to
% <token> and <false> otherwise. The |meaning| version compares the
% two tokens with |\if_charcode:w| but it prevents expansion of
% them. If you want them to expand, you can use an |f| type expansion
% first (define |\tlist_if_head_eq_charcode:fNTF| or similar).
% \end{function}
%
% \begin{function}{%
%                  \tlist_if_head_eq_catcode_p:nN |
%                  \tlist_if_head_eq_catcode:nNTF |
%                  \tlist_if_head_eq_catcode:nNTF |
%                  \tlist_if_head_eq_catcode:nNTF |
% }
% \begin{syntax}
%   "\tlist_if_head_eq_catcode:nNTF" "{" <token list> "}" <token>
%   "{"<true>"}""{"<false>"}"
% \end{syntax}
% Returns <true> if the first token in <token list> is equal to
% <token> and <false> otherwise. This version uses |\if_catcode:w| for
% the test but is otherwise identical to the |charcode| version.
% \end{function}
%
%
% \StopEventually{}
%
%    \subsection{The Implementation}
%
%    We start by ensuring that the required packages are loaded.
%    \begin{macrocode}
%<package>\ProvidesExplPackage
%<package>  {\filename}{\filedate}{\fileversion}{\filedescription}
%<package&!check>\RequirePackage{l3basics}
%<package&check>\RequirePackage{l3chk}
%    \end{macrocode}
%    \begin{macrocode}
%<*initex|package>
%    \end{macrocode}
%
% A token list pointer is a control sequence that holds tokens.  The
% interface is similar to that for token registers, but beware that
% the behavior vis \'a vis |\def:Npx| etc. \ldots{} is different.  (You
% see this comes from Denys' implementation.)
%
%
%
% \begin{macro}{\tlp_new:N}
% \begin{macro}{\tlp_new:c}
% \begin{macro}{\tlp_new:Nn}
% \begin{macro}{\tlp_new:cn}
% \begin{macro}{\tlp_new:Nx}
%    We provide one allocation function (which checks that the name is
%    not used) and two clear functions that locally or globally clear
%    the token list. The allocation function has two arguments to
%    specify an initial value. This is the only way to give values to
%    constants.
%    \begin{macrocode}
\def_long_new:Npn \tlp_new:Nn #1#2{
  \chk_new_cs:N #1
%    \end{macrocode}
%  If checking we don't allow constants to be defined.
%    \begin{macrocode}
%<*check>
  \chk_var_or_const:N #1
%</check>
%    \end{macrocode}
%    Otherwise any variable type is allowed.
%    \begin{macrocode}
  \gdef:Npn #1{#2}
}
\def_new:Npn \tlp_new:cn {\exp_args:Nc \tlp_new:Nn }
\def_long_new:Npn \tlp_new:Nx #1#2{
  \chk_new_cs:N #1
%<check> \chk_var_or_const:N #1
  \gdef:Npx #1{#2}
}
\def_new:Npn \tlp_new:N #1{\tlp_new:Nn #1{}}
\def_new:Npn \tlp_new:c #1{\tlp_new:cn {#1}{}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\tlp_use:N}
% \begin{macro}{\tlp_use:c}
% Perhaps this should just be enabled when checking?
%    \begin{macrocode}
\def_new:Npn \tlp_use:N #1 {
  \if_meaning:NN #1 \scan_stop:
%    \end{macrocode}
%  If \m{tlp} equals |\scan_stop:| it is probably stemming from a
%  |\cs:w ... \cd_end:| that was created by mistake somewhere.
%    \begin{macrocode}
     \err_latex_bug:x {Token~list~pointer~ `\token_to_string:N #1'~
                       has~ an~ erroneous~ structure!}
  \else:
    \exp_after:NN #1
  \fi:
}
\def_new:Npn \tlp_use:c {\exp_args:Nc \tlp_use:N}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\tlp_set:Nn}
% \begin{macro}{\tlp_set:No}
% \begin{macro}{\tlp_set:Nd}
% \begin{macro}{\tlp_set:Nf}
% \begin{macro}{\tlp_set:Nx}
% \begin{macro}{\tlp_set:cn}
% \begin{macro}{\tlp_set:co}
% \begin{macro}{\tlp_set:cx}
% \begin{macro}{\tlp_gset:Nn}
% \begin{macro}{\tlp_gset:No}
% \begin{macro}{\tlp_gset:Nd}
% \begin{macro}{\tlp_gset:Nx}
% \begin{macro}{\tlp_gset:cn}
% \begin{macro}{\tlp_gset:cx}
%    To set token lists to a specific value to type of functions are
%    available: |\tlp_set_eq:NN| takes two token-lists as its
%    arguments assign the first the contents of the second;
%    |\tlp_set:Nn| has as its second argument a `real' list of tokens.
%    One can view |\tlp_set_eq:NN| as a special form of |\tlp_set:No|.
%    Both functions have global counterparts.
%
%    During development we check if the token list that is being
%    assigned to exists. If not, a warning will be issued.
%    \begin{macrocode}
%<*check>
\def_long_new:Npn \tlp_set:Nn #1#2{
  \chk_exist_cs:N #1  \def:Npn #1{#2}
%    \end{macrocode}
%    We use |\chk_local_or_pref_global:N| after the assignment to
%    allow constructs with |\pref_global_chk:|. But one should note
%    that this is less efficient then using the real global variant
%    since they are built-in.
%    \begin{macrocode}
  \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_set:Nx #1#2{
  \chk_exist_cs:N #1  \def:Npx #1{#2}  \chk_local:N #1
}
%    \end{macrocode}
%  The the global versions.
%    \begin{macrocode}
\def_long_new:Npn \tlp_gset:Nn #1#2{
  \chk_exist_cs:N #1  \gdef:Npn #1{#2}  \chk_global:N #1
}
\def_long_new:Npn \tlp_gset:Nx #1#2{
  \chk_exist_cs:N #1  \gdef:Npx #1{#2}  \chk_global:N #1
}
%</check>
%    \end{macrocode}
%    For some functions like |\tlp_set:Nn| we need to define the
%    `non-check' version with  arguments since we want to allow
%    constructions like |\tlp_set:Nn\l_tmpa_tlp\foo| and so we can't
%    use the primitive \TeX{} command.
%    \begin{macrocode}
%<*!check>
\def_long_new:Npn\tlp_set:Nn#1#2{\def:Npn#1{#2}}
\def_long_new:Npn\tlp_set:Nx#1#2{\def:Npx#1{#2}}
\def_long_new:Npn\tlp_gset:Nn#1#2{\gdef:Npn#1{#2}}
\def_long_new:Npn\tlp_gset:Nx#1#2{\gdef:Npx#1{#2}}
%</!check>
%    \end{macrocode}
%  The remaining functions can just be defined with help from the
%  expansion module.
%    \begin{macrocode}
\def_new:Npn \tlp_set:No {\exp_args:NNo \tlp_set:Nn}
\def_new:Npn \tlp_set:Nd {\exp_args:NNd \tlp_set:Nn}
\def_new:Npn \tlp_set:Nf {\exp_args:NNf \tlp_set:Nn}
\def_new:Npn \tlp_set:cn {\exp_args:Nc  \tlp_set:Nn}
\def_new:Npn \tlp_set:co {\exp_args:Nco \tlp_set:Nn}
\def_new:Npn \tlp_set:cx {\exp_args:Nc  \tlp_set:Nx}
\def_new:Npn \tlp_gset:No {\exp_args:NNo \tlp_gset:Nn}
\def_new:Npn \tlp_gset:Nd {\exp_args:NNd \tlp_gset:Nn}
\def_new:Npn \tlp_gset:cn {\exp_args:Nc \tlp_gset:Nn}
\def_new:Npn \tlp_gset:cx {\exp_args:Nc \tlp_gset:Nx}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_set_eq:NN}
% \begin{macro}{\tlp_set_eq:Nc}
% \begin{macro}{\tlp_set_eq:cN}
% \begin{macro}{\tlp_set_eq:cc}
% \begin{macro}{\tlp_gset_eq:NN}
% \begin{macro}{\tlp_gset_eq:Nc}
% \begin{macro}{\tlp_gset_eq:cN}
% \begin{macro}{\tlp_gset_eq:cc}
%  For setting token list pointers equal to each other. First checking:
%    \begin{macrocode}
%<*check>
\def_new:Npn \tlp_set_eq:NN #1#2{
  \chk_exist_cs:N #1  \let:NN #1#2
  \chk_local_or_pref_global:N #1  \chk_var_or_const:N #2
}
\def_new:Npn \tlp_gset_eq:NN #1#2{
  \chk_exist_cs:N #1  \glet:NN #1#2
  \chk_global:N #1  \chk_var_or_const:N #2
}
%</check>
%    \end{macrocode}
%  Non-checking versions are easy.
%    \begin{macrocode}
%<*!check>
\let_new:NN \tlp_set_eq:NN \let:NN
\let_new:NN \tlp_gset_eq:NN \glet:NN
%</!check>
%    \end{macrocode}
%  The rest again with the expansion module.
%    \begin{macrocode}
\def_new:Npn \tlp_set_eq:Nc {\exp_args:NNc \tlp_set_eq:NN}
\def_new:Npn \tlp_set_eq:cN {\exp_args:Nc  \tlp_set_eq:NN}
\def_new:Npn \tlp_set_eq:cc {\exp_args:Ncc \tlp_set_eq:NN}
\def_new:Npn \tlp_gset_eq:Nc {\exp_args:NNc \tlp_gset_eq:NN}
\def_new:Npn \tlp_gset_eq:cN {\exp_args:Nc  \tlp_gset_eq:NN}
\def_new:Npn \tlp_gset_eq:cc {\exp_args:Ncc \tlp_gset_eq:NN}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%
% \begin{macro}{\tlp_clear:N}
% \begin{macro}{\tlp_clear:c}
% \begin{macro}{\tlp_gclear:N}
% \begin{macro}{\tlp_gclear:c}
%    Clearing a token list pointer.
%    \begin{macrocode}
\def_new:Npn \tlp_clear:N #1{\tlp_set_eq:NN #1\c_empty_tlp}
\def_new:Npn \tlp_clear:c {\exp_args:Nc \tlp_clear:N}
\def_new:Npn \tlp_gclear:N #1{\tlp_gset_eq:NN #1\c_empty_tlp}
\def_new:Npn \tlp_gclear:c {\exp_args:Nc \tlp_gclear:N}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_clear_new:N}
% \begin{macro}{\tlp_clear_new:c}
%    These macros check whether a token list exists. If it does it
%    is cleared, if it doesn't it is allocated.
%    \begin{macrocode}
%<*check>
\def_new:Npn \tlp_clear_new:N #1{
  \chk_var_or_const:N #1
  \if:w \cs_exist_p:N #1
    \tlp_clear:N #1
  \else:
    \tlp_new:Nn #1{}
  \fi:
}
%</check>
%<-check>\let_new:NN \tlp_clear_new:N \tlp_clear:N
\def_new:Npn \tlp_clear_new:c {\exp_args:Nc \tlp_clear_new:N}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_gclear_new:N}
% \begin{macro}{\tlp_gclear_new:c}
%    These are the global versions of the above.
%    \begin{macrocode}
%<*check>
\def_new:Npn \tlp_gclear_new:N #1{
  \chk_var_or_const:N #1
  \if:w \cs_exist_p:N #1
    \tlp_gclear:N #1
  \else:
    \tlp_new:Nn #1{}
  \fi:}
%</check>
%<-check>\let_new:NN \tlp_gclear_new:N \tlp_gclear:N
\def_new:Npn \tlp_gclear_new:c {\exp_args:Nc \tlp_gclear_new:N}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_put_left:Nn}
% \begin{macro}{\tlp_put_left:No}
% \begin{macro}{\tlp_put_left:Nx}
% \begin{macro}{\tlp_gput_left:Nn}
% \begin{macro}{\tlp_gput_left:No}
% \begin{macro}{\tlp_gput_left:Nx}
%   We can add tokens to the left (either globally or locally). It is
%   not quite as easy as we would like because we have to ensure the
%   assignments
% \begin{verbatim}
% \tlp_set:Nn \l_tmpa_tlp{##1abc##2def}
% \tlp_set:Nn \l_tmpb_tlp{##1abc}
% \tlp_put_right:Nn \l_tmpb_tlp {##2def}
% \end{verbatim}
%   cause |\l_tmpa_tlp| and |\l_tmpb_tlp| to be identical. The old
%   code did not succeed in doing this (it gave an error) and so we
%   use a different technique where the item(s) to be added are first
%   stored in a temporary pointer and then added using an |x| type
%   expansion combined with the appropriate level of
%   non-expansion. Putting the tokens directly into one assignment
%   does not work unless we want full expansion. Note (according to
%   the warning earlier) \TeX\ does not allow us to treat |#|s the
%   same in all cases. Tough.
%    \begin{macrocode}
\def_long_new:Npn \tlp_put_left:Nn #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_set:Nx #1{\exp_not:o{\l_exp_tlp}\exp_not:o{#1}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_put_left:No #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_set:Nx #1{\exp_not:d{\l_exp_tlp}\exp_not:o{#1}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_put_left:Nx #1#2{
  \tlp_set:Nx #1{#2\exp_not:o{#1}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_gput_left:Nn #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_gset:Nx #1{\exp_not:o{\l_exp_tlp}\exp_not:o{#1}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_gput_left:No #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_gset:Nx #1{\exp_not:d{\l_exp_tlp}\exp_not:o{#1}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_gput_left:Nx #1#2{
  \tlp_gset:Nx #1{#2\exp_not:o{#1}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_put_left:cn{\exp_args:Nc\tlp_put_left:Nn}
\def_long_new:Npn \tlp_put_left:co{\exp_args:Nc\tlp_put_left:No}
\def_long_new:Npn \tlp_put_left:cx{\exp_args:Nc\tlp_put_left:Nx}
\def_long_new:Npn \tlp_gput_left:cn{\exp_args:Nc\tlp_gput_left:Nn}
\def_long_new:Npn \tlp_gput_left:co{\exp_args:Nc\tlp_gput_left:No}
\def_long_new:Npn \tlp_gput_left:cx{\exp_args:Nc\tlp_gput_left:Nx}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_put_right:Nn}
% \begin{macro}{\tlp_put_right:No}
% \begin{macro}{\tlp_put_right:Nx}
% \begin{macro}{\tlp_put_right:cc}
% \begin{macro}{\tlp_gput_right:Nn}
% \begin{macro}{\tlp_gput_right:No}
% \begin{macro}{\tlp_gput_right:cn}
% \begin{macro}{\tlp_gput_right:co}
% \begin{macro}{\tlp_gput_right:Nx}
%    These are variants of the functions above, but for adding tokens
%    to the right.
%    \begin{macrocode}
\def_long_new:Npn \tlp_put_right:Nn #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_set:Nx #1{\exp_not:o{#1}\exp_not:o{\l_exp_tlp}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_gput_right:Nn #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_gset:Nx #1{\exp_not:o{#1}\exp_not:o{\l_exp_tlp}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_put_right:No #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_set:Nx #1{\exp_not:o{#1}\exp_not:d{\l_exp_tlp}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long_new:Npn \tlp_gput_right:No #1#2{
  \tlp_set:Nn \l_exp_tlp{#2}
  \tlp_gset:Nx #1{\exp_not:o{#1}\exp_not:d{\l_exp_tlp}}
%<check> \chk_local_or_pref_global:N #1
}
\def_long:Npn \tlp_put_right:Nx #1#2{
  \tlp_set:Nx #1{\exp_not:o{#1}#2}
%<check> \chk_local_or_pref_global:N #1
}
\def_long:Npn \tlp_gput_right:Nx #1#2{
  \tlp_gset:Nx #1{\exp_not:o{#1}#2}
%<check> \chk_local_or_pref_global:N #1
}
\def_new:Npn \tlp_gput_right:cn {\exp_args:Nc \tlp_gput_right:Nn}
\def_new:Npn \tlp_gput_right:co {\exp_args:Nc \tlp_gput_right:No}
\def_new:Npn \tlp_put_right:cc {\exp_args:Ncc \tlp_put_right:Nn}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%
% \begin{macro}{\tlp_gset:Nc}
% \begin{macro}{\tlp_set:Nc}
%    These two functions are included because they are necessary in
%    Denys' implementations. The |:Nc| convention (see the expansion
%    module) is very unusual at first sight, but it works nicely
%    over all modules, so we would like to keep it.
%
%    Construct a control sequence on the fly from |#2| and save it in
%    |#1|.
%    \begin{macrocode}
\def_new:Npn \tlp_gset:Nc {
%<*check>
  \pref_global_chk:
%</check>
%<-check> \pref_global:D
  \tlp_set:Nc}
%    \end{macrocode}
%    |\pref_global_chk:| will turn the variable check in |\tlp_set:No|
%    into a  global check.
%    \begin{macrocode}
\def_new:Npn \tlp_set:Nc #1#2{\tlp_set:No #1{\cs:w#2\cs_end:}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% We also provide a few conditionals, both in expandable form (with
% |\c_true|) and in `brace-form', the latter are denoted by |TF| at the
% end, as explained elsewhere.
%
%
% \begin{macro}{\tlp_if_empty_p:N}
% \begin{macro}{\tlp_if_empty_p:c}
%   Returns |\c_true| iff the token list in the argument is empty.
%    \begin{macrocode}
\def_new:Npn \tlp_if_empty_p:N #1{
  \if_meaning:NN#1\c_empty_tlp \c_true \else: \c_false \fi:}
\def_new:Npn \tlp_if_empty_p:c {\exp_args:Nc\tlp_if_empty_p:N}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\tlp_if_empty:NTF}
% \begin{macro}{\tlp_if_empty:NT}
% \begin{macro}{\tlp_if_empty:NF}
% \begin{macro}{\tlp_if_empty:cTF}
% \begin{macro}{\tlp_if_empty:cT}
% \begin{macro}{\tlp_if_empty:cF}
%    These functions check whether the token list in the argument is
%    empty and execute the proper code from their argument(s).
%    \begin{macrocode}
\def_test_function_new:npn {tlp_if_empty:N} #1{
  \if_meaning:NN#1\c_empty_tlp}
\def_new:Npn \tlp_if_empty:cTF {\exp_args:Nc \tlp_if_empty:NTF}
\def_new:Npn \tlp_if_empty:cT {\exp_args:Nc \tlp_if_empty:NT}
\def_new:Npn \tlp_if_empty:cF {\exp_args:Nc \tlp_if_empty:NF}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_if_eq_p:NN}
% \begin{macro}{\tlp_if_eq_p:Nc}
% \begin{macro}{\tlp_if_eq_p:cN}
% \begin{macro}{\tlp_if_eq_p:cc}
%   Returns |\c_true| iff the two token list pointers are equal.
%    \begin{macrocode}
\def_new:Npn \tlp_if_eq_p:NN #1#2{
  \if_meaning:NN#1#2 \c_true \else: \c_false \fi:}
\def_new:Npn \tlp_if_eq_p:Nc {\exp_args:NNc\tlp_if_empty_p:NN}
\def_new:Npn \tlp_if_eq_p:cN {\exp_args:Nc\tlp_if_empty_p:NN}
\def_new:Npn \tlp_if_eq_p:cc {\exp_args:Ncc\tlp_if_empty_p:NN}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_if_eq:NNTF}
% \begin{macro}{\tlp_if_eq:NNT}
% \begin{macro}{\tlp_if_eq:NNF}
% \begin{macro}{\tlp_if_eq:NcTF}
% \begin{macro}{\tlp_if_eq:NcT}
% \begin{macro}{\tlp_if_eq:NcF}
% \begin{macro}{\tlp_if_eq:cNTF}
% \begin{macro}{\tlp_if_eq:cNT}
% \begin{macro}{\tlp_if_eq:cNF}
% \begin{macro}{\tlp_if_eq:ccTF}
% \begin{macro}{\tlp_if_eq:ccT}
% \begin{macro}{\tlp_if_eq:ccF}
%   These function tests whether the token list pointers that are in its
%   first two arguments are equal.
%    \begin{macrocode}
\def_test_function_new:npn {tlp_if_eq:NN} #1#2{\if_meaning:NN#1#2}
\def_new:Npn \tlp_if_eq:cNTF{\exp_args:Nc \tlp_if_eq:NNTF}
\def_new:Npn \tlp_if_eq:cNT {\exp_args:Nc \tlp_if_eq:NNT}
\def_new:Npn \tlp_if_eq:cNF {\exp_args:Nc \tlp_if_eq:NNF}
\def_new:Npn \tlp_if_eq:NcTF{\exp_args:NNc \tlp_if_eq:NNTF}
\def_new:Npn \tlp_if_eq:NcT {\exp_args:NNc \tlp_if_eq:NNT}
\def_new:Npn \tlp_if_eq:NcF {\exp_args:NNc \tlp_if_eq:NNF}
\def_new:Npn \tlp_if_eq:ccTF{\exp_args:Ncc \tlp_if_eq:NNTF}
\def_new:Npn \tlp_if_eq:ccT {\exp_args:Ncc \tlp_if_eq:NNT}
\def_new:Npn \tlp_if_eq:ccF {\exp_args:Ncc \tlp_if_eq:NNF}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%
% \begin{macro}{\c_empty_tlp}
% \begin{macro}{\c_relax_tlp}
%    Two constants which are often used.
%    \begin{macrocode}
\tlp_new:Nn \c_empty_tlp {}
\tlp_new:Nn \c_relax_tlp {\scan_stop:}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \begin{macro}{\g_tmpa_tlp}
% \begin{macro}{\g_tmpb_tlp}
%    Global temporary token list pointers.
%    They are supposed to be set and used immediately,
%    with no delay between the definition and the use because you
%    can't count on other macros not to redefine them from under you.
%
%    \begin{macrocode}
\tlp_new:Nn \g_tmpa_tlp{}
\tlp_new:Nn \g_tmpb_tlp{}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\l_testa_tlp}
% \begin{macro}{\l_testb_tlp}
% \begin{macro}{\g_testa_tlp}
% \begin{macro}{\g_testb_tlp}
%    Global and local temporaries.  These are the ones for test
%    routines.  This means that one can safely use other temporaries
%    when calling test routines.
%    \begin{macrocode}
\tlp_new:Nn \l_testa_tlp {}
\tlp_new:Nn \l_testb_tlp {}
\tlp_new:Nn \g_testa_tlp {}
\tlp_new:Nn \g_testb_tlp {}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\l_tmpa_tlp}
% \begin{macro}{\l_tmpb_tlp}
%    These are local temporary token list pointers.
%    \begin{macrocode}
\tlp_new:Nn \l_tmpa_tlp{}
\tlp_new:Nn \l_tmpb_tlp{}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_to_str:N}
% \begin{macro}{\tlp_to_str:c}
% \begin{macro}{\tlp_to_str_aux:w}
%    These functions return the replacement text of a token list as a
%    string list with all characters catcoded to `other'.
%    \begin{macrocode}
\def_new:Npn \tlp_to_str:N {\exp_after:NN\tlp_to_str_aux:w
  \token_to_meaning:N}
\def_new:Npn \tlp_to_str_aux:w #1>{}
\def_new:Npn\tlp_to_str:c{\exp_args:Nc\tlp_to_str:N}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%
%
% \begin{macro}{\tlist_if_empty_p:n}
%   It would be tempting to just use "\if_meaning:NN\q_nil#1\q_nil" as
%   a test since this works really well. However it fails on a token
%   list starting with "\q_nil" of course but more troubling is the
%   case where argument is a complete conditional such as "\if_true:"
%   a "\else:" b "\fi:" because then "\if_true:" is used by
%   "\if_meaning:NN", the test turns out false, the "\else:" executes
%   the false branch, the "\fi:" ends it and the "\q_nil" at the end
%   starts executing\dots{} A safer route is to convert the entire
%   token list into harmless characters first and then compare
%   that. This way the test will even accept "\q_nil" as the first
%   token.
%    \begin{macrocode}
\def_long_new:Npn \tlist_if_empty_p:n #1{
  \exp_after:NN\if_meaning:NN\exp_after:NN\q_nil\tlist_to_str:n{#1}\q_nil
    \c_true
  \else:
    \c_false
  \fi:
}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\tlist_if_empty_p:o}
% \begin{macro}{\tlist_if_empty:nTF}
% \begin{macro}{\tlist_if_empty:nT}
% \begin{macro}{\tlist_if_empty:nF}
% \begin{macro}{\tlist_if_empty:oTF}
% \begin{macro}{\tlist_if_empty:oT}
% \begin{macro}{\tlist_if_empty:oF}
%    \begin{macrocode}
\def_new:Npn \tlist_if_empty_p:o {\exp_args:No\tlist_if_empty_p:n}
\def_long_test_function_new:npn{tlist_if_empty:n}#1{
  \if:w\tlist_if_empty_p:n{#1}}
\def_long_test_function_new:npn{tlist_if_empty:o}#1{
  \if:w\tlist_if_empty_p:o{#1}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlist_if_blank_p:n}
% \begin{macro}{\tlist_if_blank_p_aux:w}
%   This is based on the answers in ``Around the Bend No~2'' but is
%   safer as the tests listed there all have one small flaw: If the
%   input in the test is two tokens with the same meaning as the
%   internal delimiter, they will fail since one of them is mistaken
%   for the actual delimiter. In our version below we make sure to
%   pass the input through |\tlist_to_str:n| which ensures that all
%   the tokens are converted to catcode 12. However we use an |a| with
%   catcode 11 as delimiter so we can \emph{never} get into the same
%   problem as the solutions in ``Around the Bend No~2''.
%    \begin{macrocode}
\def_long_new:Npn \tlist_if_blank_p:n #1{
  \exp_after:NN\tlist_if_blank_p_aux:w\tlist_to_str:n{#1}aa..\q_nil     
}
\def_new:Npn \tlist_if_blank_p_aux:w #1#2a#3#4\q_nil{
  \if_meaning:NN #3#4\c_true\else:\c_false\fi:}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlist_if_blank:nTF}
% \begin{macro}{\tlist_if_blank:nT}
% \begin{macro}{\tlist_if_blank:nF}
% \begin{macro}{\tlist_if_blank_p:o}
% \begin{macro}{\tlist_if_blank:oTF}
% \begin{macro}{\tlist_if_blank:oT}
% \begin{macro}{\tlist_if_blank:oF}
% Variations on the original function above.
%    \begin{macrocode}
\def_long_test_function_new:npn{tlist_if_blank:n}#1{
  \if:w\tlist_if_blank_p:n{#1}}
\def:Npn \tlist_if_blank_p:o{\exp_args:No\tlist_if_blank_p:n}
\def_long_test_function_new:npn{tlist_if_blank:o}#1{
  \if:w\tlist_if_blank_p:o{#1}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlist_to_lowercase:n}
% \begin{macro}{\tlist_to_uppercase:n}
% Just some names for a few primitives.
%    \begin{macrocode}
\let_new:NN \tlist_to_lowercase:n \tex_lowercase:D
\let_new:NN \tlist_to_uppercase:n \tex_uppercase:D
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlist_to_str:n}
%   Another name for a primitive.
%    \begin{macrocode}
\let_new:NN \tlist_to_str:n \etex_detokenize:D
%    \end{macrocode}
% \end{macro}
%
%
%  \begin{macro}{\tlist_map_function:nN}
%  \begin{macro}{\tlp_map_function:NN}
%  \begin{macro}{\tlp_map_function:cN}
%  \begin{macro}{\tlist_map_function_aux:NN}
%  Expandable loop macro for |tlist|s. These have the advantage of not
%  needing to test if the argument is empty, because if it is, the stop
%  marker will be read immediately and the loop terminated.
%    \begin{macrocode}
\def_long_new:Npn \tlist_map_function:nN #1#2{
  \tlist_map_function_aux:Nn #2 #1 \q_recursion_tail \q_recursion_stop
}
\def_new:Npn \tlp_map_function:NN #1#2{
  \exp_after:NN \tlist_map_function_aux:Nn
  \exp_after:NN #2 #1 \q_recursion_tail \q_recursion_stop
}
\def_long_new:Npn \tlist_map_function_aux:Nn #1#2{
  \quark_if_recursion_tail_stop:n{#2} 
  #1{#2} \tlist_map_function_aux:Nn  #1 
}
\def_new:Npn\tlp_map_function:cN{\exp_args:Nc\tlp_map_function:NN}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%
%  \begin{macro}{\tlist_map_inline:nn}
%  \begin{macro}{\tlp_map_inline:Nn}
%  \begin{macro}{\tlp_map_inline:cn}
%  \begin{macro}{\tlist_map_inline_aux:n}
%  \begin{macro}{\g_tlp_inline_level_num}
%    The inline functions are straight forward by now. We use a little
%    a trick with the fake counter |\g_tlp_inline_level_num| to make
%    them nestable.\footnote{This should be a proper integer, but I
%      don't want to mess with the dependencies right now\dots} We can
%    also make use of |\tlist_map_function:Nn| from before.
%    \begin{macrocode}
\def_long_new:Npn \tlist_map_inline:nn #1#2{
  \num_gincr:N \g_tlp_inline_level_num
  \gdef_long:cpn {tlist_map_inline_ \num_use:N \g_tlp_inline_level_num :n}
  ##1{#2}
  \exp_args:Nc \tlist_map_function_aux:Nn
  {tlist_map_inline_ \num_use:N \g_tlp_inline_level_num :n}
  #1 \q_recursion_tail\q_recursion_stop
  \num_gdecr:N \g_tlp_inline_level_num
}
\def_long_new:Npn \tlp_map_inline:Nn #1#2{
  \num_gincr:N \g_tlp_inline_level_num
  \gdef_long:cpn {tlist_map_inline_ \num_use:N \g_tlp_inline_level_num :n}
  ##1{#2}
  \exp_args:NcE \tlist_map_function_aux:Nn 
  {tlist_map_inline_ \num_use:N \g_tlp_inline_level_num :n}
  #1 \q_recursion_tail\q_recursion_stop
  \num_gdecr:N \g_tlp_inline_level_num
}
\def_new:Npn\tlp_map_inline:cN{\exp_args:Nc\tlp_map_inline:NN}
\tlp_new:Nn \g_tlp_inline_level_num{0}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%
% \begin{macro}{\tlist_map_variable:nNn}
% \begin{macro}{\tlp_map_variable:NNn}
% \begin{macro}{\tlp_map_variable:cNn}
%    |\tlist_map:nNn| \zz{tlist} \zz{temp} \zz{action} assigns
%    \zz{temp} to each element and executes \zz{action}.
%    \begin{macrocode}
\def_long_new:Npn \tlist_map_variable:nNn #1#2#3{
  \tlist_map_variable_aux:Nnn #2 {#3} #1 \q_recursion_tail \q_recursion_stop
}
\def_new:Npn \tlp_map_variable:NNn {\exp_args:No \tlist_map_variable:nNn}
\def_new:Npn \tlp_map_variable:cNn {\exp_args:Nc \tlp_map_variable:NNn}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlist_map_variable_aux:NnN}
%  The general loop. Assign the temp variable |#1| to the current item
%  |#3| and then check if that's the stop marker. If it is, break the
%  loop. If not, execute the action |#2| and continue.
%    \begin{macrocode}
\def_long_new:Npn \tlist_map_variable_aux:Nnn #1#2#3{
  \tlp_set:Nn #1{#3}
  \quark_if_recursion_tail_stop:N #1 
  #2 \tlist_map_variable_aux:Nnn #1{#2} 
}
%    \end{macrocode}
% \end{macro}
%
%  \begin{macro}{\tlist_map_break:w}
%  \begin{macro}{\tlp_map_break:w}
%  The break statement.
%    \begin{macrocode}
\let_new:NN \tlist_map_break:w \use_none_delimit_by_q_recursion_stop:w
\let_new:NN \tlp_map_break:w \tlist_map_break:w
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%
%
%  \begin{macro}{\tlist_elt_count:n}
%  \begin{macro}{\tlist_elt_count:o}
%  \begin{macro}{\tlp_elt_count:n}
%    Count number of elements within a token list or token list
%    pointer. Brace groups within the list are read as a single
%    element.
%    "\num_elt_count:n" grabs the element and replaces it by "+1". The
%    "0" to ensure it works on an empty list.
%    \begin{macrocode}
\def_long_new:Npn \tlist_elt_count:n #1{
  \num_value:w \num_eval:w  0
  \tlist_map_function:nN {#1}\num_elt_count:n
  \num_eval_end:
}
\def_new:Npn \tlist_elt_count:o {\exp_args:No\tlist_elt_count:n}
\def_new:Npn \tlp_elt_count:N #1{
  \num_value:w \num_eval:w  0
  \tlp_map_function:NN #1 \num_elt_count:n
  \num_eval_end:
}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%
%
%
% \begin{macro}{\tlist_if_eq:nnTF}
% \begin{macro}{\tlist_if_eq:nnT}
% \begin{macro}{\tlist_if_eq:nnF}
%   Test if two token lists are identical. pdf\TeX\ contains a most
%   interesting primitive for expandable string comparison so we make
%   use of it if available. Presumable it will be in the final
%   version.
%
%   Firstly we give it an appropriate name. Note that this primitive
%   actually performs an \texttt{x} type expansion but it is still
%   expandable! Hence we must program these functions backwards to add
%   \verb|\exp_not:n|. We provide the combinations for the types
%   \texttt{n}, \texttt{o} and \texttt{x}.
%    \begin{macrocode}
\let_new:NN \tlist_compare:xx \pdfstrcmp
\def_long_new:NNn \tlist_compare:nn 2{
  \tlist_compare:xx{\exp_not:n{#1}}{\exp_not:n{#2}}
}
\def_long_new:NNn \tlist_compare:nx 1{
  \tlist_compare:xx{\exp_not:n{#1}}
}
\def_long_new:NNn \tlist_compare:xn 2{
  \tlist_compare:xx{#1}{\exp_not:n{#2}}
}
\def_long_new:NNn \tlist_compare:no 2{
  \tlist_compare:xx{\exp_not:n{#1}}{\exp_not:n\exp_after:NN{#2}}
}
\def_long_new:NNn \tlist_compare:on 2{
  \tlist_compare:xx{\exp_not:n\exp_after:NN{#1}}{\exp_not:n{#2}}
}
\def_long_new:NNn \tlist_compare:oo 2{
  \tlist_compare:xx{\exp_not:n\exp_after:NN{#1}}{\exp_not:n\exp_after:NN{#2}}
}
\def_long_new:NNn \tlist_compare:xo 2{
  \tlist_compare:xx{#1}{\exp_not:n\exp_after:NN{#2}}
}
\def_long_new:NNn \tlist_compare:ox 2{
  \tlist_compare:xx{\exp_not:n\exp_after:NN{#1}}{\exp_not:n{#2}}
}
%    \end{macrocode}
% Since we have a lot of basically identical functions to define we
% define one to define the rest. Unfortunately we aren't quite set up
% to use the new \verb|\tlist_map_inline:nn| function yet.
%    \begin{macrocode}
\def:Npn \tmp:w #1{
  \def_long_new:cNx {tlist_if_eq_p:#1} 2{
    \exp_not:N \if_num:w 
    \exp_after:NN \exp_not:N \cs:w tlist_compare:#1\cs_end:{##1}{##2}
    \exp_not:n{ =\c_zero \c_true \else: \c_false \fi: }
  }
  \def_long_test_function_new:npx{tlist_if_eq:#1}##1##2{
    \exp_not:N \if_num:w 
    \exp_after:NN \exp_not:N \cs:w tlist_compare:#1\cs_end:{##1}{##2}
    \exp_not:n{ =\c_zero }
  }
}
\tmp:w{xx}  \tmp:w{nn}  \tmp:w{oo}  \tmp:w{xn}  \tmp:w{nx}
\tmp:w{on}  \tmp:w{no}  \tmp:w{xo}  \tmp:w{ox}  
%    \end{macrocode}
% However all of this only makes sense if we actually have that
% primitive. Therefore we disable it again if it is not there and
% define \verb|\tlist_if_eq:nn| the old fashioned (and unexpandable)
% way.
%    \begin{macrocode}
\cs_if_really_free:cT{pdf_strcmp:D}{
  \def_long_test_function:npn{tlist_if_eq:nn}#1#2{
    \tlp_set:Nx \l_testa_tlp {\exp_not:n{#1}}
    \tlp_set:Nx \l_testb_tlp {\exp_not:n{#2}}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:no}#1#2{
    \tlp_set:Nx \l_testa_tlp {\exp_not:n{#1}}
    \tlp_set:Nx \l_testb_tlp {\exp_not:o{#2}}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:nx}#1#2{
    \tlp_set:Nx \l_testa_tlp {\exp_not:n{#1}}
    \tlp_set:Nx \l_testb_tlp {#2}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:on}#1#2{
    \tlp_set:Nx \l_testa_tlp {\exp_not:o{#1}}
    \tlp_set:Nx \l_testb_tlp {\exp_not:n{#2}}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:oo}#1#2{
    \tlp_set:Nx \l_testa_tlp {\exp_not:o{#1}}
    \tlp_set:Nx \l_testb_tlp {\exp_not:o{#2}}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:ox}#1#2{
    \tlp_set:Nx \l_testa_tlp {\exp_not:o{#1}}
    \tlp_set:Nx \l_testb_tlp {#2}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:xn}#1#2{
    \tlp_set:Nx \l_testa_tlp {#1}
    \tlp_set:Nx \l_testb_tlp {\exp_not:n{#2}}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:xo}#1#2{
    \tlp_set:Nx \l_testa_tlp {#1}
    \tlp_set:Nx \l_testb_tlp {\exp_not:o{#2}}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
  \def_long_test_function:npn{tlist_if_eq:xx}#1#2{
    \tlp_set:Nx \l_testa_tlp {#1}
    \tlp_set:Nx \l_testb_tlp {#2}
    \if_meaning:NN\l_testa_tlp \l_testb_tlp
  }
}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%
%
% \subsubsection{Checking for and replacing tokens}
%
% \begin{macro}{\tlp_if_in:NnTF}
% \begin{macro}{\tlp_if_in:cnTF}
% \begin{macro}{\tlp_if_in:NnT}
% \begin{macro}{\tlp_if_in:cnT}
% \begin{macro}{\tlp_if_in:NnF}
% \begin{macro}{\tlp_if_in:cnF}
% \begin{macro}{\tlist_if_in:nnTF}
% \begin{macro}{\tlist_if_in:onTF}
%   See the replace functions for further comments. In this part we
%   don't care too much about brace stripping since we are not
%   interested in passing on the tokens which are split off in the
%   process.
%    \begin{macrocode}
\def_long:Npn \tlp_if_in:NnTF #1#2{
  \def_long:Npn\tmp:w ##1 #2 ##2\q_stop{
    \quark_if_no_value:nFT{##2}
  }
  \exp_after:NN \tmp:w #1 #2 \q_no_value \q_stop
}
\def_new:Npn \tlp_if_in:cnTF {\exp_args:Nc\tlp_if_in:NnTF}
\def_long:Npn \tlp_if_in:NnT #1#2{
  \def_long:Npn\tmp:w ##1 #2 ##2\q_stop{
    \quark_if_no_value:nF{##2}
  }
  \exp_after:NN \tmp:w #1 #2 \q_no_value \q_stop
}
\def_new:Npn \tlp_if_in:cnT {\exp_args:Nc\tlp_if_in:NnT}
\def_long:Npn \tlp_if_in:NnF #1#2{
  \def_long:Npn\tmp:w ##1 #2 ##2\q_stop{
    \quark_if_no_value:nT{##2}
  }
  \exp_after:NN \tmp:w #1 #2 \q_no_value \q_stop
}
\def_new:Npn \tlp_if_in:cnF {\exp_args:Nc\tlp_if_in:NnF}
\def_long_new:Npn \tlist_if_in:nnTF #1#2{
  \def_long:Npn\tmp:w ##1 #2 ##2\q_stop{
    \quark_if_no_value:nFT{##2}
  }
  \tmp:w #1 #2 \q_no_value \q_stop
}
\def_new:Npn \tlist_if_in:onTF {\exp_args:No\tlist_if_in:nnTF}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\l_tlp_replace_tlp}
% A temp variable for the replace operations.
%    \begin{macrocode}
\tlp_new:Nn\l_tlp_replace_tlp{}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\tlp_replace_in:Nnn}
% \begin{macro}{\tlp_replace_in:cnn}
% \begin{macro}{\tlp_greplace_in:Nnn}
% \begin{macro}{\tlp_greplace_in:cnn}
% \begin{macro}{\tlp_replace_in_aux:NNnn}
%   Replacing the first item in a token list pointer goes like this:
%   Define a temporary function with delimited arguments containing
%   the search term and take a closer look at what is left. We append
%   the expansion of the tlp with the search term plus the quark
%   |\q_no_value|. If the search term isn't present this last one is
%   found and the following token is the quark, so we test for
%   that. If the search term is present we will have to split off the
%   |#3\q_no_value| we had, so we define yet another function with
%   delimited arguments to do this. The advantage here is that now we
%   have a special end sequence so there is no problem if the search
%   term appears more than once. Only problem left is to prevent brace
%   stripping in both ends, so we prepend the expansion of the tlp
%   with |\q_mark| later to be gobbled and also prepend the remainder
%   of the first split operation with |\q_mark| also to be gobbled
%   again later on.
%    \begin{macrocode}
\def_long_new:NNn \tlp_replace_in_aux:NNnn 4{
  \def_long:Npn \tmp:w ##1#3##2\q_stop{
    \quark_if_no_value:nF{##2}
    {
%    \end{macrocode}
% At this point |##1| starts with a |\q_mark| so remove it.
%    \begin{macrocode}
      \tlp_set:Nx\l_tlp_replace_tlp{\exp_not:o{\use_none:n##1#4}}
      \def_long:Npn \tmp:w ####1#3\q_no_value{
        \tlp_put_right:Nx \l_tlp_replace_tlp {\exp_not:o{\use_none:n ####1}}
      }
      \tmp:w \q_mark ##2
    }
%    \end{macrocode}
% Now all that is done is setting the token list pointer equal to the
% expansion of the token register.
%    \begin{macrocode}
    #1#2\l_tlp_replace_tlp
  }
%    \end{macrocode}
% Here is where we start the process. Note that the tlp might start
% with a space token so we use this little trick with |\use_arg_i:n|
% to prevent it from being removed.
%    \begin{macrocode}
  \use_arg_i:n{\exp_after:NN \tmp:w\exp_after:NN\q_mark}
  #2#3 \q_no_value\q_stop
}
%    \end{macrocode}
% Now the various versions doing the replacement either globally or
% locally.
%    \begin{macrocode}
\def_new:Npn \tlp_replace_in:Nnn {\tlp_replace_in_aux:NNnn \tlp_set_eq:NN}
\def_new:Npn \tlp_replace_in:cnn{\exp_args:Nc\tlp_replace_in:Nnn}
\def_new:Npn \tlp_greplace_in:Nnn {\tlp_replace_in_aux:NNnn \tlp_gset_eq:NN}
\def_new:Npn \tlp_greplace_in:cnn{\exp_args:Nc\tlp_greplace_in:Nnn}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tlp_replace_all_in:Nnn}
% \begin{macro}{\tlp_greplace_all_in:cnn}
% \begin{macro}{\tlp_replace_all_in:Nnn}
% \begin{macro}{\tlp_greplace_all_in:cnn}
% \begin{macro}{\tlp_replace_all_in_aux:NNnn}
%   The version for replacing \emph{all} occurrences of the search
%   term is fairly easy since we just have to keep doing the
%   replacement on the split-off part until all are
%   replaced. Otherwise it is pretty much the same as above.
%    \begin{macrocode}
\def_long:NNn \tlp_replace_all_in_aux:NNnn 4{
  \tlp_clear:N \l_tlp_replace_tlp
  \def_long:Npn \tmp:w ##1#3##2\q_stop{
    \quark_if_no_value:nTF{##2}
    { 
      \tlp_put_right:Nx \l_tlp_replace_tlp {\exp_not:o{\use_none:n##1}} 
    }
    { 
      \tlp_put_right:Nx \l_tlp_replace_tlp {\exp_not:o{\use_none:n##1 #4}} 
      \tmp:w \q_mark##2 \q_stop
    }
  }
  \use_arg_i:n{\exp_after:NN \tmp:w\exp_after:NN\q_mark} 
  #2#3 \q_no_value\q_stop
  #1#2\l_tlp_replace_tlp
}
%    \end{macrocode}
% Now the various forms.
%    \begin{macrocode}
\def_new:Npn \tlp_replace_all_in:Nnn {
  \tlp_replace_all_in_aux:NNnn \tlp_set_eq:NN}
\def_new:Npn \tlp_replace_all_in:cnn{\exp_args:Nc\tlp_replace_all_in:Nnn}
\def_new:Npn \tlp_greplace_all_in:Nnn {
  \tlp_replace_all_in_aux:NNnn \tlp_gset_eq:NN}
\def_new:Npn \tlp_greplace_all_in:cnn{\exp_args:Nc\tlp_greplace_all_in:Nnn}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%
% \begin{macro}{\tlp_remove_in:Nn}
% \begin{macro}{\tlp_remove_in:cn}
% \begin{macro}{\tlp_gremove_in:Nn}
% \begin{macro}{\tlp_gremove_in:cn}
%   Next comes a series of removal functions. I have just implemented
%   them as subcases of the replace functions for now (I'm lazy).
%    \begin{macrocode}
\def_long_new:NNn \tlp_remove_in:Nn  2{\tlp_replace_in:Nnn #1{#2}{}}
\def_long_new:NNn \tlp_gremove_in:Nn 2{\tlp_greplace_in:Nnn #1{#2}{}}
\def_new:Npn \tlp_remove_in:cn{\exp_args:Nc\tlp_remove_in:Nn}
\def_new:Npn \tlp_gremove_in:cn{\exp_args:Nc\tlp_gremove_in:Nn}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\tlp_remove_all_in:Nn}
% \begin{macro}{\tlp_remove_all_in:Nn}
% \begin{macro}{\tlp_gremove_all_in:Nn}
% \begin{macro}{\tlp_gremove_all_in:Nn}
%   Same old, same old.
%    \begin{macrocode}
\def_long_new:Npn \tlp_remove_all_in:Nn #1#2{
  \tlp_replace_all_in:Nnn #1{#2}{}
}
\def_long_new:Npn \tlp_gremove_all_in:Nn #1#2{
  \tlp_greplace_all_in:Nnn #1{#2}{}
}
\def_new:Npn \tlp_remove_all_in:cn{\exp_args:Nc\tlp_remove_all_in:Nn}
\def_new:Npn \tlp_gremove_all_in:cn{\exp_args:Nc\tlp_gremove_all_in:Nn}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%  \subsubsection{Heads or tails?}
%
%  \begin{macro}{\tlist_head:n}
%  \begin{macro}{\tlist_head_i:n}
%  \begin{macro}{\tlist_tail:n}
%  \begin{macro}{\tlist_tail:f}
%  \begin{macro}{\tlist_head_iii:n}
%  \begin{macro}{\tlist_head_iii:f}
%  \begin{macro}{\tlist_head:w}
%  \begin{macro}{\tlist_tail:w}
%  \begin{macro}{\tlist_head_iii:w}
%  These functions pick up either the head or the tail of a list.
%  "\tlist_head_iii:n" returns the first three items on a list.
%    \begin{macrocode}
\def_long_new:Npn \tlist_head:n #1{\tlist_head:w #1\q_nil}
\let_new:NN \tlist_head_i:n \tlist_head:n
\def_long_new:Npn \tlist_tail:n #1{\tlist_tail:w #1\q_nil}
\def_new:Npn \tlist_tail:f {\exp_args:Nf \tlist_tail:n}
\def_long_new:Npn \tlist_head_iii:n #1{\tlist_head_iii:w #1\q_nil}
\def_new:Npn \tlist_head_iii:f {\exp_args:Nf \tlist_head_iii:n}
\let_new:NN \tlist_head:w \use_arg_i_delimit_by_q_nil:nw
\def_long_new:Npn \tlist_tail:w #1#2\q_nil{#2}
\def_long_new:Npn \tlist_head_iii:w #1#2#3#4\q_nil{#1#2#3}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%  \begin{macro}{\tlist_if_head_eq_meaning_p:nN}
%  \begin{macro}{\tlist_if_head_eq_meaning:nNTF}
%  \begin{macro}{\tlist_if_head_eq_meaning:nNT}
%  \begin{macro}{\tlist_if_head_eq_meaning:nNF}
%  \begin{macro}{\tlist_if_head_eq_charcode_p:nNTF}
%  \begin{macro}{\tlist_if_head_eq_charcode:nNTF}
%  \begin{macro}{\tlist_if_head_eq_charcode:nNT}
%  \begin{macro}{\tlist_if_head_eq_charcode:nNF}
%  \begin{macro}{\tlist_if_head_eq_catcode_p:nNTF}
%  \begin{macro}{\tlist_if_head_eq_catcode:nNTF}
%  \begin{macro}{\tlist_if_head_eq_catcode:nNT}
%  \begin{macro}{\tlist_if_head_eq_catcode:nNF}
%  When we want to check if the first token of a list equals something
%  specific it is usually either to see if it is a control sequence or
%  a character. Hence we make two different functions as the internal
%  test is different.
%  |\tlist_if_head_meaning_eq:nNTF| uses |\if_meaning:NN| and will
%  consider the tokens |b|$\sb{11}$ and |b|$\sb{12}$ different.
%  |\tlist_if_head_char_eq:nNTF| on the other hand only compares
%  character codes so would regard |b|$\sb{11}$ and |b|$\sb{12}$ as
%  equal but would also regard two primitives as equal.
%    \begin{macrocode}
\def_long_new:Npn \tlist_if_head_eq_meaning_p:nN #1#2{
  \exp_after:NN \if_meaning:NN \tlist_head:w #1\q_nil#2
    \c_true
  \else:
    \c_false
  \fi:
}
\def_long_test_function_new:npn {tlist_if_head_eq_meaning:nN}#1#2{
  \if:w \tlist_if_head_eq_meaning_p:nN{#1}#2}
%    \end{macrocode}
% For the charcode and catcode versions we insert |\exp_not:N| in
% front of both tokens. If you need them to expand fully as \TeX{}
% does itself with these you can use an |f| type expansion.
%    \begin{macrocode}
\def_long_new:Npn \tlist_if_head_eq_charcode_p:nN #1#2{
   \exp_after:NN\if_charcode:w \exp_after:NN\exp_not:N
     \tlist_head:w #1\q_nil\exp_not:N#2
    \c_true
  \else:
    \c_false
  \fi:
}
\def_long_test_function_new:npn {tlist_if_head_eq_charcode:nN}#1#2{
  \if:w\tlist_if_head_eq_charcode_p:nN{#1}#2}
%    \end{macrocode}
% Actually the default is already an |f| type expansion.
%    \begin{macrocode}
\def_long_new:Npn \tlist_if_head_eq_charcode_p:fN #1#2{
   \exp_after:NN\if_charcode:w \tlist_head:w #1\q_nil\exp_not:N#2
    \c_true
  \else:
    \c_false
  \fi:
}
\def_long_test_function_new:npn {tlist_if_head_eq_charcode:fN}#1#2{
  \if:w\tlist_if_head_eq_charcode_p:fN{#1}#2}
\def_long_new:Npn \tlist_if_head_eq_catcode_p:nN #1#2{
   \exp_after:NN\if_charcode:w \exp_after:NN\exp_not:N
     \tlist_head:w #1\q_nil\exp_not:N#2
    \c_true
  \else:
    \c_false
  \fi:
}
\def_long_test_function_new:npn {tlist_if_head_eq_catcode:nN}#1#2{
  \if:w\tlist_if_head_eq_catcode_p:nN{#1}#2}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%
%  \begin{macro}{\tlist_reverse:n}
%  \begin{macro}{\tlist_reverse_aux:nN}
%    Reversal of a token list is done by taking one token at a time
%    and putting it in front of the ones before it.
%    \begin{macrocode}
\def_long_new:Npn \tlist_reverse:n #1{
   \tlist_reverse_aux:nN {} #1 \q_recursion_tail\q_recursion_stop
}
\def_long_new:Npn \tlist_reverse_aux:nN #1#2{
  \quark_if_recursion_tail_stop_do:nn {#2}{ #1 }
  \tlist_reverse_aux:nN {#2#1}
}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%
%
%
%  As this package relies heavily on a lot of the expansion tricks used
%  in \textsf{l3expan} we make sure to load it automatically at the end
%  when used as a package. Probably not needed but I'm just such a nice
%  guy\dots
%    \begin{macrocode}
%<package>\RequirePackage{l3expan}
%<package>\RequirePackage{l3num}\par
%    \end{macrocode}
%    Show token usage:
%    \begin{macrocode}
%</initex|package>
%<*showmemory>
\showMemUsage
%</showmemory>
%    \end{macrocode}
%
% \endinput
%
% $Log$
% Revision 1.28  2006/07/30 15:51:53  morten
% Made \tlist_map_inline:nn and variants nestable. Reimplemented
% \tlp_if_in:..., \tlp_replace_in:..., \tlp_replace_all_in:...
%
% Revision 1.27  2006/07/25 15:32:48  morten
% More \tlist_if_blank functions
%
% Revision 1.26  2006/07/06 14:58:50  morten
% Documentation touch-ups. Added more functions plus some new comparison
% functions which are dependent on a reasonably new pdfTeX.
%
% Revision 1.25  2006/06/05 14:55:14  morten
% Function for reversing a list of tokens.
%
% Revision 1.24  2006/06/03 16:31:19  morten
% Another version of \tlist_head...
%
% Revision 1.23  2006/03/20 18:26:41  braams
% Updated the copyright notice (2006) and demoted all implementation
% sections to subsections and so on to clean up the toc for source3.tex
%
% Revision 1.22  2006/01/26 14:00:42  morten
% Added a few missing functions (that were documented to be there!)
%
% Revision 1.21  2006/01/19 22:27:08  morten
% Added \tlp_replace_ and \tlp_remove_if_in functions.
%
% Revision 1.20  2006/01/17 23:07:06  morten
% Added "if_in" functions.
%
% Revision 1.19  2005/12/27 10:09:07  morten
% Changed RCS information retrieval, imported all tlist functions since
% half of them dealt with token list pointers anyway
%
% Revision 1.18  2005/07/25 19:50:40  morten
% Fixed the \long-ness aspects.
%
% Revision 1.17  2005/04/12 16:43:03  morten
% Minor updates
%
% Revision 1.16  2005/04/12 12:10:28  morten
% Rearranged and cleaned up code to avoid much doubling.
%
% Revision 1.15  2005/04/06 21:34:07  morten
% Fixed all tlp_set:XX so that they're \long. Added \tlp_set:Nf
%
% Revision 1.14  2005/03/22 23:20:43  morten
% Fixed \long versions according to Benjamin's suggestions. Slightly reorganized.
%
% Revision 1.13  2005/03/16 22:35:41  braams
% Added the tweaks necessary to be able to load with initex
%
% Revision 1.12  2005/03/11 21:43:58  braams
% Fixed the use of RCS information;
% Fixed a documentation typo
%