summaryrefslogtreecommitdiff
path: root/macros/generic/xstring/xstring-en.tex
blob: 94c46f9d3f5bfadafed6f549492b6a1ee022b0a4 (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
\documentclass[english,a4paper,10pt]{article}
\usepackage{fontspec}
\usepackage[bookmarks=true,bookmarksopen=true,colorlinks=true,hyperfootnotes=false,filecolor=black,linkcolor=blue,urlcolor=blue,pdfauthor={Christian Tellechea},pdftitle={xstring},pdfsubject={package for strings of tokens},pdfkeywords={xstring,latex,string},pdfcreator={LaTeX}]{hyperref}
\usepackage[margin=1.9cm]{geometry}
\usepackage{libertine}
\usepackage[scale=0.85]{noto-mono}
\usepackage[bottom]{footmisc}
\usepackage{amsmath,amssymb,amsfonts,color,eurosym,xspace,xstring,babel,listings}
\makeatletter
\definecolor{@xs@bckgcolor}{rgb}{0.9,1,1}
\definecolor{@xs@keywordsxstring}{rgb}{0,0,0.9}
\definecolor{@xs@keywordslatex}{rgb}{1,0,0}
\definecolor{@xs@arguments}{rgb}{0,0,0}
\definecolor{@xs@comments}{rgb}{0.5,0.5,0.5}
\definecolor{violet}{rgb}{0.66,0,0.66}
\lstset{%
	language=[AlLaTeX]TeX,%
	morekeywords={numexpr,detokenize},%
	float=hbp,%
	basicstyle=\small\ttfamily,%
	identifierstyle=\color{@xs@arguments},%
	keywordstyle=\color{@xs@keywordslatex},%
	commentstyle=\itshape\color{@xs@comments},%
	columns=fixed,%
	tabsize=4,%
	frame=single,%
	extendedchars=true,%
	showspaces=false,%
	showstringspaces=false,%
	numbers=left,%
	numberstyle=\tiny\ttfamily,%
	breaklines=true,%
	breakindent=3em,%
	backgroundcolor=\color{@xs@bckgcolor},%
	breakautoindent=true,%
	captionpos=t,%
	xleftmargin=1em,%
	xrightmargin=1em,%
	lineskip=0pt,%
	numbersep=1em,%
	classoffset=1,%
	morekeywords={% les macros et commandes de xstring
		IfSubStr,IfSubStrBefore,IfSubStrBehind,%
		IfBeginWith,IfEndWith,%
		IfInteger,IfDecimal,integerpart,decimalpart,%
		IfStrEq,IfEq,IfStrEqCase,IfEqCase,%
		StrBefore,StrBehind,StrCut,StrBetween,%
		StrSubstitute,StrDel,%
		StrGobbleLeft,StrGobbleRight,StrRight,StrLeft,StrMid,StrChar,%
		StrSplit,%
		StrLen,StrCount,StrPosition,StrCompare,%
		StrFindGroup,groupID,verbtocs,tokenize,scancs,StrExpand,StrRemoveBraces,%
		exploregroups,noexploregroups,saveexploremode,restoreexploremode,%
		comparenormal,comparestrict,savecomparemode,restorecomparemode,%
		expandarg,noexpandarg,normalexpandarg,fullexpandarg,saveexpandmode,restoreexpandmode,%
		expandingroups,noexpandingroups,%
		setverbdelim},%
	keywordstyle=\color{@xs@keywordsxstring},%
	classoffset=0}
\makeatother

\newcommand\guill[1]{"#1"}
\newcommand\argu[1]{$\langle$\textit{#1}$\rangle$}
\newcommand\ARGU[1]{\texttt{\{}\argu{#1}\texttt{\}}}
\newcommand\arguC[1]{\texttt{[}\argu{#1}\texttt{]}}
\newcommand\arguCC[2]{\texttt{[}\argu{#1}{,}\argu{#2}\texttt{]}}
\newcommand\texte[1]{\texttt{text}${}_{#1}$}
\newcommand\etoile{$\langle$\texttt{[*]}$\rangle$}
\newenvironment{Conditions}[1][1cm]%
{\begin{list}%
	{$\vartriangleright$}%
	{\setlength{\leftmargin}{#1}
	 \setlength{\itemsep}{0pt}
	 \setlength{\parsep}{0pt}
	 \setlength{\topsep}{2ptplus3ptminus2pt}
	}}%
{\end{list}}
\renewcommand\th{${}^\text{th}$\xspace}
\newcommand\US{syntax unit\xspace}
\newcommand\USs{syntax units\xspace}
\newcommand\Xstring{\textsf{xstring}\xspace}
\newcommand\styleexemple{\small\baselineskip1.03\baselineskip\vskip\baselineskip\relax}
\newcommand\styleexercice{\footnotesize}
\newcommand\verbinline{\lstinline[basicstyle=\normalsize\ttfamily]}
\newcommand\colorise{\color{violet}}
\def\xstringenglishdateaux#1/#2/#3\nil{\number#3\relax\space \ifcase #2 \or January\or February\or March\or April\or May\or June\or July\or August\or September\or October\or November\or December\fi\space#1}
\edef\xstringenglishdate{\expandafter\xstringenglishdateaux\xstringdate\nil}
\begin{document}
\setlength{\parindent}{0pt}
\begin{titlepage}
	\null\par\vfill
	\begin{center}
		\begin{minipage}{0.75\linewidth}
			\begin{center}
				\Huge\bfseries xstring\par\vspace{5pt}
				\small v\xstringversion\par\vspace{25pt}
				\normalsize User's manual
			\end{center}
		\end{minipage}
	\end{center}
	\vspace{1cm}
	\begin{center}
		Christian {\sc Tellechea}\par\small
		\href{mailto:unbonpetit@netc.fr}{\nolinkurl{unbonpetit@netc.fr}}\par\vspace{5pt}
		\xstringenglishdate
	\end{center}
	\vfill\hrulefill
	\begin{center}
		\begin{minipage}{0.85\linewidth}
			\noindent
			\hfill\textbf{\textit{Abstract}}\hfill{}\medskip\par
			This package which requires $\varepsilon$-\TeX{}, provides macros manipulating strings of tokens. For a basic use, tokens can be alphanumeric chars, but the macros can also be useful for manipulating tokens, i.e. \TeX{} code. Main features are:\smallskip

			\parindent1.5em
			\begin{itemize}
				\item[$\triangleright$] tests:
					\begin{itemize}
						\item does a string contains at least $n$ times an another?
						\item does a string starts (or ends) with another? etc.
						\item is a string an integer? A decimal?
						\item are 2 strings equal?
					\end{itemize}
				\item[$\triangleright$] extractions of substrings:
					\begin{itemize}
						\item what is on the left (or the right) of the $n$\th occurrence of a substring;
						\item what is between the occurrences of 2 substrings;
						\item substring between 2 positions;
						\item serach of a group with its identifier.
					\end{itemize}
				\item[$\triangleright$] substitution of all, or the $n$ first occurrences of a substring for an other substring;
				\item[$\triangleright$] calculation of numbers:
					\begin{itemize}
						\item length of a string;
						\item position of the $n$\th occurrence of a substring;
						\item how many times a string contains a substring?
						\item comparison of 2 strings: position of the first difference;
						\item identifier of the group in which a macro made a cut or a search.
					\end{itemize}
			\end{itemize}
			\parindent0pt
			\medskip
			Other macros allow to use special characters forbiden in arguments (\verb|#| and \verb|%|) and manage differences between catcodes for advanced programming purposes.
		\end{minipage}
	\end{center}
	\hrulefill\vfill{}
\end{titlepage}

\tableofcontents

This manual is a translation of the french manual. I apologize for my poor english but I did my best\footnote{Any email to tell me errors would be appreciated!}, and I hope that the following is comprehensible!
\section{Presentation}
\subsection{Description}
This extension\footnote{This extension does not require \LaTeX{} and can be compiled with Plain $\varepsilon$-\TeX{}.} provides macros and tests operating on "strings of tokens", as other programmation languages have. They provides the usual strings operations, such as: test if a string contains another, begins or ends with another, extractions of strings, calculation of the position of a substring, of the number of occurrences, etc.\medskip

A "string of tokens" is a list of tokens of any nature, except that braces must be balanced and tokens catcode 6 and 14 (usualy \verb|%| et \verb|#|) are not allowed. Apart from this, any token is allowed (including \verbinline|\par|), in any order in the list, whatever be the resulting code.\medskip

\Xstring reads the arguments of the macros \US by \US\footnote{In the \TeX{} code, a \US is a control sequence, a group between brace or a single char. See also page~\pageref{developpementarguments}.} : when \USs are \guill{simple} chars (catcode 10, 11 and 12), \Xstring logically read the argument char by char. \Xstring can also be used for programming purpose, including in arguments other tokens such as control sequences, braces and tokens with other catcodes. See chapter on reading mode and arguments expansion (page~\pageref{developpementarguments}), the command \verbinline|\verbtocs| (page~\pageref{verbtocs}) and the command \verbinline|\scancs| (page~\pageref{scancs}).\medskip

As the arguments may contain any token, advanced users could have problems with catcodes leading to unexpected behaviours. These behaviours can be controlled: read page~\pageref{macrosetoilees}.\medskip

Certainly, other packages exist (for example \href{http://mirror.ctan.org/tex-archive/macros/latex/contrib/substr/}{\nolinkurl{substr}} and \href{http://mirror.ctan.org/tex-archive/macros/latex/contrib/stringstrings/}{\nolinkurl{stringstrings}}), but as well as differences on features, they do not take into account occurrences so I found them too limited and difficult to use for programming.

\subsection{Motivation}
I decided to write this package of macros because I have never really found tools in \LaTeX{} suiting my needs for strings. So, over the last few months, I wrote a few macros that I occasionally or regularly used. Their numbers have increased and become a little too dispersed in directories in my computer, so I have grouped them together in this package.

Thus, writing a coherent set of macros forces more discipline and leads to necessary improvements, which took most of the time I spent writing this package. This package is my first one as I recently discoverd \LaTeX{}\footnote{In november 2007, I will be a noob for a long time\ldots}, so my main motivation was to make progress in programming with \TeX, and to tackle its specific methods.

\section{The macros}
For a better understanding, let's see first the macros with the simpler arguments possible. No special catcode, no exotic token, no control sequence neither: only alphanumeric chars will be contained in the arguments.\medskip

In the following chapters, all the macros will be presented this plan:
\begin{itemize}
	\item the syntax\footnote{The optional star, the optional argument in last position will be explained later. See page~\pageref{macrosetoilees} for starred macros and  page~\pageref{argumentoptionnel} for the optional argument.} and the value of optional arguments
	\item a short description of the operation;
	\item the operation under special conditions. For each conditions considered, the operation described has priority on that (those) below;
	\item finally, several examples\footnote{For much more examples, see the test file.} are given. I tried to find them most easily comprehensible and most representative of the situations met in normal use. If a doubt is possible with spaces in the result, this one will be delimited by \guill{|}, given that an empty string is represented by \guill{||}.
\end{itemize}\smallskip

\textbf{Important}: in the following, a \argu{number} can be an integer written with numeric chars, a counter, or the result of an arithmetic operation made with the command \verbinline|\numexpr|.\smallskip

All the macros of \Xstring are displayed in {\makeatletter\color{@xs@keywordsxstring}red}.

\subsection{The tests}
\subsubsection{\ttfamily\textbackslash IfSubStr}
\verbinline|\IfSubStr|\etoile\arguC{number}\ARGU{string}\ARGU{stringA}\ARGU{true}\ARGU{false}
\smallskip

The value of the optional argument \argu{number} is 1 by default.\par\smallskip

Tests if \argu{string} contains at least \argu{number} times \argu{stringA} and runs \argu{true} if so, and \argu{false} otherwise.\medskip

\begin{Conditions}
\item If \argu{number}${}\leqslant0$, runs \argu{false};
\item If \argu{string} or \argu{stringA} is empty, runs \argu{false}.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfSubStr{xstring}{tri}{true}{false}
\IfSubStr{xstring}{a}{true}{false}
\IfSubStr{a bc def }{c d}{true}{false}
\IfSubStr{a bc def }{cd}{true}{false}
\IfSubStr[2]{1a2a3a}{a}{true}{false}
\IfSubStr[3]{1a2a3a}{a}{true}{false}
\IfSubStr[4]{1a2a3a}{a}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfSubStr{xstring}{tri}{true}{false}\par
	\IfSubStr{xstring}{a}{true}{false}\par
	\IfSubStr{a bc def }{c d}{true}{false}\par
	\IfSubStr{a bc def }{cd}{true}{false}\par
	\IfSubStr[2]{1a2a3a}{a}{true}{false}\par
	\IfSubStr[3]{1a2a3a}{a}{true}{false}\par
	\IfSubStr[4]{1a2a3a}{a}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfSubStrBefore}
\verbinline|\IfSubStrBefore|\etoile\arguCC{number1}{number2}\ARGU{string}\ARGU{stringA}\ARGU{stringB}\ARGU{true}\ARGU{false}
\smallskip

The values of the optional arguments \argu{number1} and \argu{number2} are 1 by default.\par\smallskip

In \argu{string}, tests if the \argu{number1}\th occurrence of \argu{stringA} is on the left of the \argu{number2}\th occurrence of \argu{stringB}. Runs \argu{true} if so, and \argu{false} otherwise.\medskip

\begin{Conditions}
\item If one of the occurrences is not found, it runs \argu{false};
\item If one of the arguments \argu{string}, \argu{stringA} or \argu{stringB} is empty, runs \argu{false};
\item If one of the optional arguments is negative or zero, runs \argu{false}.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfSubStrBefore{xstring}{st}{in}{true}{false}
\IfSubStrBefore{xstring}{ri}{s}{true}{false}
\IfSubStrBefore{LaTeX}{LaT}{TeX}{true}{false}
\IfSubStrBefore{a bc def }{ b}{ef}{true}{false}
\IfSubStrBefore{a bc def }{ab}{ef}{true}{false}
\IfSubStrBefore[2,1]{b1b2b3}{b}{2}{true}{false}
\IfSubStrBefore[3,1]{b1b2b3}{b}{2}{true}{false}
\IfSubStrBefore[2,2]{baobab}{a}{b}{true}{false}
\IfSubStrBefore[2,3]{baobab}{a}{b}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfSubStrBefore{xstring}{st}{in}{true}{false}\par
	\IfSubStrBefore{xstring}{ri}{s}{true}{false}\par
	\IfSubStrBefore{LaTeX}{LaT}{TeX}{true}{false}\par
	\IfSubStrBefore{a bc def }{ b}{ef}{true}{false}\par
	\IfSubStrBefore{a bc def }{ab}{ef}{true}{false}\par
	\IfSubStrBefore[2,1]{b1b2b3}{b}{2}{true}{false}\par
	\IfSubStrBefore[3,1]{b1b2b3}{b}{2}{true}{false}\par
	\IfSubStrBefore[2,2]{baobab}{a}{b}{true}{false}\par
	\IfSubStrBefore[2,3]{baobab}{a}{b}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfSubStrBehind}

\verbinline|\IfSubStrBehind|\etoile\arguCC{number1}{number2}\ARGU{string}\ARGU{stringA}\ARGU{stringB}\ARGU{true}\ARGU{false}
\smallskip

The values of the optional arguments \argu{number1} and \argu{number2} are 1 by default.\par\smallskip

In \argu{string}, tests if the \argu{number1}\th occurrence of \argu{stringA} is on the right of the \argu{number2}\th occurrence of \argu{stringB}. Runs \argu{true} if so, and \argu{false} otherwise.\medskip

\begin{Conditions}
\item If one of the occurrences is not found, it runs \argu{false};
\item If one of the arguments \argu{string}, \argu{stringA} or \argu{stringB} is empty, runs \argu{false};
\item If one of the optional arguments is negative or zero, runs \argu{false}.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfSubStrBehind{xstring}{ri}{xs}{true}{false}
\IfSubStrBehind{xstring}{s}{i}{true}{false}
\IfSubStrBehind{LaTeX}{TeX}{LaT}{true}{false}
\IfSubStrBehind{a bc def }{ d}{a}{true}{false}
\IfSubStrBehind{a bc def }{cd}{a b}{true}{false}
\IfSubStrBehind[2,1]{b1b2b3}{b}{2}{true}{false}
\IfSubStrBehind[3,1]{b1b2b3}{b}{2}{true}{false}
\IfSubStrBehind[2,2]{baobab}{b}{a}{true}{false}
\IfSubStrBehind[2,3]{baobab}{b}{a}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfSubStrBehind{xstring}{ri}{xs}{true}{false}\par
	\IfSubStrBehind{xstring}{s}{i}{true}{false}\par
	\IfSubStrBehind{LaTeX}{TeX}{LaT}{true}{false}\par
	\IfSubStrBehind{a bc def }{ d}{a}{true}{false}\par
	\IfSubStrBehind{a bc def }{cd}{a b}{true}{false}\par
	\IfSubStrBehind[2,1]{b1b2b3}{b}{2}{true}{false}\par
	\IfSubStrBehind[3,1]{b1b2b3}{b}{2}{true}{false}\par
	\IfSubStrBehind[2,2]{baobab}{b}{a}{true}{false}\par
	\IfSubStrBehind[2,3]{baobab}{b}{a}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfBeginWith}

\verbinline|\IfBeginWith|\etoile\ARGU{string}\ARGU{stringA}\ARGU{true}\ARGU{false}
\smallskip

Tests if \argu{string} begins with \argu{stringA}, and runs \argu{true} if so, and \argu{false} otherwise.\medskip

\begin{Conditions}
\item If \argu{string} or \argu{stringA} is empty, runs \argu{false}.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfBeginWith{xstring}{xst}{true}{false}
\IfBeginWith{LaTeX}{a}{true}{false}
\IfBeginWith{a bc def }{a b}{true}{false}
\IfBeginWith{a bc def }{ab}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfBeginWith{xstring}{xst}{true}{false}\par
	\IfBeginWith{LaTeX}{a}{true}{false}\par
	\IfBeginWith{a bc def }{a b}{true}{false}\par
	\IfBeginWith{a bc def }{ab}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfEndWith}

\verbinline|\IfEndWith|\etoile\ARGU{string}\ARGU{stringA}\ARGU{Behind}\ARGU{false}
\smallskip

Tests if \argu{string} ends with \argu{stringA}, and runs \argu{true} if so, and \argu{false} otherwise.\medskip

\begin{Conditions}
\item If \argu{string} or \argu{stringA} is empty, runs \argu{false}.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfEndWith{xstring}{ring}{true}{false}
\IfEndWith{LaTeX}{a}{true}{false}
\IfEndWith{a bc def }{ef }{true}{false}
\IfEndWith{a bc def }{ef}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfEndWith{xstring}{ring}{true}{false}\par
	\IfEndWith{LaTeX}{a}{true}{false}\par
	\IfEndWith{a bc def }{ef }{true}{false}\par
	\IfEndWith{a bc def }{ef}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfInteger}

\verbinline|\IfInteger|\ARGU{number}\ARGU{true}\ARGU{false}
\smallskip

Tests if \argu{number} is an integer (i.e whose decimal part is empty or 0), and runs \argu{true} if so, and \argu{false} otherwise.\smallskip

If test is false because unexpected characters, the control sequence \verbinline|\@xs@afterinteger| and \verbinline|\afterinteger| both contain the illegal part of \argu{number}.\medskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfInteger{13}{true}{false}
\IfInteger{-219}{true}{false}
\IfInteger{+9}{true}{false}
\IfInteger{3.14}{true}{false}
\IfInteger{8.0}{true}{false}
\IfInteger{0}{true}{false}
\IfInteger{49a}{true}{false}
\IfInteger{+}{true}{false}
\IfInteger{-}{true}{false}
\IfInteger{0000}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfInteger{13}{true}{false}\par
	\IfInteger{-219}{true}{false}\par
	\IfInteger{+9}{true}{false}\par
	\IfInteger{3.14}{true}{false}\par
	\IfInteger{8.0}{true}{false}\par
	\IfInteger{0}{true}{false}\par
	\IfInteger{49a}{true}{false}\par
	\IfInteger{+}{true}{false}\par
	\IfInteger{-}{true}{false}\par
	\IfInteger{0000}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfDecimal}\label{ifdecimal}

\verbinline|\IfDecimal|\ARGU{number}\ARGU{true}\ARGU{false}
\smallskip

Tests if \argu{number} is a decimal, and runs \argu{true} if so, and \argu{false} otherwise.\smallskip

Counters \verbinline|\integerpart| and \verbinline|\decimalpart| contain the integer part and decimal part of \argu{number}.

If test is false because unexpected characters, the control sequence \verbinline|\@xs@afterdecimal| and \verb|\afterdecimal| both contain the illegal part of \argu{number}, whereas if test is false because decimal part is empty after decimal separator, they contain "X".\medskip

\begin{Conditions}
	\item Decimal separator can be a dot or a comma;
	\item If what is on the right of decimal separator (if it exists) is empty, the test is false;
	\item If what is on the left of decimal separator (if it exists) is empty, the integer part is assumed to be 0;
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfDecimal{3.14}{true}{false}
\IfDecimal{3,14}{true}{false}
\IfDecimal{-0.5}{true}{false}
\IfDecimal{.7}{true}{false}
\IfDecimal{,9}{true}{false}
\IfDecimal{1..2}{true}{false}
\IfDecimal{+6}{true}{false}
\IfDecimal{-15}{true}{false}
\IfDecimal{1.}{true}{false}
\IfDecimal{2,}{true}{false}
\IfDecimal{.}{true}{false}
\IfDecimal{,}{true}{false}
\IfDecimal{+}{true}{false}
\IfDecimal{-}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfDecimal{3.14}{true}{false}\par
	\IfDecimal{3,14}{true}{false}\par
	\IfDecimal{-0.5}{true}{false}\par
	\IfDecimal{.7}{true}{false}\par
	\IfDecimal{,9}{true}{false}\par
	\IfDecimal{1..2}{true}{false}\par
	\IfDecimal{+6}{true}{false}\par
	\IfDecimal{-15}{true}{false}\par
	\IfDecimal{1.}{true}{false}\par
	\IfDecimal{2,}{true}{false}\par
	\IfDecimal{.}{true}{false}\par
	\IfDecimal{,}{true}{false}\par
	\IfDecimal{+}{true}{false}\par
	\IfDecimal{-}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfStrEq}

\verbinline|\IfStrEq|\etoile\ARGU{stringA}\ARGU{stringB}\ARGU{true}\ARGU{false}
\smallskip

Tests if the strings \argu{stringA} and \argu{stringB} are equal, i.e. if they contain successively the same \USs in the same order. Runs \argu{true} if so, and \argu{false} otherwise.\smallskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfStrEq{a1b2c3}{a1b2c3}{true}{false}
\IfStrEq{abcdef}{abcd}{true}{false}
\IfStrEq{abc}{abcdef}{true}{false}
\IfStrEq{3,14}{3,14}{true}{false}
\IfStrEq{12.34}{12.340}{true}{false}
\IfStrEq{abc}{}{true}{false}
\IfStrEq{}{abc}{true}{false}
\IfStrEq{}{}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfStrEq{a1b2c3}{a1b2c3}{true}{false}\par
	\IfStrEq{abcdef}{abcd}{true}{false}\par
	\IfStrEq{abc}{abcdef}{true}{false}\par
	\IfStrEq{3,14}{3,14}{true}{false}\par
	\IfStrEq{12.34}{12.340}{true}{false}\par
	\IfStrEq{abc}{}{true}{false}\par
	\IfStrEq{}{abc}{true}{false}\par
	\IfStrEq{}{}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfEq}

\verbinline|\IfEq|\ARGU{stringA}\ARGU{stringB}\ARGU{true}\ARGU{false}
\smallskip

Tests if the strings \argu{stringA} and \argu{stringB} are equal, \emph{except} if both \argu{stringA} and \argu{stringB} contain numbers in which case the macro tests if these numbers are equal. Runs \argu{true} if so, and \argu{false} otherwise.\smallskip

\begin{Conditions}
	\item The definition of \emph{number} is given with the macro \verbinline|\IfDecimal| (see page~\pageref{ifdecimal}), and thus :
	\item \guill{+} signs are optional;
	\item Decimal separator can be a dot or a comma.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfEq{a1b2c3}{a1b2c3}{true}{false}
\IfEq{abcdef}{ab}{true}{false}
\IfEq{ab}{abcdef}{true}{false}
\IfEq{12.34}{12,34}{true}{false}
\IfEq{+12.34}{12.340}{true}{false}
\IfEq{10}{+10}{true}{false}
\IfEq{-10}{10}{true}{false}
\IfEq{+0,5}{,5}{true}{false}
\IfEq{1.001}{1.01}{true}{false}
\IfEq{3*4+2}{14}{true}{false}
\IfEq{\number\numexpr3*4+2}{14}{true}{false}
\IfEq{0}{-0.0}{true}{false}
\IfEq{}{}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfEq{a1b2c3}{a1b2c3}{true}{false}\par
	\IfEq{abcdef}{ab}{true}{false}\par
	\IfEq{ab}{abcdef}{true}{false}\par
	\IfEq{12.34}{12,34}{true}{false}\par
	\IfEq{+12.34}{12.340}{true}{false}\par
	\IfEq{10}{+10}{true}{false}\par
	\IfEq{-10}{10}{true}{false}\par
	\IfEq{+0,5}{,5}{true}{false}\par
	\IfEq{1.001}{1.01}{true}{false}\par
	\IfEq{3*4+2}{14}{true}{false}\par
	\IfEq{\number\numexpr3*4+2}{14}{true}{false}\par
	\IfEq{0}{-0.0}{true}{false}\par
	\IfEq{}{}{true}{false}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfStrEqCase}

\begin{minipage}{\textwidth}
	\verbinline|\IfStrEqCase|\etoile\ARGU{string}\verb|{%|\par
	\qquad\qquad\ARGU{string1}\ARGU{code1}\verb|%|\par
	\qquad\qquad\ARGU{string2}\ARGU{code2}\verb|%|\par
	\qquad\qquad\verb|etc...|\par
	\qquad\qquad\ARGU{stringN}\ARGU{codeN}\verb|}|\arguC{other cases code}
\end{minipage}
\smallskip

Tests successively if \argu{string} is equal to \argu{string1}, \argu{string2}, etc. Comparison is made with \verbinline|\IfStrEq| (see above). If the test number $i$ is positive (the \argu{string} matches \argu{string\;$i$}), the macro runs \argu{code\;$i$} and ends. If all tests fail, the macro runs the optional \argu{other cases code}, if present.\smallskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfStrEqCase{b}{{a}{AA}{b}{BB}{c}{CC}}
|\IfStrEqCase{abc}{{a}{AA}{b}{BB}{c}{CC}}|
\IfStrEqCase{c}{{a}{AA}{b}{BB}{c}{CC}}[other]
\IfStrEqCase{d}{{a}{AA}{b}{BB}{c}{CC}}[other]
\IfStrEqCase{+3}{{1}{one}{2}{two}{3}{three}}[other]
\IfStrEqCase{0.5}{{0}{zero}{.5}{half}{1}{one}}[other]
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfStrEqCase{b}{{a}{AA}{b}{BB}{c}{CC}}\par
	|\IfStrEqCase{abc}{{a}{AA}{b}{BB}{c}{CC}}|\par
	\IfStrEqCase{c}{{a}{AA}{b}{BB}{c}{CC}}[other]\par
	\IfStrEqCase{d}{{a}{AA}{b}{BB}{c}{CC}}[other]\par
	\IfStrEqCase{+3}{{1}{one}{2}{two}{3}{three}}[other]\par
	\IfStrEqCase{0.5}{{0}{zero}{.5}{half}{1}{one}}[other]
\end{minipage}%

\subsubsection{\ttfamily\textbackslash IfEqCase}

\begin{minipage}{\textwidth}
	\verbinline|\IfEqCase|\etoile\ARGU{string}\verb|{%|\par
	\qquad\qquad\ARGU{string1}\ARGU{code1}\verb|%|\par
	\qquad\qquad\ARGU{string2}\ARGU{code2}\verb|%|\par
	\qquad\qquad\verb|etc...|\par
	\qquad\qquad\ARGU{stringN}\ARGU{codeN}\verb|}|\arguC{other cases code}
\end{minipage}
\smallskip

Tests successively if \argu{string} is equal to \argu{string1}, \argu{string2}, etc. Comparison is made with \verbinline|\IEq| (see above). If the test number $i$ is positive (the \argu{string} matches \argu{string\;$i$}), the macro runs \argu{code\;$i$} and ends. If all tests fail, the macro runs the optional \argu{other cases code}, if present.\smallskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\IfEqCase{b}{{a}{AA}{b}{BB}{c}{CC}}
|\IfEqCase{abc}{{a}{AA}{b}{BB}{c}{CC}}|
\IfEqCase{c}{{a}{AA}{b}{BB}{c}{CC}}[other]
\IfEqCase{d}{{a}{AA}{b}{BB}{c}{CC}}[other]
\IfEqCase{+3}{{1}{one}{2}{two}{3}{three}}[other]
\IfEqCase{0.5}{{0}{zero}{.5}{half}{1}{one}}[other]
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\IfEqCase{b}{{a}{AA}{b}{BB}{c}{CC}}\par
	|\IfEqCase{abc}{{a}{AA}{b}{BB}{c}{CC}}|\par
	\IfEqCase{c}{{a}{AA}{b}{BB}{c}{CC}}[other]\par
	\IfEqCase{d}{{a}{AA}{b}{BB}{c}{CC}}[other]\par
	\IfEqCase{+3}{{1}{one}{2}{two}{3}{three}}[other]\par
	\IfEqCase{0.5}{{0}{zero}{.5}{half}{1}{one}}[other]
\end{minipage}%

\subsection{Extraction of substrings}
\subsubsection{\ttfamily\textbackslash StrBefore}

\verbinline|\StrBefore|\etoile\arguC{number}\ARGU{string}\ARGU{stringA}\arguC{name}
\smallskip

The value of the optional argument \argu{number} is 1 by default.\par\smallskip

In \argu{string}, returns what is leftwards the \argu{number}\th occurrence of \argu{stringA}.\medskip

\begin{Conditions}
\item If \argu{string} or \argu{stringA} is empty, an empty string is returned;
\item If \argu{number}${}<1$ then the macro behaves as if \argu{number}${}=1$;
\item If the occurrence is not found, an empty string is returned.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrBefore{xstring}{tri}
\StrBefore{LaTeX}{e}
|\StrBefore{LaTeX}{p}|
|\StrBefore{LaTeX}{L}|
|\StrBefore{a bc def }{def}|
|\StrBefore{a bc def }{cd}|
\StrBefore[1]{1b2b3}{b}
\StrBefore[2]{1b2b3}{b}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrBefore{xstring}{tri}\par
	\StrBefore{LaTeX}{e}\par
	|\StrBefore{LaTeX}{p}|\par
	|\StrBefore{LaTeX}{L}|\par
	|\StrBefore{a bc def }{def}|\par
	|\StrBefore{a bc def }{cd}|\par
	\StrBefore[1]{1b2b3}{b}\par
	\StrBefore[2]{1b2b3}{b}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrBehind}

\verbinline|\StrBehind|\etoile\arguC{number}\ARGU{string}\ARGU{stringA}\arguC{name}
\smallskip

The value of the optional argument \argu{number} is 1 by default.\par\smallskip

In \argu{string}, returns what is rightwards the \argu{number}\th occurrence of \argu{stringA}.\medskip

\begin{Conditions}
\item If \argu{string} or \argu{stringA} is empty, an empty string is returned;
\item If \argu{number}${}<1$ then the macro behaves as if \argu{number}${}=1$;
\item If the occurrence is not found, an empty string is returned.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrBehind{xstring}{tri}
\StrBehind{LaTeX}{e}
|\StrBehind{LaTeX}{p}|
|\StrBehind{LaTeX}{X}|
|\StrBehind{a bc def }{bc}|
|\StrBehind{a bc def }{cd}|
\StrBehind[1]{1b2b3}{b}
\StrBehind[2]{1b2b3}{b}
|\StrBehind[3]{1b2b3}{b}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrBehind{xstring}{tri}\par
	\StrBehind{LaTeX}{e}\par
	|\StrBehind{LaTeX}{p}|\par
	|\StrBehind{LaTeX}{X}|\par
	|\StrBehind{a bc def }{bc}|\par
	|\StrBehind{a bc def }{cd}|\par
	\StrBehind[1]{1b2b3}{b}\par
	\StrBehind[2]{1b2b3}{b}\par
	|\StrBehind[3]{1b2b3}{b}|
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrCut}
Here is the syntax of this macro:\par\nobreak\smallskip
\verbinline|\StrCut|\etoile\arguC{nunber}\ARGU{string}\ARGU{stringA}\ARGU{macroA}\ARGU{macroB}
\smallskip

The optional argument \argu{number} is 1 by default.\par\nobreak\smallskip
The \argu{string} is cut in two parts at the occurrence \arguC{number} of \ARGU{stringA}. The left part is stored in the control sequence \argu{macroA} and the right part in \argu{macroB}.

Since this macro returns \emph{two strings}, it does \emph{not} display anything. Consequently, it does not provide the optional argument in last position.\medskip

\begin{Conditions}
	\item If \argu{string} or \argu{stringA} is empty, \argu{macroA} and \argu{macroB} are empty;
	\item If \argu{number}${}<1$, the macro behaves as if \argu{number}${}=1$;
	\item If the occurrence is not found, \argu{macroA} receives the whole \argu{string} while \argu{macroB} is empty.
\end{Conditions}
\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrCut{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut[2]{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut[3]{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut[4]{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut[5]{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut[6]{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut[-4]{abracadabra}{a}\csA\csB |\csA|\csB|\par
\StrCut{abracadabra}{brac}\csA\csB |\csA|\csB|\par
\StrCut{abracadabra}{foo}\csA\csB |\csA|\csB|\par
\StrCut{abracadabra}{}\csA\csB |\csA|\csB|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\def\seprouge{{\color{red}|}}
	\styleexemple
	\StrCut{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut[2]{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut[3]{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut[4]{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut[5]{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut[6]{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut[-4]{abracadabra}{a}\csA\csB |\csA\seprouge\csB|\par
	\StrCut{abracadabra}{brac}\csA\csB |\csA\seprouge\csB|\par
	\StrCut{abracadabra}{foo}\csA\csB |\csA\seprouge\csB|\par
	\StrCut{abracadabra}{}\csA\csB |\csA\seprouge\csB|
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrBetween}

\verbinline|\StrBetween|\etoile\arguCC{number1}{number2}\ARGU{string}\ARGU{stringA}\ARGU{stringB}\arguC{name}
\smallskip

The values of the optional arguments \argu{number1} and \argu{number2} are 1 by default.\par\smallskip

In \argu{string}, returns the substring between\footnote{In a strict sense, i.e. \emph{without} the strings \argu{stringA} and \argu{stringB}} the \argu{number1}\th occurrence of \argu{stringA} and \argu{number2}\th occurrence of \argu{stringB}.\medskip

\begin{Conditions}
\item If the occurrences are not in this order ---~\argu{stringA} \emph{followed by} \argu{stringB}~--- in \argu{string}, an empty string is returned;
\item If one of the 2 occurrences doesn't exist in \argu{string}, an empty string is returned;
\item  If one of the optional arguments \argu{number1} ou \argu{number2} is negative or zero, an empty string is returned.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrBetween{xstring}{xs}{ng}
|\StrBetween{xstring}{i}{n}|
|\StrBetween{xstring}{a}{tring}|
|\StrBetween{a bc def }{a}{d}|
|\StrBetween{a bc def }{a }{f}|
\StrBetween{a1b1a2b2a3b3}{a}{b}
\StrBetween[2,3]{a1b1a2b2a3b3}{a}{b}
\StrBetween[1,3]{a1b1a2b2a3b3}{a}{b}
|\StrBetween[3,1]{a1b1a2b2a3b3}{a}{b}|
\StrBetween[3,2]{abracadabra}{a}{bra}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrBetween{xstring}{xs}{ng}\par
	|\StrBetween{xstring}{i}{n}|\par
	|\StrBetween{xstring}{a}{tring}|\par
	|\StrBetween{a bc def }{a}{d}|\par
	|\StrBetween{a bc def }{a }{f}|\par
	\StrBetween{a1b1a2b2a3b3}{a}{b}\par
	\StrBetween[2,3]{a1b1a2b2a3b3}{a}{b}\par
	\StrBetween[1,3]{a1b1a2b2a3b3}{a}{b}\par
	|\StrBetween[3,1]{a1b1a2b2a3b3}{a}{b}|\par
	\StrBetween[3,2]{abracadabra}{a}{bra}\par
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrSubstitute}

\verbinline|\StrSubstitute|\arguC{number}\ARGU{string}\ARGU{stringA}\ARGU{stringB}\arguC{name}
\smallskip

The value of the optional argument \argu{number} is 0 by default.\par\smallskip

In \argu{string}, substitute the \argu{number} first occurrences of \argu{stringA} for \argu{stringB}, except if \argu{number}${}=0$ in which case \emph{all} the occurrences are substituted.

\begin{Conditions}
\item If \argu{string} is empty, an empty string is returned;
\item If \argu{stringA} is empty or doesn't exist in \argu{string}, the macro is ineffective;
\item If \argu{number} is greater than the number of occurrences of \argu{stringA}, then all the occurrences are substituted;
\item If \argu{number}${}<0$ the macro behaves as if \argu{number}${}=0$;
\item If \argu{stringB} is empty, the occurrences of \argu{stringA}, if they exist, are deleted.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrSubstitute{xstring}{i}{a}
\StrSubstitute{abracadabra}{a}{o}
\StrSubstitute{abracadabra}{br}{TeX}
\StrSubstitute{LaTeX}{m}{n}
\StrSubstitute{a bc def }{ }{M}
\StrSubstitute{a bc def }{ab}{AB}
\StrSubstitute[1]{a1a2a3}{a}{B}
\StrSubstitute[2]{a1a2a3}{a}{B}
\StrSubstitute[3]{a1a2a3}{a}{B}
\StrSubstitute[4]{a1a2a3}{a}{B}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrSubstitute{xstring}{i}{a}\par
	\StrSubstitute{abracadabra}{a}{o}\par
	\StrSubstitute{abracadabra}{br}{TeX}\par
	\StrSubstitute{LaTeX}{m}{n}\par
	\StrSubstitute{a bc def }{ }{M}\par
	\StrSubstitute{a bc def }{ab}{AB}\par
	\StrSubstitute[1]{a1a2a3}{a}{B}\par
	\StrSubstitute[2]{a1a2a3}{a}{B}\par
	\StrSubstitute[3]{a1a2a3}{a}{B}\par
	\StrSubstitute[4]{a1a2a3}{a}{B}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrDel}

\verbinline|\StrDel|\etoile\arguC{number}\ARGU{string}\ARGU{stringA}\arguC{name}
\smallskip

The value of the optional argument \argu{number} is 0 by default.\par\smallskip

Delete the \argu{number} first occurrences of \argu{stringA} in \argu{string}, except if \argu{number}${}=0$ in which case \emph{all} the occurrences are deleted.\medskip

\begin{Conditions}
\item If \argu{string} is empty, an empty string is returned;
\item If \argu{stringA} is empty or doesn't exist in \argu{string}, the macro is ineffective;
\item If \argu{number} greater then the number of occurrences of \argu{stringA}, then all the occurrences are deleted;
\item If \argu{number}${}<0$ the macro behaves as if \argu{number}${}=0$;
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrDel{abracadabra}{a}
\StrDel[1]{abracadabra}{a}
\StrDel[4]{abracadabra}{a}
\StrDel[9]{abracadabra}{a}
\StrDel{a bc def }{ }
|\StrDel{a bc def }{def}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrDel{abracadabra}{a}\par
	\StrDel[1]{abracadabra}{a}\par
	\StrDel[4]{abracadabra}{a}\par
	\StrDel[9]{abracadabra}{a}\par
	\StrDel{a bc def }{ }\par
	|\StrDel{a bc def }{def}|
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrGobbleLeft}
\verbinline|\StrGobbleLeft|\ARGU{string}\ARGU{number}\arguC{name}
\smallskip

In \argu{string}, delete the \argu{number} first characters on the left.\medskip

\begin{Conditions}
\item If \argu{string} is empty, an empty string is returned;
\item If \argu{number}${}\leqslant0$, no character is deleted;
\item If \argu{number}${}\geqslant{}$\argu{lengthString}, all the characters are deleted.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrGobbleLeft{xstring}{2}
|\StrGobbleLeft{xstring}{9}|
\StrGobbleLeft{LaTeX}{4}
\StrGobbleLeft{LaTeX}{-2}
|\StrGobbleLeft{a bc def }{4}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrGobbleLeft{xstring}{2}\par
	|\StrGobbleLeft{xstring}{9}|\par
	\StrGobbleLeft{LaTeX}{4}\par
	\StrGobbleLeft{LaTeX}{-2}\par
	|\StrGobbleLeft{a bc def }{4}|
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrLeft}

\verbinline|\StrLeft|\ARGU{string}\ARGU{number}\arguC{name}
\smallskip

In \argu{string}, returns the \argu{number} first characters on the left.\medskip

\begin{Conditions}
\item If \argu{string} is empty, an empty string is returned;
\item If \argu{number}${}\leqslant0$, no character is returned;
\item If \argu{number}${}\geqslant{}$\argu{lengthString}, all the characters are returned.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrLeft{xstring}{2}
\StrLeft{xstring}{9}
\StrLeft{LaTeX}{4}
|\StrLeft{LaTeX}{-2}|
|\StrLeft{a bc def }{5}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrLeft{xstring}{2}\par
	\StrLeft{xstring}{9}\par
	\StrLeft{LaTeX}{4}\par
	|\StrLeft{LaTeX}{-2}|\par
	|\StrLeft{a bc def }{5}|
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrGobbleRight}

\verbinline|\StrGobbleRight|\ARGU{string}\ARGU{number}\arguC{name}
\smallskip

In \argu{string}, delete the \argu{number} last characters on the right.\medskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrGobbleRight{xstring}{2}
|\StrGobbleRight{xstring}{9}|
\StrGobbleRight{LaTeX}{4}
|\StrGobbleRight{LaTeX}{-2}|
|\StrGobbleRight{a bc def }{4}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrGobbleRight{xstring}{2}\par
	|\StrGobbleRight{xstring}{9}|\par
	\StrGobbleRight{LaTeX}{4}\par
	|\StrGobbleRight{LaTeX}{-2}|\par
	|\StrGobbleRight{a bc def }{4}|
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrRight}

\verbinline|\StrRight|\ARGU{string}\ARGU{number}\arguC{name}
\smallskip

In \argu{string}, returns the \argu{number} last characters on the right.\medskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrRight{xstring}{2}
\StrRight{xstring}{9}
\StrRight{LaTeX}{4}
|\StrRight{LaTeX}{-2}|
\StrRight{a bc def }{5}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrRight{xstring}{2}\par
	\StrRight{xstring}{9}\par
	\StrRight{LaTeX}{4}\par
	|\StrRight{LaTeX}{-2}|\par
	\StrRight{a bc def }{5}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrChar}

\verbinline|\StrChar|\etoile\ARGU{string}\ARGU{number}\arguC{name}
\smallskip

Returns the \US at the position \argu{number} in \argu{string}.\medskip

\begin{Conditions}
\item If \argu{string} is empty, no caracter is returned;
\item If \argu{number}${}\leqslant0$ or if \argu{number}${}>{}$\argu{lengthString}, no character is returned.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrChar{xstring}{4}
|\StrChar{xstring}{9}|
|\StrChar{xstring}{-5}|
\StrChar{a bc def }{6}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrChar{xstring}{4}\par
	|\StrChar{xstring}{9}|\par
	|\StrChar{xstring}{-5}|\par
	\StrChar{a bc def }{6}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrMid}

\verbinline|\StrMid|\ARGU{string}\ARGU{numberA}\ARGU{numberB}\arguC{name}
\smallskip

In \argu{string}, returns the substring between\footnote{In the broad sense, i.e. that the strings characters of the \guill{border} are returned.} the positions \argu{numberA} and \argu{numberB}.\medskip

\begin{Conditions}
\item If \argu{string} is empty, an empty string is returned;
\item If \argu{numberA}${}>{}$\argu{numberB}, an empty string is returned;
\item If \argu{numberA}${}<1$ and \argu{numberB}${}<1$ an empty string is returned;
\item If \argu{numberA}${}>{}$\argu{lengthString} et \argu{numberB}${}>{}$\argu{lengthString}, an empty string is returned;
\item If \argu{numberA}${}<1$, the macro behaves as if \argu{numberA}${}=1$;
\item If \argu{numberB}${}>{}$\argu{lengthString}, the macro behaves as if \argu{numberB}${}={}$\argu{lengthString}.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrMid{xstring}{2}{5}
\StrMid{xstring}{-4}{2}
|\StrMid{xstring}{5}{1}|
\StrMid{xstring}{6}{15}
\StrMid{xstring}{3}{3}
|\StrMid{a bc def }{2}{7}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrMid{xstring}{2}{5}\par
	\StrMid{xstring}{-4}{2}\par
	|\StrMid{xstring}{5}{1}|\par
	\StrMid{xstring}{6}{15}\par
	\StrMid{xstring}{3}{3}\par
	|\StrMid{a bc def }{2}{7}|
\end{minipage}%

\subsection{Macros returning a number}
\subsubsection{\ttfamily\textbackslash StrLen}

\verbinline|\StrLen|\ARGU{string}\arguC{name}
\smallskip

Return the length of \argu{string}.

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrLen{xstring}
\StrLen{A}
\StrLen{a bc def }
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrLen{xstring}\par
	\StrLen{A}\par
	\StrLen{a bc def }
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrCount}

\verbinline|\StrCount|\ARGU{string}\ARGU{stringA}\arguC{name}
\smallskip

Counts how many times \argu{stringA} is contained in \argu{string}.\par\medskip

\begin{Conditions}
\item If one at least of the arguments \argu{string} or \argu{stringA} is empty, the macro return 0.
\end{Conditions}

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrCount{abracadabra}{a}
\StrCount{abracadabra}{bra}
\StrCount{abracadabra}{tic}
\StrCount{aaaaaa}{aa}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrCount{abracadabra}{a}\par
	\StrCount{abracadabra}{bra}\par
	\StrCount{abracadabra}{tic}\par
	\StrCount{aaaaaa}{aa}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrPosition}

\verbinline|\StrPosition|\arguC{number}\ARGU{string}\ARGU{stringA}\arguC{name}
\smallskip

The value of the optional argument \argu{number} is 1 by default.\par\smallskip

In \argu{string}, returns the position of the \argu{number}\th occurrence of \argu{stringA}.\medskip

\begin{Conditions}
\item If \argu{number} is greater than the number of occurrences of \argu{stringA}, then the macro returns 0;
\item If \argu{string} doesn't contain \argu{stringA}, then the macro returns 0.
\end{Conditions}
\medskip

\begin{minipage}[t]{0.65\linewidth}
\begin{lstlisting}
\StrPosition{xstring}{ring}
\StrPosition[4]{abracadabra}{a}
\StrPosition[2]{abracadabra}{bra}
\StrPosition[9]{abracadabra}{a}
\StrPosition{abracadabra}{z}
\StrPosition{a bc def }{d}
\StrPosition[3]{aaaaaa}{aa}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\StrPosition{xstring}{ring}\par
	\StrPosition[4]{abracadabra}{a}\par
	\StrPosition[2]{abracadabra}{bra}\par
	\StrPosition[9]{abracadabra}{a}\par
	\StrPosition{abracadabra}{z}\par
	\StrPosition{a bc def }{d}\par
	\StrPosition[3]{aaaaaa}{aa}
\end{minipage}%

\subsubsection{\ttfamily\textbackslash StrCompare}
\verbinline|\StrCompare|\etoile\ARGU{stringA}\ARGU{stringB}\arguC{name}
\smallskip

This macro has 2 tolerances: the "normal" tolerance, used by default, and the "strict" tolerance.
\begin{itemize}
	\item The normal tolerance is activated with \verbinline|\comparenormal|.\par
	The macro compares characters from left to right in \argu{stringA} and \argu{stringB} until a difference appears or the end of the shortest string is reached. The position of the first difference is returned and if no difference is found, the macro return 0.
	\item The strict tolerance is activated with \verbinline|\comparestrict|.\par
	The macro compares the 2 strings. If they are equal, it returns 0. If not, the position of the first difference is returned.
\end{itemize}
\medskip

It is possible to save the comparison mode with \verbinline|\savecomparemode|, then modify this comparison mode and come back to the situation when it was saved with \verbinline|\restorecomparemode|.\medskip

Examples with the normal tolerance:\par\nobreak
\begin{minipage}[t]{0.65\linewidth}
\comparenormal
\begin{lstlisting}
\StrCompare{abcd}{abcd}
\StrCompare{abcd}{abc}
\StrCompare{abc}{abcd}
\StrCompare{a b c}{abc}
\StrCompare{aaa}{baaa}
\StrCompare{abc}{xyz}
\StrCompare{123456}{123457}
\StrCompare{abc}{}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\comparenormal
	\StrCompare{abcd}{abcd}\par
	\StrCompare{abcd}{abc}\par
	\StrCompare{abc}{abcd}\par
	\StrCompare{a b c}{abc}\par
	\StrCompare{aaa}{baaa}\par
	\StrCompare{abc}{xyz}\par
	\StrCompare{123456}{123457}\par
	\StrCompare{abc}{}
\end{minipage}%
\medskip

Examples with the strict tolerance:\par\nobreak
\begin{minipage}[t]{0.65\linewidth}
\comparestrict
\begin{lstlisting}
\StrCompare{abcd}{abcd}
\StrCompare{abcd}{abc}
\StrCompare{abc}{abcd}
\StrCompare{a b c}{abc}
\StrCompare{aaa}{baaa}
\StrCompare{abc}{xyz}
\StrCompare{123456}{123457}
\StrCompare{abc}{}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[t]{0.35\linewidth}
	\styleexemple
	\comparestrict
	\StrCompare{abcd}{abcd}\par
	\StrCompare{abcd}{abc}\par
	\StrCompare{abc}{abcd}\par
	\StrCompare{a b c}{abc}\par
	\StrCompare{aaa}{baaa}\par
	\StrCompare{abc}{xyz}\par
	\StrCompare{123456}{123457}\par
	\StrCompare{abc}{}
\end{minipage}%

\section{Operating modes}
\subsection{Expansion of arguments}
\label{devarg}
\subsubsection{The commands {\ttfamily \textbackslash fullexpandarg}, {\ttfamily \textbackslash expandarg} and {\ttfamily \textbackslash noexpandarg}}
The command \verbinline|\fullexpandarg| is called by default, so all the arguments are fully expanded (an \verbinline|\edef| is used) before the the macro works on them. In most of the cases, this expansion mode avoids chains of \verbinline|\expandafter| and allows lighter code.

Of course, the expansion of argument can be canceled to find back the usual behaviour of \TeX{} with the commands \verbinline|\noexpandarg| or \verbinline|\normalexpandarg|.\medskip

Another expansion mode can be called with \verbinline|\expandarg|. In this case, the \textbf{first token} of each argument is expanded \emph{one time} while all other tokens are left unchanged (if you want the expansion of all tokens one time, you should call the macro \verbinline|\StrExpand|, see page~\pageref{scancs}).\medskip

The commands \verbinline|\fullexpandarg|, \verbinline|\noexpandarg|, \verbinline|\normalexpandarg| and \verbinline|\expandarg| can be called at any moment in the code; they behave as "switches" and they can be locally used in a group.\medskip

It is possible to save the expansion mode with \verbinline|\saveexpandmode|, then modify this expansion mode and come back to the situation when it was saved with \verbinline|\restoreexpandmode|.\medskip

In the following list, for every macro of the previous chapter, the arguments colored in \textcolor{violet}{purple} will possibly be expanded, according to the expansion mode:\smallskip

\parindent3em
\begin{itemize}
	\item\verb|\IfSubStr|\etoile{\colorise\arguC{number}\ARGU{string}\ARGU{stringA}}\ARGU{true}\ARGU{false}
	\item\verb|\IfSubStrBefore|\etoile{\colorise\arguCC{number1}{number2}\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfSubStrBehind|\etoile{\colorise\arguCC{number1}{number2}\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfBeginWith|\etoile{\colorise\ARGU{string}\ARGU{stringA}}\ARGU{true}\ARGU{false}
	\item\verb|\IfEndWith|\etoile{\colorise\ARGU{string}\ARGU{stringA}}\ARGU{true}\ARGU{false}
	\item\verb|\IfInteger|{\colorise\ARGU{number}}\ARGU{true}\ARGU{false}
	\item\verb|\IfDecimal|{\colorise\ARGU{number}}\ARGU{true}\ARGU{false}
	\item\verb|\IfStrEq|\etoile{\colorise\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfEq|\etoile{\colorise\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfStrEqCase|\etoile{\colorise\ARGU{string}\texttt{\color{black}\{}\colorise\ARGU{string1}}\ARGU{code1}\par
		\setbox0=\hbox{{\ttfamily\string\IfStrEqCase}\etoile\ARGU{string}{\ttfamily\{}}
		\hskip\wd0{\colorise\ARGU{string2}}\ARGU{code2}\par
		\hskip\wd0\ \ldots\par
		\hskip\wd0{\colorise\ARGU{string $n$}}\ARGU{code $n$}\verb|}|\arguC{other cases code}
	\item\verb|\IfEqCase|\etoile{\colorise\ARGU{string}\texttt{\color{black}\{}\colorise\ARGU{string1}}\ARGU{code1}\par
		\setbox0=\hbox{{\ttfamily\string\IfEqCase}\etoile\ARGU{string}{\ttfamily\{}}
		\hskip\wd0{\colorise\ARGU{string2}}\ARGU{code2}\par
		\hskip\wd0\ \ldots\par
		\hskip\wd0{\colorise\ARGU{string $n$}}\ARGU{code $n$}\verb|}|\arguC{other cases code}
	\item\verb|\StrBefore|\etoile{\colorise\arguC{number}\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrBehind|\etoile{\colorise\arguC{number}\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrBetween|\etoile{\colorise\arguCC{number1}{number2}\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\arguC{name}
	\item\verb|\StrSubstitute|{\colorise\arguC{number}\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\arguC{name}
	\item\verb|\StrDel|{\colorise\arguC{number}\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrSplit|{\colorise\ARGU{string}\ARGU{number}}\ARGU{stringA}\ARGU{stringB}\qquad{\small(see macro \verb|StrSplit| page~\pageref{StrSplit})}
	\item\verb|\StrGobbleLeft|{\colorise\ARGU{string}\ARGU{number}}\arguC{name}
	\item\verb|\StrLeft|{\colorise\ARGU{string}\ARGU{number}}\arguC{name}
	\item\verb|\StrGobbleRight|{\colorise\ARGU{string}\ARGU{number}}\arguC{name}
	\item\verb|\StrRight|{\colorise\ARGU{string}\ARGU{number}}\arguC{name}
	\item\verb|\StrChar|{\colorise\ARGU{string}\ARGU{number}}\arguC{name}
	\item\verb|\StrMid|{\colorise\ARGU{string}\ARGU{number1}\ARGU{number2}}\arguC{name}
	\item\verb|\StrLen|{\colorise\ARGU{string}}\arguC{name}
	\item\verb|\StrCount|{\colorise\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrPosition|{\colorise\arguC{number}\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrCompare|{\colorise\ARGU{stringA}\ARGU{stringB}}\arguC{name}
\end{itemize}
\parindent0pt

\subsubsection{Chars and tokens allowed in arguments}
First of all, whatever be the current expansion mode, \textbf{tokens with catcode 6 and 14 (usually {\ttfamily\#} and {\ttfamily\%}) are forbidden in all the arguments}\footnote{Maybe, the token {\ttfamily\#} will be allowed in a future version.}.\bigskip

When full expansion mode is activated with \verbinline|\fullexpandarg|, arguments are expanded with an \verbinline|\edef| before they are read by the macro. Consequently, are allowed in arguments:
\parindent3em
\begin{itemize}
	\item letters (uppercase or lowercase, accented\footnote{For a reliable operation with accented letters, the \texttt{\string\fontenc} package with option \texttt{[T1]} and \texttt{\string\inputenc} with appropriated option must be loaded} or not), figures, spaces, and any other character with a catcode of 10, 11 ou 12 (punctuation signs, calculation signs, parenthesis, square bracket, etc).;
	\item tokens with catcode 1 to 4, usually : \verb|{|\quad\verb|}|\footnote{Warning : braces \textbf{must} be balanced in arguments !}\quad\verb|$|\quad\verb|&|
	\item tokens with catcode 7 and 8, usually : \verb|^|\quad\verb|_|
	\item any purely expandable control sequence\footnote{i.e. this control sequence can be {\ttfamily\string\edef}ed.} or tokens with catcode 13 (active chars) whose expansion is allowed chars.
\end{itemize}\parindent0pt
\smallskip

When arguments are not expanded with the use of \verbinline|\noexpandarg|, other tokens can be put in a string whatever be the code they make: any control sequence, even undefined, any token catcode 13. Moreover, test tokens are allowed like \verbinline|\if| or \verbinline|\ifx|, even without their \verbinline|\fi|. On the same way, a \verbinline|\csname| without its \verbinline|\endcsname| is allowed.

In this example, the argument contains a \verbinline|\ifx| \emph{without} the \verbinline|\fi|: the \verbinline|\StrBetween| command extracts and dislpays what is between \verbinline|\ifx| and \verbinline|\else|:\par\medskip\nobreak

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\noexpandarg
\StrBetween{\ifx ab false \else true}{\ifx}{\else}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\noexpandarg
	\StrBetween{\ifx ab false \else true}{\ifx}{\else}
\end{minipage}
\medskip

When \verbinline|\expandarg| is used, the first token needs precaution since it is expanded one time: it must be defined. The other tokens are left unchanged like with \verbinline|\noexpandarg|.

\subsection{Expansion of macros, optional argument}
\label{argumentoptionnel}
The macros of this package are not purely expandable, i.e. they cannot be put in the argument of an \verbinline|\edef|. Nestling macros is not possible neither.\medskip

For this reason, all the macros returning a result (i.e. all excepted the tests) have an optional argument in last position. The syntax is \arguC{name}, where \argu{name} is the name of the control sequence that will receive the result of the macro: the assignment is made with an \verbinline|\edef| which make the result of the macro \argu{name} purely expandable. Of course, if an optional argument is present, the macro does not display anything.\medskip

Thus, this structure not allowed, supposed to assign to \verb|\Result| the 4 chars on the left of \verb|xstring|:\par\nobreak
\hspace{0.2\linewidth}\verbinline|\edef\Result{\StrLeft{xstring}{4}}|\par\nobreak
\qquad is equivalent to :\par\nobreak
\hspace{0.2\linewidth}\verbinline|\StrLeft{xstring}{4}[\Result]|\medskip

And this nested structure, not allowed neither, supposed to remove the first and last char of \verb|xstring|:\par\nobreak
\hspace{0.2\linewidth}\verbinline|\StrGobbleLeft{\StrGobbleRight{xstring}{1}}{1}|\par\nobreak
\qquad should be written like this:\par\nobreak
\hspace{0.2\linewidth}\verbinline|\StrGobbleRight{xstring}{1}[\mystring]|\par\nobreak
\hspace{0.2\linewidth}\verbinline|\StrGobbleleft{\mystring}{1}|\par

\subsection{How does \Xstring read the arguments?}
\label{developpementarguments}
\subsubsection{Syntax unit by \US}
The macros of \Xstring read their arguments \US par \US. In the \TeX{} code, a \US\footnote{For advanced users used to \LaTeX{} programming, a \US is what is gobbled by the macro \texttt{\string\@gobble} whose code is: {\ttfamily\string\def\string\@gobble\string#1\string{\string}}} is either:\parindent3em
\begin{itemize}
	\item a control sequence;
	\item a group, i.e. what is between 2 balanced braces (usually tokens catcode 1 and 2);
	\item a char.
\end{itemize}
\medskip\parindent0pt

Let's see what is a \US with an example. Let's take this argument : "\verb|ab\textbf{xyz}cd|"

It has 6 \USs: "\verb|a|", "\verb|b|", "\verb|\textbf|", "\verb|{xyz}|", "\verb|c|" and "\verb|d|".\medskip

What will happen if, while \verbinline|\noexpandarg| is active, we ask \Xstring to find the length of this argument and find its 4\th "char"\medskip

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\noexpandarg
\StrLen{ab\textbf{xyz}cd}\par
\StrChar{ab\textbf{xyz}cd}{4}[\mychar]
\meaning\mychar
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\noexpandarg
	\StrLen{ab\textbf{xyz}cd}\par
	\StrChar{ab\textbf{xyz}cd}{4}[\mychar]
	\meaning\mychar
\end{minipage}%
\fullexpandarg
\medskip

It is necessary to use \verbinline|\meaning| to see the real expansion of \verb|\mychar|, and not simply call \verb|\mychar| to display it, which make loose informations (braces here). We do not obtain a "char" but a \US, as expected.

\subsubsection{Exploration of groups}
By default, the command \verbinline|\noexploregroups| is called, so in the argument containing the string of tokens, \Xstring does not look into groups, and simply consider them as a \US.

For specific uses, it can be necessary to look into groups: \verbinline|\exploregroups| changes the exploration mode and forces the macros to look inside groups.\medskip

What does this exploration mode in the previous example? \Xstring does not count the group as a single \US but looks inside it and counts the \US found inside (\verb|x|, \verb|y| and \verb|z|), and so on if there were several nested groups:\smallskip

\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\noexpandarg
\exploregroups
\StrLen{ab\textbf{xyz}cd}\par
\StrChar{ab\textbf{xyz}cd}{4}[\mychar]
\meaning\mychar
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\noexpandarg
	\exploregroups
	\StrLen{ab\textbf{xyz}cd}\par
	\StrChar{ab\textbf{xyz}cd}{4}[\mychar]
	\meaning\mychar
\end{minipage}%
\fullexpandarg\noexploregroups
\medskip

Exploring the groups can be usefull for counting a substring in a string (\verbinline|\StrCount|), for the position of a substring in a string (\verbinline|\StrPosition|) or for tests, but has a severe limitation with macros returning a string: when a string is cut inside a group, \textbf{the result does not take into account what is outside this group}. This exploration mode must be used knowingly this limitation when calling macros returning a string.\smallskip

Let's see what this means with an example. We want to know what is on the left of the second appearance of \verb|\a| in the argument \verb|\a1{\b1\a2}\a3|. As groups are explored, this appearance is inside this group : \verb|{\b1\a2}|. The result will be \verb|\b1|. Let's check:\par\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\noexpandarg
\exploregroups
\StrBefore[2]{\a1{\b1\a2}\a3}{\a}[\mycs]
\meaning\mycs
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\noexpandarg
	\exploregroups
	\StrBefore[2]{\a1{\b1\a2}\a3}{\a}[\mycs]
	\meaning\mycs
\end{minipage}%
\medskip

Exploring the groups\footnote{The file test of \Xstring has many examples underlining differences between exploration modes.} can change the behaviour of most of the macros of \Xstring, excepted these macros untouched by the exploration mode; their behaviour is the same in any case: \verbinline|\IfInteger|, \verbinline|\IfDecimal|, \verbinline|\IfStrEq|, \verbinline|\StrEq| et \verbinline|\StrCompare|.

Moreover, 2 macros run in \verbinline|\noexploregroups| mode, whatever be the current mode: \verbinline|\StrBetween| et \verbinline|\StrMid|.\medskip

It is possible to save the exploration mode with \verbinline|\saveexploremode|, then modify it and come back to the situation when it was saved with \verbinline|\restoreexploremode|.

\subsection{Catcode and starred macros}
\label{macrosetoilees}
Macros of this package take the catcodes of tokens into account. To avoid unexpected behaviour (particulary with tests), you should keep in mind that tokens \emph{and their catcodes} are examined.\medskip

For instance, these two arguments:\par\medskip
\hfil\verbinline|{\string a\string b}|\qquad and\qquad\verb|{ab}|\hfil{}\par\smallskip
do \emph{not} expand into equal strings for xstring! Because of the command \verbinline|\string|, the first expands into "\verb|ab|" with catcodes 12 while the second have characters with their natural catcodes 11. Catcodes do not match! It is necessary to be aware of this, particulary with \TeX{} commands like \verbinline|\string| whose expansions are a strings with chars catcodes 12 and 10 : \verbinline|\detokenize|, \verbinline|\meaning|, \verbinline|\jobname|, \verbinline|\fontname|, \verbinline|\romannumeral|, etc.\medskip

Starred macros do not take catcodes into account. They simply convert some arguments into arguments with catcodes 10, 11 and 12, and call the non-starred macros with these modified arguments. The optional arguments are not modified and the catcodes are left unchanged.\medskip

Here is an example:\par\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\IfStrEq{\string a\string b}{ab}{true}{false}\par
\IfStrEq*{\string a\string b}{ab}{true}{false}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\IfStrEq{\string a\string b}{ab}{true}{false}\par
	\IfStrEq*{\string a\string b}{ab}{true}{false}
\end{minipage}%
\smallskip

The strings do not match because of catcode differences: the test is negative in the non-starred macro.\bigskip

\textbf{Warning}: the use of a strarred macro has consequences! The arguments are \guill{detokenized}, thus, there is no more control sequences, groups, neither any special char: everything is converted into chars with "harmless" catcodes.\medskip

For the macros returning a string, if the starred version is used, the result will be a string in which chars have catcodes 12 and 10 for space. For example, after a "\verbinline|\StrBefore*{a \b c d}{c}[\mytext]|", the control sequence \verb|\mytext| expands to "\verb|a|${}_{12}$\verb*| |${}_{10}$\verb|\|${}_{12}$\verb|b|${}_{12}$\verb*| |${}_{10}$".\medskip

The macro with a starred version are listed below. For these macros, if starred version is used, the \textcolor{violet}{purple} arguments will be detokenized:\smallskip

\parindent3em
\begin{itemize}
	\item\verb|\IfSubStr|\etoile\arguC{number}{\colorise\ARGU{string}\ARGU{stringA}}\ARGU{true}\ARGU{false}
	\item\verb|\IfSubStrBefore|\etoile\arguCC{number1}{number2}{\colorise\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfSubStrBehind|\etoile\arguCC{number1}{number2}{\colorise\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfBeginWith|\etoile{\colorise\ARGU{string}\ARGU{stringA}}\ARGU{true}\ARGU{false}
	\item\verb|\IfEndWith|\etoile{\colorise\ARGU{string}\ARGU{stringA}}\ARGU{true}\ARGU{false}
	\item\verb|\IfStrEq|\etoile{\colorise\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfEq|\etoile{\colorise\ARGU{stringA}\ARGU{stringB}}\ARGU{true}\ARGU{false}
	\item\verb|\IfStrEqCase|\etoile{\colorise\ARGU{string}\texttt{\color{black}\{}\colorise\ARGU{string1}}\ARGU{code1}\par
		\setbox0=\hbox{{\ttfamily\string\IfStrEqCase}\etoile\ARGU{string}{\ttfamily\{}}
		\hskip\wd0{\colorise\ARGU{string2}}\ARGU{code2}\par
		\hskip\wd0\ \ldots\par
		\hskip\wd0{\colorise\ARGU{string $n$}}\ARGU{code $n$}\verb|}|\arguC{other cases code}
	\item\verb|\IfEqCase|\etoile{\colorise\ARGU{string}\texttt{\color{black}\{}\colorise\ARGU{string1}}\ARGU{code1}\par
		\setbox0=\hbox{{\ttfamily\string\IfEqCase}\etoile\ARGU{string}{\ttfamily\{}}
		\hskip\wd0{\colorise\ARGU{string2}}\ARGU{code2}\par
		\hskip\wd0\ \ldots\par
		\hskip\wd0{\colorise\ARGU{string $n$}}\ARGU{code $n$}\verb|}|\arguC{other cases code}
	\item\verb|\StrBefore|\etoile\arguC{number}{\colorise\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrBehind|\etoile\arguC{number}{\colorise\ARGU{string}\ARGU{stringA}}\arguC{name}
	\item\verb|\StrBetween|\etoile\arguCC{number1}{number2}{\colorise\ARGU{string}\ARGU{stringA}\ARGU{stringB}}\arguC{name}
	\item\verb|\StrCompare|\etoile{\colorise\ARGU{stringA}\ARGU{stringB}}\arguC{name}
\end{itemize}
\parindent0pt

\section{Advanced macros for programming}
Though \Xstring is able to read arguments containing \TeX{} or \LaTeX{} code, for some advanced programming needs, it can be insufficient. This chapter presents other macros able to get round some limitations.

\subsection{Finding a group, macros {\ttfamily\textbackslash StrFindGroup} and {\ttfamily\textbackslash groupID}}
When \verbinline=\exploregroups= mode is active, the macro \verbinline=\StrFindGroup= finds a group between braces with its identifier:\smallskip

\verbinline|\StrFindGroup|\ARGU{argument}\ARGU{identifier}\arguC{name}\medskip

When the group matching the identifier does not exist, an empty string is assigned to \argu{name}. If the group is found, this group \emph{with its braces} is assigned to \argu{name}.\smallskip

This identifier characterizes the nestling position of the group. It is a list of one or several integers separated with commas. $n_1$, the first integer is the number of the group (not nestled in another) in which the sought group is. Inside this group, the second integer $n_2$ is the number of the group (not nestled in another) in which the sought group is\ldots and so on until the necessary nestling depth is reached to obtain the sougth after group.\bigskip

Let's take an example with 3 levels of nestled groups. In this example, braces delimiting groups are colored in red for nestling level 1, in blue for level 2 and in green for level 3. The groups are numbered with the rule seen above:
\begingroup
	\def\AccO#1{\text{\color{#1}\ttfamily\{}}
	\def\AccF#1{\text{\color{#1}\ttfamily\}}}
	\def\texte#1{\text{\texttt{\color{black}#1}}}
	\def\decalbrace{\vphantom{\underbrace{A}_A}}
	\[\texte{a}{\color{red}\underbrace{\AccO{red}{\color{blue}\underbrace{\decalbrace\AccO{blue}\texte{bc}\AccF{blue}}_{\color{blue}1}}\texte{d}{\color{blue}\underbrace{\decalbrace\AccO{blue}\texte{efg}\AccF{blue}}_{\color{blue}2}}\AccF{red}}_{\color{red}1}}\texte{h}{\color{red}\underbrace{\AccO{red}{\color{blue}\underbrace{\decalbrace\AccO{blue}\texte{ij}\AccF{blue}}_{\color{blue}1}}{\color{blue}\underbrace{\decalbrace\AccO{blue}\texte{k}\AccF{blue}}_{\color{blue}2}}{\color{blue}\underbrace{\AccO{blue}\texte{l}{\color{green}\underbrace{\AccO{green}\texte{m}\AccF{green}}_{\color{green}1}}{\color{green}\underbrace{\AccO{green}\texte{no}\AccF{green}}_{\color{green}2}}\AccF{blue}}_{\color{blue}3}}\texte{p}\AccF{red}}_{\color{red}2}}\]
\endgroup
\smallskip
In this example:\parindent3em
\begin{itemize}
	\item the group \verb={{bc}d{efg}}= has the identifier: \texttt{\color{red}1}
	\item the group \verb={ij}= has the identifier: \texttt{{\color{red}2},\color{blue}1}
	\item the group \verb={no}= has the identifier: \texttt{{\color{red}2},{\color{blue}3},\color{green}2}
	\item the whole argument \verb=a{{bc}d{efg}}h{{ij}{k}{l{m}{no}}p}= has the identifier \verb=0=, only case where the integer 0 is appears in the identifier of a group.
\end{itemize}
\parindent0pt
\medskip
Here is the full example:\par\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\exploregroups
\expandarg
\def\mystring{a{{bc}d{efg}}h{{ij}{k}{l{m}{no}}p}}
\StrFindGroup{\mystring}{1}[\mygroup]
\meaning\mygroup\par
\StrFindGroup{\mystring}{2,1}[\mygroup]
\meaning\mygroup\par
\StrFindGroup{\mystring}{2,3,2}[\mygroup]
\meaning\mygroup\par
\StrFindGroup{\mystring}{2,5}[\mygroup]
\meaning\mygroup\par
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\exploregroups
	\expandarg
	\def\mystring{a{{bc}d{efg}}h{{ij}{k}{l{m}{no}}p}}
	\StrFindGroup{\mystring}{1}[\mygroup]
	\meaning\mygroup\par
	\StrFindGroup{\mystring}{2,1}[\mygroup]
	\meaning\mygroup\par
	\StrFindGroup{\mystring}{2,3,2}[\mygroup]
	\meaning\mygroup\par
	\StrFindGroup{\mystring}{2,5}[\mygroup]
	\meaning\mygroup\par
\end{minipage}%
\bigskip

The reverse process exists, and several macros of \Xstring provide the identifier of the group in which they made a cut or they found a substring. These macros are: \verbinline|\IfSubStr|, \verbinline|\StrBefore|, \verbinline|\StrBehind|, \verbinline|\StrSplit|, \verbinline|\StrLeft|, \verbinline|\StrGobbleLeft|, \verbinline|\StrRight|, \verbinline|\StrGobbleRight|, \verbinline|\StrChar|, \verbinline|\StrPosition|.\medskip

After these macros, the control sequence \verbinline|\groupID| expands to the identifier of the group where the cut has been done or the search has succeeded. When not cut can be done or the search fails, \verbinline|\groupID| is empty. Obvioulsly, the use of \verbinline|\groupID| has sense only when \verbinline|\exploregroups| mode is acive and when non starred macros are used.\smallskip

Here are some examples with the macro \verbinline|\StrChar|:\par\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\exploregroups
char 1 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{1}\qquad
\string\groupID = \groupID\par
char 4 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{4}\qquad
\string\groupID = \groupID\par
char 6 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{6}\qquad
\string\groupID = \groupID\par
char 20 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{20}\qquad
\string\groupID = \groupID
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\exploregroups
	char 1 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{1}\qquad
	\string\groupID = \groupID\par
	char 4 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{4}\qquad
	\string\groupID = \groupID\par
	char 6 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{6}\qquad
	\string\groupID = \groupID\par
	char 20 = \StrChar{a{b{cd}{e{f}g}h}ijkl}{20}\qquad
	\string\groupID = \groupID
\end{minipage}

\subsection{Splitting a string, the macro {\ttfamily\textbackslash StrSplit}}
\label{StrSplit}
Here is the syntax:\smallskip

\verbinline|\StrSplit|\ARGU{string}\ARGU{number}\ARGU{stringA}\ARGU{stringB}
\smallskip

The \argu{string}, is splitted after the \US at position \argu{number}. The left part is assigned to the control sequence \argu{stringA} and the right part is assigned to \argu{stringB}.\par
This macro returns two strings, so it does \emph{not} display anything. Consequently, it does not provide the optional argument in last position.\medskip

\begin{Conditions}
	\item If \argu{number}${}\leqslant0$, \argu{stringA} is empty and \argu{stringB} is equal to \argu{string};
	\item If \argu{number}${}\geqslant$\argu{lengthString}, \argu{stringA} is equal to \argu{string} and \argu{stringB} is empty;
	\item If \argu{string} is empty, \argu{stringA} and \argu{stringB} are empty, whatever be the integer \argu{number}.
\end{Conditions}

\begin{minipage}[c]{0.65\linewidth}

\begin{lstlisting}
\def\redsep{{\color{red}|}}%
\StrSplit{abcdef}{4}{\csA}{\csB}|\csA\redsep\csB|
\StrSplit{a b c }{2}{\csA}{\csB}|\csA\redsep\csB|
\StrSplit{abcdef}{1}{\csA}{\csB}|\csA\redsep\csB|
\StrSplit{abcdef}{5}{\csA}{\csB}|\csA\redsep\csB|
\StrSplit{abcdef}{9}{\csA}{\csB}|\csA\redsep\csB|
\StrSplit{abcdef}{-3}{\csA}{\csB}|\csA\redsep\csB|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\def\redsep{{\color{red}|}}%
	\StrSplit{abcdef}{4}{\csA}{\csB}|\csA\redsep\csB|\par
	\StrSplit{a b c }{2}{\csA}{\csB}|\csA\redsep\csB|\par
	\StrSplit{abcdef}{1}{\csA}{\csB}|\csA\redsep\csB|\par
	\StrSplit{abcdef}{5}{\csA}{\csB}|\csA\redsep\csB|\par
	\StrSplit{abcdef}{9}{\csA}{\csB}|\csA\redsep\csB|\par
	\StrSplit{abcdef}{-3}{\csA}{\csB}|\csA\redsep\csB|
\end{minipage}%

When the exploration of groups is active and the cut is made at the end of a group, the content of the left string will tbe the entire group while the right string will be empty. The example shows this:\par\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\hfill
\begin{lstlisting}
\exploregroups
\StrSplit{ab{cd{ef}gh}ij}{6}\strA\strB
\meaning\strA\par
\meaning\strB
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\exploregroups
	\StrSplit{ab{cd{ef}gh}ij}{6}\strA\strB
	\meaning\strA\par
	\meaning\strB
\end{minipage}%
\medskip

This macro provides a star version: in this case, the cut is made just before the \US which follows the \US at position \argu{number}. Both version give same results, except when the cut is made at the end of a group; in that case, \verbinline|\StrSplit| closes as many group as necessary until it finds the next \US: the cut is made just before this \US.\smallskip

\begin{minipage}[c]{0.65\linewidth}
\hfill
\begin{lstlisting}
\exploregroups
Use without star :\par
\StrSplit{ab{cd{ef}gh}ij}{6}\strA\strB
\meaning\strA\par
\meaning\strB\par
\string\groupID\ = \groupID\par\medskip
Use with star :\par
\StrSplit*{ab{cd{ef}gh}ij}{6}\strA\strB
\meaning\strA\par
\meaning\strB\par
\string\groupID\ = \groupID
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\exploregroups
	Use without star :\par
	\StrSplit{ab{cd{ef}gh}ij}{6}\strA\strB
	\meaning\strA\par
	\meaning\strB\par
	\string\groupID\ = \groupID\par\medskip
	Use with star :\par
	\StrSplit*{ab{cd{ef}gh}ij}{6}\strA\strB
	\meaning\strA\par
	\meaning\strB\par
	\string\groupID\ = \groupID
\end{minipage}%

\subsection{Assign a verb content, the macro \ttfamily\textbackslash verbtocs}
\label{verbtocs}
The macro \verbinline|\verbtocs| allow to read the content of a \guill{verb} argument containing special characters: \verb|&|, \verb|~|, \verb|\|, \verb|{|, \verb|}|, \verb|_|, \verb|#|, \verb|$|, \verb|^| and \verb|%|. The catcodes of \guill{normal} characters are left unchanged while special characters take a catcode 12. Then, these characters are assigned to a control sequence. The syntax is:\par\nobreak\medskip
\hfill\verbinline|\verbtocs|\ARGU{name}|\argu{characters}|\hfill{}
\smallskip

\argu{name} is the name of the control sequence receiving, with an \verbinline|\edef|, the \argu{characters}. \argu{name} thus contains tokens with catcodes 12 (or 10 for space).\medskip

By default, the token delimiting the verb content is \guill{|}. Obviously, this token cannot be both delimiting and being contained into what it delimits. If you need to verbatimize strings containing \guill{|}, you can change at any time the token delimiting the verb content with the macro:\par\nobreak\medskip
\hfill\verbinline|\setverbdelim|\ARGU{character}\hfill{}\smallskip

Any \argu{token} can be used\footnote{Several tokens can be used, but the syntax of \texttt{\textbackslash verbtocs} becomes less readable ! For this reason, a warning occurs when the argument of \texttt{\textbackslash setverbdelim} contains more than a single token.}. For example, after \verbinline|\setverbdelim{=}|, a verb argument look like this: \verb|=|\argu{characters}\verb|=|.\medskip

About verb arguments, keep in mind that:
\begin{itemize}
	\item all the characters before |\argu{characters}| are ignored;
	\item inside the verb argument, all the spaces are taken into account, even if they are consecutive.
\end{itemize}
\medskip

Example:\par\nobreak\medskip
\begin{minipage}[c]{0.65\linewidth}
\lstset{deletecomment=[l]\%}
\begin{lstlisting}
\verbtocs{\result}  |a   & b{ c% d$ e \f|
I display the result :\par\result
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\verbtocs{\result}  |a   & b{ c% d$ e \f|
	I display the result :\par\result
\end{minipage}%

\subsection{Tokenization of a text to a control sequence, the macro \ttfamily\textbackslash tokenize}
The reverse process of what has been seen above is to transform chars into tokens. This is done by the macro:\par\nobreak\medskip
\hfill\verbinline|\tokenize|\ARGU{name}\ARGU{control sequences}\hfill{}
\smallskip

\argu{control sequences} is fully expanded if \verbinline|\fullexpandarg| has been called, and is not expanded if \verbinline|\noexpandarg| or \verbinline|\expandarg| are active. After expansion, the chars are tokenized to tokens and assigned to \argu{name} with a \verbinline|\def|.\medskip

Example:\par\nobreak\medskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\verbtocs{\text}|\textbf{a} $\frac{1}{2}$|
text : \text
\tokenize{\result}{\text}\par
result : \result
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\verbtocs{\text}
	  |\textbf{a} $\frac{1}{2}$|
	text : \text
	\tokenize{\result}{\text}	\par
	result : \result
\end{minipage}%
\medskip

Obviously, the control sequence \verb|\result| can be called at the last line since the control sequences it contains are defined.

\subsection{Expansion of a control sequence before verbatimize, the macros {\ttfamily\textbackslash StrExpand} and {\ttfamily\textbackslash scancs}}
\label{scancs}
The macro \verbinline|\StrExpand| expands the tokens of a string:\par\nobreak\medskip
\verbinline|\StrExpand|\arguC{number}\ARGU{string}\ARGU{name}\smallskip

By default, \argu{number} is 1 and represnts the number of times each token of \argu{string} has to be expanded. The \argu{name} is a control sequence receiving the result of the expansions.\medskip

Macro works sequentially and by pass: in a pass, each token from left to right is replaced by its 1-expansion. After this expansion, if the \argu{number} of expansions is not reached, an other pass starts, and so on.\medskip

Here is an example:\par\nobreak\smallskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\def\csA{1 2}
\def\csB{a \csA}
\def\csC{\csB\space}
\def\csD{x{\csA y}\csB{\csC z}}
Expansion of \string\csD\ at\par
\StrExpand[0]{\csD}{\csE} depth 0 :
\detokenize\expandafter{\csE}\par
\StrExpand[1]{\csD}{\csE} depth 1 :
\detokenize\expandafter{\csE}\par
\StrExpand[2]{\csD}{\csE} depth 2 :
\detokenize\expandafter{\csE}\par
\StrExpand[3]{\csD}{\csE} depth 3 :
\detokenize\expandafter{\csE}\par
\StrExpand[4]{\csD}{\csE} depth 4 :
\detokenize\expandafter{\csE}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\def\csA{1 2}
	\def\csB{a \csA}
	\def\csC{\csB\space}
	\def\csD{x{\csA y}\csB{\csC z}}
	Expansion of \string\csD\ at\par
	\StrExpand[0]{\csD}{\csE} depth 0 :
	\detokenize\expandafter{\csE}\par
	\StrExpand[1]{\csD}{\csE} depth 1 :
	\detokenize\expandafter{\csE}\par
	\StrExpand[2]{\csD}{\csE} depth 2 :
	\detokenize\expandafter{\csE}\par
	\StrExpand[3]{\csD}{\csE} depth 3 :
	\detokenize\expandafter{\csE}\par
	\StrExpand[4]{\csD}{\csE} depth 4 :
	\detokenize\expandafter{\csE}
\end{minipage}%
\medskip

The macro expands each token consecutively, and does not see what follows: tokens whose expansion depends on other tokens cannot be expanded with this macro. For instance, though "\hbox{\verbinline|\iftrue A\else B\fi|}" has a natural expansion ("A"), it cannot be put in the argument of \verbinline|\StrExpand| and:\par\nobreak\smallskip
\hfil\verbinline|\StrExpand{\iftrue A\else B\fi}\resultat|\hfil{}\par\nobreak\smallskip
provokes an error because the first token "\verbinline|\iftrue|" is expanded \emph{alone} without seeing its \verbinline-\fi- which makes \TeX{} angry.

Expansion inside groups is \emph{independant} of the exploration mode: this macro has its own command to expand or not what is inside the groups. By default, tokens inside groups are expanded, but this can be changed with the macro \verbinline-\noexpandingroups-. The default behaviour can be recoverd with \verbinline-\expandingroups-.\bigskip

The \verbinline-\scancs- macro returns the detokenized result:\par\nobreak\medskip
\verbinline|\scancs|\arguC{number}\ARGU{name}\ARGU{string}\par\nobreak\smallskip
The \argu{number} is 1 by default and represents the number of expansions.\smallskip

\verbinline-\scancs-  has been kept for compatibility with older versions of \Xstring. This macro now unnecessry, simply takes the result of \verbinline|\StrExpand| and \verbinline|\detokenize| it.

\subsection{Inside the definition of a macro}
Some difficulties arise inside the definition of a macro, i.e. between braces following a \verbinline|\def\macro| or a\\\verbinline|\newcommand\macro|.\medskip

It is forbidden to use the command \verbinline|\verb| inside the definition of a macro. For the same reasons:\par\medskip
\hfill\textbf{Do not use \texttt{\textbackslash verbtocs} inside the definition of a macro}.\hfill{}\medskip

But then, how to manipulate special characters and "verbatimize" inside the définition of macros ?\bigskip

The \verbinline|\detokenize| primitive of $\varepsilon$-\TeX can be used but it has limitations:
\begin{itemize}
	\item braces must be balanced;
	\item consecutive spaces make a single space;
	\item the \verb|%| sign is not allowed;
	\item a space is inserted after each control sequence;
	\item \verb|#| signs become  \verb|##|.
\end{itemize}
\medskip

It is better to use \verbinline|\scancs| and define \emph{outside the definition of the macros} control sequences containing special characters with \verbinline|\verbtocs|. It is also possible to use \verbinline|\tokenize| to transform the final result (which is generaly \texte{10,11,12}) into control sequences. See example using these macros at the end of this manual, page~\pageref{exemples}.\medskip

In the following teaching example\footnote{It is possible to make much more simple using \texttt{\textbackslash detokenize}. The macro becomes:\par\texttt{\textbackslash newcommand\textbackslash bracearg[1]\{\textbackslash detokenize\{\{\#1\}\}\}}}, the macro \verb|\bracearg| adds braces to its argument. To make this possible, 2 control sequences \verb|\Ob| and \verb|\Cb| containing "\verb|{|" and "\verb|}|" are defined outside the definition of \verb|\bracearg|, and expanded inside it:\par\nobreak\medskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\verbtocs{\Ob}|{|
\verbtocs{\Cb}|}|
\newcommand\bracearg[1]{%
	\def\text{#1}%
	\scancs{\result}{\Ob\text\Cb}%
	\result}

\bracearg{xstring}\par
\bracearg{\a}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\verbtocs{\Ob}|{|
	\verbtocs{\Cb}|}|
	\newcommand\bracearg[1]{%
		\def\text{#1}%
		\scancs{\result}{\Ob\text\Cb}%
		\result}

	\bracearg{xstring}\par
	\bracearg{\a}
\end{minipage}%

\subsection{The macro \ttfamily\textbackslash StrRemoveBraces}
Advanced users may need to remove the braces of an argument.

The macro \verbinline|\StrRemoveBraces| does this. Its syntax is:\smallskip

\verbinline|\StrRemoveBraces|\ARGU{string}\arguC{name}
\smallskip

This macro is sensitive to exploration mode and will remove \emph{all} the braces with \verbinline|\exploregroups| while it will remove braces of lower level with \verbinline|\noexploregroups|.\medskip

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\noexploregroups
\StrRemoveBraces{a{b{c}d}e{f}g}[\mycs]
\meaning\mycs

\exploregroups
\StrRemoveBraces{a{b{c}d}e{f}g}[\mycs]
\meaning\mycs
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\noexploregroups
	\StrRemoveBraces{a{b{c}d}e{f}g}[\mycs]
	\meaning\mycs

	\exploregroups
	\StrRemoveBraces{a{b{c}d}e{f}g}[\mycs]
	\meaning\mycs
\end{minipage}%

\subsection{Examples}
\label{exemples}
Here are some very simple examples involving the macros of this package in programming purposes.

\subsubsection{Example 1}
We want to substitute the 2 first \verbinline|\textit| by \verbinline|\textbf| in the control sequence \verb|\myCS| which contains \par\smallskip
\hfill\verbinline|\textit{A}\textit{B}\textit{C}|\hfill{}
\medskip

We expect: \textbf{A}\textbf{B}\textit{C}\medskip

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\expandarg
\def\myCS{\textit{A}\textit{B}\textit{C}}
\def\pattern{\textit}
\def\replace{\textbf}
\StrSubstitute[2]{\myCS}{\pattern}{\replace}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\expandarg
	\def\myCS{\textit{A}\textit{B}\textit{C}}
	\def\pattern{\textit}
	\def\replace{\textbf}
	\StrSubstitute[2]{\myCS}{\pattern}{\replace}
\end{minipage}%
\medskip

It is possible to avoid to define \verb|\pattern| and \verb|\replace|: a "snare" can be used. It can be a control sequence which expansion is empty, like the famous \verbinline|\empty|. The code would have been:\par\nobreak\smallskip
\hfil\verbinline|\StrSubstitute[2]{\myCS}{\empty\textit}{\empty\textbf}|\hfil{}\medskip

With this code, in both arguments, the first token \verbinline|\empty| is expanded to "nothing" and the following significant tokens \verbinline|\textit| and \verbinline|textbf| are left unchanged.\smallskip

By this way, \verbinline|\empty| is a way to "hack" \verbinline|\expandarg|: it allows to avoid the expansion of all the other tokens. The control sequence \verbinline|\noexpand| can be used instead of \verbinline|\empty| for the same result.

\subsubsection{Exemple 2}
Here, we try to write a macro which gobbles \verb|n| \USs in a string from a given position, and assigns the result to a control sequence.

Let's call this macro \verb|StringDel| and let's give it this syntax:\par\nobreak
\hfil\verb|\StringDel{string}{position}{n}{\name_of_result}|\hfil{}
\medskip

We can proceed like this: take the string before the position and save it. Then remove \verb|n + position| \USs from the initial string, and add (concatenate) this result to the string previously saved. This gives the following code:\par\nobreak\medskip

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\newcommand\StringDel[4]{%
	\begingroup
	\expandarg% locally in this group
	\StrLeft{\empty#1}{\number\numexpr#2-1}[#4]%
	\StrGobbleLeft{\empty#1}{\numexpr#2+#3-1}[\StrA]%
	\expandafter\expandafter\expandafter\endgroup
	\expandafter\expandafter\expandafter\def
	\expandafter\expandafter\expandafter#4%
	\expandafter\expandafter\expandafter
	{\expandafter#4\StrA}%
}

\noexploregroups
\StringDel{abcdefgh}{2}{3}{\cmd}
\meaning\cmd

\StringDel{a\textbf{1}b\textbf{2c}3d}{3}{4}{\cmd}
\meaning\cmd
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\newcommand\StringDel[4]{%
		\begingroup
		\expandarg% locally in this group
		\StrLeft{\empty#1}{\number\numexpr#2-1}[#4]%
		\StrGobbleLeft{\empty#1}{\numexpr#2+#3-1}[\StrA]%
		\expandafter\expandafter\expandafter\endgroup
		\expandafter\expandafter\expandafter\def
		\expandafter\expandafter\expandafter#4%
		\expandafter\expandafter\expandafter{\expandafter#4\StrA}%
	}

	\noexploregroups
	\StringDel{abcdefgh}{2}{3}{\cmd}
	\meaning\cmd

	\StringDel{a\textbf{1}b\textbf{2c}3d}{3}{4}{\cmd}
	\meaning\cmd
\end{minipage}%
\fullexpandarg\bigskip

To concatenate, the \LaTeX{} macro \verb|\g@addto@macro| could have been used, leading to a lighter code without the huge bridge of \verbinline|\expandafter|. The assignment\footnote{The macro {\ttfamily\string\g@addto@macro} can be used if the catcode of "{\ttfamily\string@}" is temporarily changed with {\ttfamily\string\makeatletter} and restored with {\ttfamily\string\makeatother}} can be written like this:\par\nobreak\smallskip
\hfil\verbinline|\expandafter\g@addto@macro\expandafter#4\expandafter{\StrA}\endgroup|\hfil{}

\subsubsection{Example 3}
Let's try to write a macro \verb|\tofrac| that transforms an argument of this type \guill{a/b} into \guill{$\frac{a}{b}$}.\par\medskip

First of all, let's cancel the expansion of arguments with \verbinline|\noexpandarg|, we do not need expansion here. Then, it's easy to cut what is before and behind the first occurrence of \guill{/} (assumed there is a single occurrence) and assign it to \verb|\num| and \verb|\den| and simply call the macro \verbinline|\frac| :\par\nobreak\medskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\noexpandarg
\newcommand\tofrac[1]{%
	\StrBefore{#1}{/}[\num]%
	\StrBehind{#1}{/}[\den]%
	$\frac{\num}{\den}$%
}
\tofrac{15/9}
\tofrac{u_{n+1}/u_n}
\tofrac{a^m/a^n}
\tofrac{x+\sqrt{x}/\sqrt{x^2+x+1}}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\noexpandarg
	\newcommand\tofrac[1]{%
		\StrBefore{#1}{/}[\num]%
		\StrBehind{#1}{/}[\den]%
		$\frac{\num}{\den}$%
	}
	\tofrac{15/9}
	\tofrac{u_{n+1}/u_n}
	\tofrac{a^m/a^n}
	\tofrac{x+\sqrt{x}/\sqrt{x^2+x+1}}
\end{minipage}%

\subsubsection{Example 4}
Let's try to write a macro \verb|\boldafter| which writes in bold the first word that follows the word contained in the expansion of \verb|\word|.\medskip

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\newcommand\boldafter[2]{%
	\noexpandarg
	\StrBehind[1]{#1 }{ #2 }[\word]%
	\expandarg
	\StrBefore{\word}{ }[\word]%
	\StrSubstitute[1]{#1}{\word}{\textbf{\word}}%
}

\boldafter{The xstring package is new}{xstring}

\boldafter{The xstring package is new}{ring}

\boldafter{The xstring package is new}{is}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\newcommand\boldafter[2]{%
		\noexpandarg
		\StrBehind[1]{#1 }{ #2 }[\word]%
		\expandarg
		\StrBefore{\word}{ }[\word]%
		\StrSubstitute[1]{#1}{\word}{\textbf{\word}}%
	}

	\boldafter{The xstring package is new}{xstring}

	\boldafter{The xstring package is new}{ring}

	\boldafter{The xstring package is new}{is}
\end{minipage}%
\fullexpandarg

\subsubsection{Example 5}
How to reverse the order of the 2 first control sequences? For this, a macro \verb|\swaptwofirst| does the job and displays the result. But this time, it is not possible to seek the token \verb|\| (catcode 0) with the macros of \Xstring. This is why the use of \verbinline|\scancs| is necessary: after the detokenization of the argument, it becomes possible to search the char \verb|\| (catcode 12). At line 5, a retokenization is done by \verbinline|\tokenize| and \verb|\before| and \verb|\after| are swapped at this moment.\medskip

\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\verbtocs{\antislash}|\|
\newcommand\swaptwofirst[1]{%
	\begingroup
	\fullexpandarg
	\scancs[0]\mystring{#1}%
	\StrBefore[3]{\mystring}{\antislash}[\firsttwo]%
	\StrBehind{\mystring}{\firsttwo}[\others]
	\StrBefore[2]{\firsttwo}{\antislash}[\before]
	\StrBehind{\firsttwo}{\before}[\after]%
	\tokenize\myCS{\after\before\others}%
	\myCS
	\endgroup
}

\swaptwofirst{\underline{A}\textbf{B}\textit{C}}

\swaptwofirst{\Large\underline{A}\textbf{B}123}
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\verbtocs{\antislash}|\|
	\newcommand\swaptwofirst[1]{%
		\begingroup
		\fullexpandarg
		\scancs[0]\mystring{#1}%
		\StrBefore[3]{\mystring}{\antislash}[\firsttwo]%
		\StrBehind{\mystring}{\firsttwo}[\others]
		\StrBefore[2]{\firsttwo}{\antislash}[\before]
		\StrBehind{\firsttwo}{\before}[\after]%
		\tokenize\myCS{\after\before\others}%
		\myCS
		\endgroup
	}

	\swaptwofirst{\underline{A}\textbf{B}\textit{C}}

	\swaptwofirst{\Large\underline{A}\textbf{B}123}
\end{minipage}%


\subsubsection{Example 6}
In a string, we want to find the $n$\th{} word between 2 given delimiters. For this, let's write a macro \verb|\findword| with an optional argument which content is the delimiter (space by default), 1 argument containing the string and an other argument containing the number $n$.\medskip

The macro \verb|\findword| artfully uses \verbinline|\StrBetween| and \verbinline|\numexpr|:\par\nobreak\medskip
\begin{minipage}[c]{0.65\linewidth}
\begin{lstlisting}
\newcommand\findword[3][ ]{%
	\StrBetween[#3,\numexpr#3+1]{#1#2#1}{#1}{#1}%
}
\noexpandarg
|\findword{a bc d\textbf{e f} gh}{3}|

|\findword[\nil]{1 \nil 2 3 \nil4\nil5}{2}|
\end{lstlisting}%
\end{minipage}\hfill
\begin{minipage}[c]{0.35\linewidth}
	\styleexercice
	\newcommand\findword[3][ ]{%
		\StrBetween[#3,\numexpr#3+1]{#1#2#1}{#1}{#1}%
	}
	\noexpandarg
	|\findword{a bc d\textbf{e f} gh}{3}|

	|\findword[\nil]{1 \nil 2 3 \nil4\nil5}{2}|
\end{minipage}%

\bigskip\bigskip
\begin{center}
$\star$\par
$\star$\quad$\star$
\end{center}
\par\nobreak\bigskip\bigskip
That's all, I hope you will find this package useful!\par\nobreak
Please, send me an \href{mailto:unbonpetit@netc.fr}{email} if you find a bug or if you have any idea of improvement\ldots\par\nobreak\medskip
Christian Tellechea
\end{document}