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1 % \iffalse meta-comment
2 %
3 % Copyright 1993-2016
4 % The LaTeX3 Project and any individual authors listed elsewhere
5 % in this file.
6 %
7 % This file is part of the LaTeX base system.
8 % -------------------------------------------
9 %
10 % It may be distributed and/or modified under the
11 % conditions of the LaTeX Project Public License, either version 1.3c
12 % of this license or (at your option) any later version.
13 % The latest version of this license is in
14 % http://www.latex-project.org/lppl.txt
15 % and version 1.3c or later is part of all distributions of LaTeX
16 % version 2005/12/01 or later.
17 %
18 % This file has the LPPL maintenance status "maintained".
19 %
20 % The list of all files belonging to the LaTeX base distribution is
21 % given in the file `manifest.txt'. See also `legal.txt' for additional
22 % information.
23 %
24 % The list of derived (unpacked) files belonging to the distribution
25 % and covered by LPPL is defined by the unpacking scripts (with
26 % extension .ins) which are part of the distribution.
27 %
28 % \fi
29 %
30 % \iffalse
31 %%% From File: ltcntrl.dtx
32 %<*driver>
33 % \fi
34 \ProvidesFile{ltcntrl.dtx}
35 [2014/04/21 v1.0h LaTeX Kernel (program control)]
36 % \iffalse
37 \documentclass{ltxdoc}
38 \GetFileInfo{ltcntrl.dtx}
39 \title{\filename}
40 \date{\filedate}
41 \author{%
42 Johannes Braams\and
43 David Carlisle\and
44 Alan Jeffrey\and
45 Leslie Lamport\and
46 Frank Mittelbach\and
47 Chris Rowley\and
48 Rainer Sch\"opf}
49 \begin{document}
50 \MaintainedByLaTeXTeam{latex}
51 \maketitle
52 \DocInput{\filename}
53 \end{document}
54 %</driver>
55 % \fi
56 %
57 %
58 % \changes{v1.0a}{1994/05/16}{(ASAJ) Split from ltinit.dtx.}
59 % \changes{v1.0b}{1994/11/17}
60 % {\cs{@tempa} to \cs{reserved@a}}
61 % \changes{v1.0c}{1994/11/28}
62 % {Documentation improvements}
63 %
64 % \section{Program control structure}
65 %
66 % This section defines a number of control structure macros, such as
67 % while-loops and for-loops.
68 %
69 % \StopEventually{}
70 %
71 % \begin{oldcomments}
72 % \begin{macrocode}
73 %<*2ekernel>
74 \message{control,}
75 % \end{macrocode}
76 %
77 % \@whilenum TEST \do {BODY}
78 % \@whiledim TEST \do {BODY} : These implement the loop
79 % while TEST do BODY od
80 % where TEST is a TeX \ifnum or \ifdim test, respectively.
81 % They are optimized for the normal case of TEST initially false.
82 %
83 % \@whilesw SWITCH \fi {BODY} : Implements the loop
84 % while SWITCH do BODY od
85 % Optimized for normal case of SWITCH initially false.
86 %
87 % \@for NAME := LIST \do {BODY} : Assumes that LIST expands to A1,A2,
88 % ... ,An .
89 % Executes BODY n times, with NAME = Ai on the i-th iteration.
90 % Optimized for the normal case of n = 1. Works for n=0.
91 %
92 % \@tfor NAME := LIST \do {BODY}
93 % if, before expansion, LIST = T1 ... Tn where each Ti is a
94 % token or {...}, then executes BODY n times, with NAME = Ti
95 % on the i-th iteration. Works for n=0.
96 %
97 % NOTES: 1. These macros use no \@temp sequences.
98 % 2. These macros do not work if the body contains anything that
99 % looks syntactically to TeX like an improperly balanced \if
100 % \else \fi.
101 %
102 % \@whilenum TEST \do {BODY} ==
103 % BEGIN
104 % if TEST
105 % then BODY
106 % \@iwhilenum{TEST \relax BODY}
107 % END
108 %
109 % \@iwhilenum {TEST BODY} ==
110 % BEGIN
111 % if TEST
112 % then BODY
113 % \@nextwhile = def(\@iwhilenum)
114 % else \@nextwhile = def(\@whilenoop)
115 % fi
116 % \@nextwhile {TEST BODY}
117 % END
118 %
119 % \@whilesw SWITCH \fi {BODY} ==
120 % BEGIN
121 % if SWITCH
122 % then BODY
123 % \@iwhilesw {SWITCH BODY}\fi
124 % fi
125 % END
126 %
127 % \@iwhilesw {SWITCH BODY} \fi ==
128 % BEGIN
129 % if SWITCH
130 % then BODY
131 % \@nextwhile = def(\@iwhilesw)
132 % else \@nextwhile = def(\@whileswnoop)
133 % fi
134 % \@nextwhile {SWITCH BODY} \fi
135 % END
136 %
137 % \end{oldcomments}
138 %
139 % \begin{macro}{\@whilenoop}
140 % \begin{macro}{\@whilenum}
141 % \begin{macro}{\@iwhilenum}
142 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
143 % \changes{v1.0g}{1995/08/16}{Removed \cs{@whilenoop}}
144 % \changes{v1.0g}{1995/08/16}{Made defs long}
145 % \begin{macrocode}
146 \long\def\@whilenum#1\do #2{\ifnum #1\relax #2\relax\@iwhilenum{#1\relax
147 #2\relax}\fi}
148 \long\def\@iwhilenum#1{\ifnum #1\expandafter\@iwhilenum
149 \else\expandafter\@gobble\fi{#1}}
150 % \end{macrocode}
151 % \end{macro}
152 % \end{macro}
153 % \end{macro}
154 %
155 % \begin{macro}{\@whiledim}
156 % \begin{macro}{\@iwhiledim}
157 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
158 % \changes{v1.0g}{1995/08/16}{Removed \cs{@whilenoop}}
159 % \changes{v1.0g}{1995/08/16}{Made defs long}
160 % \begin{macrocode}
161 \long\def\@whiledim#1\do #2{\ifdim #1\relax#2\@iwhiledim{#1\relax#2}\fi}
162 \long\def\@iwhiledim#1{\ifdim #1\expandafter\@iwhiledim
163 \else\expandafter\@gobble\fi{#1}}
164 % \end{macrocode}
165 % \end{macro}
166 % \end{macro}
167 %
168 % \begin{macro}{\@whileswnoop}
169 % \begin{macro}{\@whilesw}
170 % \begin{macro}{\@iwhilesw}
171 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
172 % \changes{v1.0g}{1995/08/16}{Removed \cs{@whileswnoop}}
173 % \begin{macrocode}
174 \long\def\@whilesw#1\fi#2{#1#2\@iwhilesw{#1#2}\fi\fi}
175 \long\def\@iwhilesw#1\fi{#1\expandafter\@iwhilesw
176 \else\@gobbletwo\fi{#1}\fi}
177 % \end{macrocode}
178 % \end{macro}
179 % \end{macro}
180 % \end{macro}
181 %
182 % \begin{oldcomments}
183 %
184 % \@for NAME := LIST \do {BODY} ==
185 % BEGIN \@forloop expand(LIST),\@nil,\@nil \@@ NAME {BODY} END
186 %
187 % \@forloop CAR, CARCDR, CDRCDR \@@ NAME {BODY} ==
188 % BEGIN
189 % NAME = CAR
190 % if def(NAME) = def(\@nnil)
191 % else BODY;
192 % NAME = CARCDR
193 % if def(NAME) = def(\@nnil)
194 % else BODY
195 % \@iforloop CDRCDR \@@ NAME \do {BODY}
196 % fi
197 % fi
198 % END
199 %
200 % \@iforloop CAR, CDR \@@ NAME {BODY} =
201 % NAME = CAR
202 % if def(NAME) = def(\@nnil)
203 % then \@nextwhile = def(\@fornoop)
204 % else BODY ;
205 % \@nextwhile = def(\@iforloop)
206 % fi
207 % \@nextwhile name cdr {body}
208 %
209 % \@tfor NAME := LIST \do {BODY}
210 % = \@tforloop LIST \@nil \@@ NAME {BODY}
211 %
212 % \@tforloop car cdr \@@ name {body} =
213 % name = car
214 % if def(name) = def(\@nnil)
215 % then \@nextwhile == \@fornoop
216 % else body ;
217 % \@nextwhile == \@forloop
218 % fi
219 % \@nextwhile name cdr {body}
220 % \end{oldcomments}
221 %
222 % \begin{macro}{\@nnil}
223 % \begin{macrocode}
224 \def\@nnil{\@nil}
225 % \end{macrocode}
226 % \end{macro}
227 %
228 % \begin{macro}{\@empty}
229 % \begin{macrocode}
230 \def\@empty{}
231 % \end{macrocode}
232 % \end{macro}
233 %
234 % \begin{macro}{\@fornoop}
235 % \changes{v1.0g}{1995/08/16}{Made defs long}
236 % \changes{v1.0h}{2007/08/06}{Really make defs long}
237 % \begin{macrocode}
238 \long\def\@fornoop#1\@@#2#3{}
239 % \end{macrocode}
240 % \end{macro}
241 %
242 % \begin{macro}{\@for}
243 % \changes{v1.0d}{1995/04/24}
244 % {Dont expand second argument with \cs{edef}: /1317 (DPC)}
245 % \begin{macrocode}
246 \long\def\@for#1:=#2\do#3{%
247 \expandafter\def\expandafter\@fortmp\expandafter{#2}%
248 \ifx\@fortmp\@empty \else
249 \expandafter\@forloop#2,\@nil,\@nil\@@#1{#3}\fi}
250 % \end{macrocode}
251 % \end{macro}
252 %
253 % \begin{macro}{\@forloop}
254 % \changes{v1.0g}{1995/08/16}{Made defs long}
255 % \begin{macrocode}
256 \long\def\@forloop#1,#2,#3\@@#4#5{\def#4{#1}\ifx #4\@nnil \else
257 #5\def#4{#2}\ifx #4\@nnil \else#5\@iforloop #3\@@#4{#5}\fi\fi}
258 % \end{macrocode}
259 % \end{macro}
260 %
261 % \begin{macro}{\@iforloop}
262 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
263 % \changes{v1.0g}{1995/08/16}{Made defs long}
264 % \begin{macrocode}
265 \long\def\@iforloop#1,#2\@@#3#4{\def#3{#1}\ifx #3\@nnil
266 \expandafter\@fornoop \else
267 #4\relax\expandafter\@iforloop\fi#2\@@#3{#4}}
268 % \end{macrocode}
269 % \end{macro}
270 %
271 % \begin{macro}{\@tfor}
272 % \changes{LaTeX209}{1991/10/17}
273 % {(Rms) \cs{xdef} replaced by \cs{def}
274 % (See FMi's array.doc)}
275 % \changes{v1.0c}{1994/03/13}
276 % {(DPC) Add \cs{@tf@r} so a single group is
277 % correctly treated.}
278 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
279 % \changes{v1.0g}{1995/08/16}{Made defs long}
280 % \begin{macrocode}
281 \def\@tfor#1:={\@tf@r#1 }
282 \long\def\@tf@r#1#2\do#3{\def\@fortmp{#2}\ifx\@fortmp\space\else
283 \@tforloop#2\@nil\@nil\@@#1{#3}\fi}
284 \long\def\@tforloop#1#2\@@#3#4{\def#3{#1}\ifx #3\@nnil
285 \expandafter\@fornoop \else
286 #4\relax\expandafter\@tforloop\fi#2\@@#3{#4}}
287 % \end{macrocode}
288 % \end{macro}
289 %
290 % \begin{macro}{\@break@tfor}
291 % Break out of a |\@tfor| loop. This should be called \emph{inside}
292 % the scope of an |\if|. See |\@iffileonpath| for an example.
293 % \changes{v1.0l}{1994/05/02}{Macro added (from ltfiles.dtx)}
294 % \changes{v1.0g}{1995/08/16}{Made long}
295 % \begin{macrocode}
296 \long\def\@break@tfor#1\@@#2#3{\fi\fi}
297 % \end{macrocode}
298 % \end{macro}
299 %
300 % \begin{macro}{\@removeelement}
301 % Removes an element from a comma-separated list and puts it into
302 % a control sequence, called as
303 % |\@removeelement{|\meta{element}|}{|\meta{list}|}{|\meta{cs}|}|.
304 % Due to the implementation method the \meta{element} is not allowed
305 % to contain braces.
306 % \begin{macrocode}
307 \def\@removeelement#1#2#3{%
308 \def\reserved@a##1,#1,##2\reserved@a{##1,##2\reserved@b}%
309 \def\reserved@b##1,\reserved@b##2\reserved@b{%
310 \ifx,##1\@empty\else##1\fi}%
311 \edef#3{%
312 \expandafter\reserved@b\reserved@a,#2,\reserved@b,#1,\reserved@a}}
313 % \end{macrocode}
314 % \end{macro}
315 %
316 %
317 % \changes{v1.0e}{1995/04/29}{Removed unused defs for
318 % \cs{@setprotect} and \cs{@resetprotect}}
319 % \changes{v1.0e}{1995/04/29}{Moved init of \cs{protect}
320 % to ltdefns.dtx}
321 % \begin{macrocode}
322 %</2ekernel>
323 % \end{macrocode}
324 %
325 %\Finale
326 \endinput