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1 % \iffalse meta-comment
2 %
3 % Copyright 1993-2015
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 % \CheckSum{176}
58 %
59 % \changes{v1.0a}{1994/05/16}{(ASAJ) Split from ltinit.dtx.}
60 % \changes{v1.0b}{1994/11/17}
61 % {\cs{@tempa} to \cs{reserved@a}}
62 % \changes{v1.0c}{1994/11/28}
63 % {Documentation improvements}
64 %
65 % \section{Program control structure}
66 %
67 % This section defines a number of control structure macros, such as
68 % while-loops and for-loops.
69 %
70 % \StopEventually{}
71 %
72 % \begin{oldcomments}
73 % \begin{macrocode}
74 %<*2ekernel>
75 \message{control,}
76 % \end{macrocode}
77 %
78 % \@whilenum TEST \do {BODY}
79 % \@whiledim TEST \do {BODY} : These implement the loop
80 % while TEST do BODY od
81 % where TEST is a TeX \ifnum or \ifdim test, respectively.
82 % They are optimized for the normal case of TEST initially false.
83 %
84 % \@whilesw SWITCH \fi {BODY} : Implements the loop
85 % while SWITCH do BODY od
86 % Optimized for normal case of SWITCH initially false.
87 %
88 % \@for NAME := LIST \do {BODY} : Assumes that LIST expands to A1,A2,
89 % ... ,An .
90 % Executes BODY n times, with NAME = Ai on the i-th iteration.
91 % Optimized for the normal case of n = 1. Works for n=0.
92 %
93 % \@tfor NAME := LIST \do {BODY}
94 % if, before expansion, LIST = T1 ... Tn where each Ti is a
95 % token or {...}, then executes BODY n times, with NAME = Ti
96 % on the i-th iteration. Works for n=0.
97 %
98 % NOTES: 1. These macros use no \@temp sequences.
99 % 2. These macros do not work if the body contains anything that
100 % looks syntactically to TeX like an improperly balanced \if
101 % \else \fi.
102 %
103 % \@whilenum TEST \do {BODY} ==
104 % BEGIN
105 % if TEST
106 % then BODY
107 % \@iwhilenum{TEST \relax BODY}
108 % END
109 %
110 % \@iwhilenum {TEST BODY} ==
111 % BEGIN
112 % if TEST
113 % then BODY
114 % \@nextwhile = def(\@iwhilenum)
115 % else \@nextwhile = def(\@whilenoop)
116 % fi
117 % \@nextwhile {TEST BODY}
118 % END
119 %
120 % \@whilesw SWITCH \fi {BODY} ==
121 % BEGIN
122 % if SWITCH
123 % then BODY
124 % \@iwhilesw {SWITCH BODY}\fi
125 % fi
126 % END
127 %
128 % \@iwhilesw {SWITCH BODY} \fi ==
129 % BEGIN
130 % if SWITCH
131 % then BODY
132 % \@nextwhile = def(\@iwhilesw)
133 % else \@nextwhile = def(\@whileswnoop)
134 % fi
135 % \@nextwhile {SWITCH BODY} \fi
136 % END
137 %
138 % \end{oldcomments}
139 %
140 % \begin{macro}{\@whilenoop}
141 % \begin{macro}{\@whilenum}
142 % \begin{macro}{\@iwhilenum}
143 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
144 % \changes{v1.0g}{1995/08/16}{Removed \cs{@whilenoop}}
145 % \changes{v1.0g}{1995/08/16}{Made defs long}
146 % \begin{macrocode}
147 \long\def\@whilenum#1\do #2{\ifnum #1\relax #2\relax\@iwhilenum{#1\relax
148 #2\relax}\fi}
149 \long\def\@iwhilenum#1{\ifnum #1\expandafter\@iwhilenum
150 \else\expandafter\@gobble\fi{#1}}
151 % \end{macrocode}
152 % \end{macro}
153 % \end{macro}
154 % \end{macro}
155 %
156 % \begin{macro}{\@whiledim}
157 % \begin{macro}{\@iwhiledim}
158 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
159 % \changes{v1.0g}{1995/08/16}{Removed \cs{@whilenoop}}
160 % \changes{v1.0g}{1995/08/16}{Made defs long}
161 % \begin{macrocode}
162 \long\def\@whiledim#1\do #2{\ifdim #1\relax#2\@iwhiledim{#1\relax#2}\fi}
163 \long\def\@iwhiledim#1{\ifdim #1\expandafter\@iwhiledim
164 \else\expandafter\@gobble\fi{#1}}
165 % \end{macrocode}
166 % \end{macro}
167 % \end{macro}
168 %
169 % \begin{macro}{\@whileswnoop}
170 % \begin{macro}{\@whilesw}
171 % \begin{macro}{\@iwhilesw}
172 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
173 % \changes{v1.0g}{1995/08/16}{Removed \cs{@whileswnoop}}
174 % \begin{macrocode}
175 \long\def\@whilesw#1\fi#2{#1#2\@iwhilesw{#1#2}\fi\fi}
176 \long\def\@iwhilesw#1\fi{#1\expandafter\@iwhilesw
177 \else\@gobbletwo\fi{#1}\fi}
178 % \end{macrocode}
179 % \end{macro}
180 % \end{macro}
181 % \end{macro}
182 %
183 % \begin{oldcomments}
184 %
185 % \@for NAME := LIST \do {BODY} ==
186 % BEGIN \@forloop expand(LIST),\@nil,\@nil \@@ NAME {BODY} END
187 %
188 % \@forloop CAR, CARCDR, CDRCDR \@@ NAME {BODY} ==
189 % BEGIN
190 % NAME = CAR
191 % if def(NAME) = def(\@nnil)
192 % else BODY;
193 % NAME = CARCDR
194 % if def(NAME) = def(\@nnil)
195 % else BODY
196 % \@iforloop CDRCDR \@@ NAME \do {BODY}
197 % fi
198 % fi
199 % END
200 %
201 % \@iforloop CAR, CDR \@@ NAME {BODY} =
202 % NAME = CAR
203 % if def(NAME) = def(\@nnil)
204 % then \@nextwhile = def(\@fornoop)
205 % else BODY ;
206 % \@nextwhile = def(\@iforloop)
207 % fi
208 % \@nextwhile name cdr {body}
209 %
210 % \@tfor NAME := LIST \do {BODY}
211 % = \@tforloop LIST \@nil \@@ NAME {BODY}
212 %
213 % \@tforloop car cdr \@@ name {body} =
214 % name = car
215 % if def(name) = def(\@nnil)
216 % then \@nextwhile == \@fornoop
217 % else body ;
218 % \@nextwhile == \@forloop
219 % fi
220 % \@nextwhile name cdr {body}
221 % \end{oldcomments}
222 %
223 % \begin{macro}{\@nnil}
224 % \begin{macrocode}
225 \def\@nnil{\@nil}
226 % \end{macrocode}
227 % \end{macro}
228 %
229 % \begin{macro}{\@empty}
230 % \begin{macrocode}
231 \def\@empty{}
232 % \end{macrocode}
233 % \end{macro}
234 %
235 % \begin{macro}{\@fornoop}
236 % \changes{v1.0g}{1995/08/16}{Made defs long}
237 % \changes{v1.0h}{2007/08/06}{Really make defs long}
238 % \begin{macrocode}
239 \long\def\@fornoop#1\@@#2#3{}
240 % \end{macrocode}
241 % \end{macro}
242 %
243 % \begin{macro}{\@for}
244 % \changes{v1.0d}{1995/04/24}
245 % {Dont expand second argument with \cs{edef}: /1317 (DPC)}
246 % \begin{macrocode}
247 \long\def\@for#1:=#2\do#3{%
248 \expandafter\def\expandafter\@fortmp\expandafter{#2}%
249 \ifx\@fortmp\@empty \else
250 \expandafter\@forloop#2,\@nil,\@nil\@@#1{#3}\fi}
251 % \end{macrocode}
252 % \end{macro}
253 %
254 % \begin{macro}{\@forloop}
255 % \changes{v1.0g}{1995/08/16}{Made defs long}
256 % \begin{macrocode}
257 \long\def\@forloop#1,#2,#3\@@#4#5{\def#4{#1}\ifx #4\@nnil \else
258 #5\def#4{#2}\ifx #4\@nnil \else#5\@iforloop #3\@@#4{#5}\fi\fi}
259 % \end{macrocode}
260 % \end{macro}
261 %
262 % \begin{macro}{\@iforloop}
263 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
264 % \changes{v1.0g}{1995/08/16}{Made defs long}
265 % \begin{macrocode}
266 \long\def\@iforloop#1,#2\@@#3#4{\def#3{#1}\ifx #3\@nnil
267 \expandafter\@fornoop \else
268 #4\relax\expandafter\@iforloop\fi#2\@@#3{#4}}
269 % \end{macrocode}
270 % \end{macro}
271 %
272 % \begin{macro}{\@tfor}
273 % \changes{LaTeX209}{1991/10/17}
274 % {(Rms) \cs{xdef} replaced by \cs{def}
275 % (See FMi's array.doc)}
276 % \changes{v1.0c}{1994/03/13}
277 % {(DPC) Add \cs{@tf@r} so a single group is
278 % correctly treated.}
279 % \changes{v1.0f}{1995/07/09}{Reimplemented using Kabelschacht method}
280 % \changes{v1.0g}{1995/08/16}{Made defs long}
281 % \begin{macrocode}
282 \def\@tfor#1:={\@tf@r#1 }
283 \long\def\@tf@r#1#2\do#3{\def\@fortmp{#2}\ifx\@fortmp\space\else
284 \@tforloop#2\@nil\@nil\@@#1{#3}\fi}
285 \long\def\@tforloop#1#2\@@#3#4{\def#3{#1}\ifx #3\@nnil
286 \expandafter\@fornoop \else
287 #4\relax\expandafter\@tforloop\fi#2\@@#3{#4}}
288 % \end{macrocode}
289 % \end{macro}
290 %
291 % \begin{macro}{\@break@tfor}
292 % Break out of a |\@tfor| loop. This should be called \emph{inside}
293 % the scope of an |\if|. See |\@iffileonpath| for an example.
294 % \changes{v1.0l}{1994/05/02}{Macro added (from ltfiles.dtx)}
295 % \changes{v1.0g}{1995/08/16}{Made long}
296 % \begin{macrocode}
297 \long\def\@break@tfor#1\@@#2#3{\fi\fi}
298 % \end{macrocode}
299 % \end{macro}
300 %
301 % \begin{macro}{\@removeelement}
302 % Removes an element from a comma-separated list and puts it into
303 % a control sequence, called as
304 % |\@removeelement{|\meta{element}|}{|\meta{list}|}{|\meta{cs}|}|.
305 % Due to the implementation method the \meta{element} is not allowed
306 % to contain braces.
307 % \begin{macrocode}
308 \def\@removeelement#1#2#3{%
309 \def\reserved@a##1,#1,##2\reserved@a{##1,##2\reserved@b}%
310 \def\reserved@b##1,\reserved@b##2\reserved@b{%
311 \ifx,##1\@empty\else##1\fi}%
312 \edef#3{%
313 \expandafter\reserved@b\reserved@a,#2,\reserved@b,#1,\reserved@a}}
314 % \end{macrocode}
315 % \end{macro}
316 %
317 %
318 % \changes{v1.0e}{1995/04/29}{Removed unused defs for
319 % \cs{@setprotect} and \cs{@resetprotect}}
320 % \changes{v1.0e}{1995/04/29}{Moved init of \cs{protect}
321 % to ltdefns.dtx}
322 % \begin{macrocode}
323 %</2ekernel>
324 % \end{macrocode}
325 %
326 %\Finale
327 \endinput