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1 | '\" |
2 | '\" Copyright (c) 1993 The Regents of the University of California. | |
3 | '\" Copyright (c) 1994-1997 Sun Microsystems, Inc. | |
4 | '\" | |
5 | '\" See the file "license.terms" for information on usage and redistribution | |
6 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. | |
7 | '\" | |
8 | '\" RCS: @(#) $Id: switch.n,v 1.5.18.1 2004/10/27 14:23:58 dkf Exp $ | |
9 | '\" | |
10 | '\" The definitions below are for supplemental macros used in Tcl/Tk | |
11 | '\" manual entries. | |
12 | '\" | |
13 | '\" .AP type name in/out ?indent? | |
14 | '\" Start paragraph describing an argument to a library procedure. | |
15 | '\" type is type of argument (int, etc.), in/out is either "in", "out", | |
16 | '\" or "in/out" to describe whether procedure reads or modifies arg, | |
17 | '\" and indent is equivalent to second arg of .IP (shouldn't ever be | |
18 | '\" needed; use .AS below instead) | |
19 | '\" | |
20 | '\" .AS ?type? ?name? | |
21 | '\" Give maximum sizes of arguments for setting tab stops. Type and | |
22 | '\" name are examples of largest possible arguments that will be passed | |
23 | '\" to .AP later. If args are omitted, default tab stops are used. | |
24 | '\" | |
25 | '\" .BS | |
26 | '\" Start box enclosure. From here until next .BE, everything will be | |
27 | '\" enclosed in one large box. | |
28 | '\" | |
29 | '\" .BE | |
30 | '\" End of box enclosure. | |
31 | '\" | |
32 | '\" .CS | |
33 | '\" Begin code excerpt. | |
34 | '\" | |
35 | '\" .CE | |
36 | '\" End code excerpt. | |
37 | '\" | |
38 | '\" .VS ?version? ?br? | |
39 | '\" Begin vertical sidebar, for use in marking newly-changed parts | |
40 | '\" of man pages. The first argument is ignored and used for recording | |
41 | '\" the version when the .VS was added, so that the sidebars can be | |
42 | '\" found and removed when they reach a certain age. If another argument | |
43 | '\" is present, then a line break is forced before starting the sidebar. | |
44 | '\" | |
45 | '\" .VE | |
46 | '\" End of vertical sidebar. | |
47 | '\" | |
48 | '\" .DS | |
49 | '\" Begin an indented unfilled display. | |
50 | '\" | |
51 | '\" .DE | |
52 | '\" End of indented unfilled display. | |
53 | '\" | |
54 | '\" .SO | |
55 | '\" Start of list of standard options for a Tk widget. The | |
56 | '\" options follow on successive lines, in four columns separated | |
57 | '\" by tabs. | |
58 | '\" | |
59 | '\" .SE | |
60 | '\" End of list of standard options for a Tk widget. | |
61 | '\" | |
62 | '\" .OP cmdName dbName dbClass | |
63 | '\" Start of description of a specific option. cmdName gives the | |
64 | '\" option's name as specified in the class command, dbName gives | |
65 | '\" the option's name in the option database, and dbClass gives | |
66 | '\" the option's class in the option database. | |
67 | '\" | |
68 | '\" .UL arg1 arg2 | |
69 | '\" Print arg1 underlined, then print arg2 normally. | |
70 | '\" | |
71 | '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ | |
72 | '\" | |
73 | '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. | |
74 | .if t .wh -1.3i ^B | |
75 | .nr ^l \n(.l | |
76 | .ad b | |
77 | '\" # Start an argument description | |
78 | .de AP | |
79 | .ie !"\\$4"" .TP \\$4 | |
80 | .el \{\ | |
81 | . ie !"\\$2"" .TP \\n()Cu | |
82 | . el .TP 15 | |
83 | .\} | |
84 | .ta \\n()Au \\n()Bu | |
85 | .ie !"\\$3"" \{\ | |
86 | \&\\$1 \\fI\\$2\\fP (\\$3) | |
87 | .\".b | |
88 | .\} | |
89 | .el \{\ | |
90 | .br | |
91 | .ie !"\\$2"" \{\ | |
92 | \&\\$1 \\fI\\$2\\fP | |
93 | .\} | |
94 | .el \{\ | |
95 | \&\\fI\\$1\\fP | |
96 | .\} | |
97 | .\} | |
98 | .. | |
99 | '\" # define tabbing values for .AP | |
100 | .de AS | |
101 | .nr )A 10n | |
102 | .if !"\\$1"" .nr )A \\w'\\$1'u+3n | |
103 | .nr )B \\n()Au+15n | |
104 | .\" | |
105 | .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n | |
106 | .nr )C \\n()Bu+\\w'(in/out)'u+2n | |
107 | .. | |
108 | .AS Tcl_Interp Tcl_CreateInterp in/out | |
109 | '\" # BS - start boxed text | |
110 | '\" # ^y = starting y location | |
111 | '\" # ^b = 1 | |
112 | .de BS | |
113 | .br | |
114 | .mk ^y | |
115 | .nr ^b 1u | |
116 | .if n .nf | |
117 | .if n .ti 0 | |
118 | .if n \l'\\n(.lu\(ul' | |
119 | .if n .fi | |
120 | .. | |
121 | '\" # BE - end boxed text (draw box now) | |
122 | .de BE | |
123 | .nf | |
124 | .ti 0 | |
125 | .mk ^t | |
126 | .ie n \l'\\n(^lu\(ul' | |
127 | .el \{\ | |
128 | .\" Draw four-sided box normally, but don't draw top of | |
129 | .\" box if the box started on an earlier page. | |
130 | .ie !\\n(^b-1 \{\ | |
131 | \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' | |
132 | .\} | |
133 | .el \}\ | |
134 | \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' | |
135 | .\} | |
136 | .\} | |
137 | .fi | |
138 | .br | |
139 | .nr ^b 0 | |
140 | .. | |
141 | '\" # VS - start vertical sidebar | |
142 | '\" # ^Y = starting y location | |
143 | '\" # ^v = 1 (for troff; for nroff this doesn't matter) | |
144 | .de VS | |
145 | .if !"\\$2"" .br | |
146 | .mk ^Y | |
147 | .ie n 'mc \s12\(br\s0 | |
148 | .el .nr ^v 1u | |
149 | .. | |
150 | '\" # VE - end of vertical sidebar | |
151 | .de VE | |
152 | .ie n 'mc | |
153 | .el \{\ | |
154 | .ev 2 | |
155 | .nf | |
156 | .ti 0 | |
157 | .mk ^t | |
158 | \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' | |
159 | .sp -1 | |
160 | .fi | |
161 | .ev | |
162 | .\} | |
163 | .nr ^v 0 | |
164 | .. | |
165 | '\" # Special macro to handle page bottom: finish off current | |
166 | '\" # box/sidebar if in box/sidebar mode, then invoked standard | |
167 | '\" # page bottom macro. | |
168 | .de ^B | |
169 | .ev 2 | |
170 | 'ti 0 | |
171 | 'nf | |
172 | .mk ^t | |
173 | .if \\n(^b \{\ | |
174 | .\" Draw three-sided box if this is the box's first page, | |
175 | .\" draw two sides but no top otherwise. | |
176 | .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c | |
177 | .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c | |
178 | .\} | |
179 | .if \\n(^v \{\ | |
180 | .nr ^x \\n(^tu+1v-\\n(^Yu | |
181 | \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c | |
182 | .\} | |
183 | .bp | |
184 | 'fi | |
185 | .ev | |
186 | .if \\n(^b \{\ | |
187 | .mk ^y | |
188 | .nr ^b 2 | |
189 | .\} | |
190 | .if \\n(^v \{\ | |
191 | .mk ^Y | |
192 | .\} | |
193 | .. | |
194 | '\" # DS - begin display | |
195 | .de DS | |
196 | .RS | |
197 | .nf | |
198 | .sp | |
199 | .. | |
200 | '\" # DE - end display | |
201 | .de DE | |
202 | .fi | |
203 | .RE | |
204 | .sp | |
205 | .. | |
206 | '\" # SO - start of list of standard options | |
207 | .de SO | |
208 | .SH "STANDARD OPTIONS" | |
209 | .LP | |
210 | .nf | |
211 | .ta 5.5c 11c | |
212 | .ft B | |
213 | .. | |
214 | '\" # SE - end of list of standard options | |
215 | .de SE | |
216 | .fi | |
217 | .ft R | |
218 | .LP | |
219 | See the \\fBoptions\\fR manual entry for details on the standard options. | |
220 | .. | |
221 | '\" # OP - start of full description for a single option | |
222 | .de OP | |
223 | .LP | |
224 | .nf | |
225 | .ta 4c | |
226 | Command-Line Name: \\fB\\$1\\fR | |
227 | Database Name: \\fB\\$2\\fR | |
228 | Database Class: \\fB\\$3\\fR | |
229 | .fi | |
230 | .IP | |
231 | .. | |
232 | '\" # CS - begin code excerpt | |
233 | .de CS | |
234 | .RS | |
235 | .nf | |
236 | .ta .25i .5i .75i 1i | |
237 | .. | |
238 | '\" # CE - end code excerpt | |
239 | .de CE | |
240 | .fi | |
241 | .RE | |
242 | .. | |
243 | .de UL | |
244 | \\$1\l'|0\(ul'\\$2 | |
245 | .. | |
246 | .TH switch n 7.0 Tcl "Tcl Built-In Commands" | |
247 | .BS | |
248 | '\" Note: do not modify the .SH NAME line immediately below! | |
249 | .SH NAME | |
250 | switch \- Evaluate one of several scripts, depending on a given value | |
251 | .SH SYNOPSIS | |
252 | \fBswitch \fR?\fIoptions\fR?\fI string pattern body \fR?\fIpattern body \fR...? | |
253 | .sp | |
254 | \fBswitch \fR?\fIoptions\fR?\fI string \fR{\fIpattern body \fR?\fIpattern body \fR...?} | |
255 | .BE | |
256 | ||
257 | .SH DESCRIPTION | |
258 | .PP | |
259 | The \fBswitch\fR command matches its \fIstring\fR argument against each of | |
260 | the \fIpattern\fR arguments in order. | |
261 | As soon as it finds a \fIpattern\fR that matches \fIstring\fR it | |
262 | evaluates the following \fIbody\fR argument by passing it recursively | |
263 | to the Tcl interpreter and returns the result of that evaluation. | |
264 | If the last \fIpattern\fR argument is \fBdefault\fR then it matches | |
265 | anything. | |
266 | If no \fIpattern\fR argument | |
267 | matches \fIstring\fR and no default is given, then the \fBswitch\fR | |
268 | command returns an empty string. | |
269 | .PP | |
270 | If the initial arguments to \fBswitch\fR start with \fB\-\fR then | |
271 | they are treated as options. The following options are | |
272 | currently supported: | |
273 | .TP 10 | |
274 | \fB\-exact\fR | |
275 | Use exact matching when comparing \fIstring\fR to a pattern. This | |
276 | is the default. | |
277 | .TP 10 | |
278 | \fB\-glob\fR | |
279 | When matching \fIstring\fR to the patterns, use glob-style matching | |
280 | (i.e. the same as implemented by the \fBstring match\fR command). | |
281 | .TP 10 | |
282 | \fB\-regexp\fR | |
283 | When matching \fIstring\fR to the patterns, use regular | |
284 | expression matching | |
285 | (as described in the \fBre_syntax\fR reference page). | |
286 | .TP 10 | |
287 | \fB\-\|\-\fR | |
288 | Marks the end of options. The argument following this one will | |
289 | be treated as \fIstring\fR even if it starts with a \fB\-\fR. | |
290 | .PP | |
291 | Two syntaxes are provided for the \fIpattern\fR and \fIbody\fR arguments. | |
292 | The first uses a separate argument for each of the patterns and commands; | |
293 | this form is convenient if substitutions are desired on some of the | |
294 | patterns or commands. | |
295 | The second form places all of the patterns and commands together into | |
296 | a single argument; the argument must have proper list structure, with | |
297 | the elements of the list being the patterns and commands. | |
298 | The second form makes it easy to construct multi-line switch commands, | |
299 | since the braces around the whole list make it unnecessary to include a | |
300 | backslash at the end of each line. | |
301 | Since the \fIpattern\fR arguments are in braces in the second form, | |
302 | no command or variable substitutions are performed on them; this makes | |
303 | the behavior of the second form different than the first form in some | |
304 | cases. | |
305 | .PP | |
306 | If a \fIbody\fR is specified as ``\fB\-\fR'' it means that the \fIbody\fR | |
307 | for the next pattern should also be used as the body for this | |
308 | pattern (if the next pattern also has a body of ``\fB\-\fR'' | |
309 | then the body after that is used, and so on). | |
310 | This feature makes it possible to share a single \fIbody\fR among | |
311 | several patterns. | |
312 | .PP | |
313 | Beware of how you place comments in \fBswitch\fR commands. Comments | |
314 | should only be placed \fBinside\fR the execution body of one of the | |
315 | patterns, and not intermingled with the patterns. | |
316 | .SH "EXAMPLES" | |
317 | The \fBswitch\fR command can match against variables and not just | |
318 | literals, as shown here (the result is \fI2\fR): | |
319 | .CS | |
320 | set foo "abc" | |
321 | \fBswitch\fR abc a \- b {expr 1} $foo {expr 2} default {expr 3} | |
322 | .CE | |
323 | .PP | |
324 | Using glob matching and the fall-through body is an alternative to | |
325 | writing regular expressions with alternations, as can be seen here | |
326 | (this returns \fI1\fR): | |
327 | .CS | |
328 | \fBswitch\fR \-glob aaab { | |
329 | a*b \- | |
330 | b {expr 1} | |
331 | a* {expr 2} | |
332 | default {expr 3} | |
333 | } | |
334 | .CE | |
335 | .PP | |
336 | Whenever nothing matches, the \fBdefault\fR clause (which must be | |
337 | last) is taken. This example has a result of \fI3\fR: | |
338 | .CS | |
339 | \fBswitch\fR xyz { | |
340 | a \- | |
341 | b { | |
342 | # Correct Comment Placement | |
343 | expr 1 | |
344 | } | |
345 | c { | |
346 | expr 2 | |
347 | } | |
348 | default { | |
349 | expr 3 | |
350 | } | |
351 | } | |
352 | .CE | |
353 | ||
354 | .SH "SEE ALSO" | |
355 | for(n), if(n), regexp(n) | |
356 | ||
357 | .SH KEYWORDS | |
358 | switch, match, regular expression |