2 '\" Copyright (c) 1993 The Regents of the University of California.
3 '\" Copyright (c) 1994-1997 Sun Microsystems, Inc.
5 '\" See the file "license.terms" for information on usage and redistribution
6 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
8 .TH uplevel n "" Tcl "Tcl Built-In Commands"
9 .\" The -*- nroff -*- definitions below are for supplemental macros used
10 .\" in Tcl/Tk manual entries.
12 .\" .AP type name in/out ?indent?
13 .\" Start paragraph describing an argument to a library procedure.
14 .\" type is type of argument (int, etc.), in/out is either "in", "out",
15 .\" or "in/out" to describe whether procedure reads or modifies arg,
16 .\" and indent is equivalent to second arg of .IP (shouldn't ever be
17 .\" needed; use .AS below instead)
20 .\" Give maximum sizes of arguments for setting tab stops. Type and
21 .\" name are examples of largest possible arguments that will be passed
22 .\" to .AP later. If args are omitted, default tab stops are used.
25 .\" Start box enclosure. From here until next .BE, everything will be
26 .\" enclosed in one large box.
29 .\" End of box enclosure.
32 .\" Begin code excerpt.
37 .\" .VS ?version? ?br?
38 .\" Begin vertical sidebar, for use in marking newly-changed parts
39 .\" of man pages. The first argument is ignored and used for recording
40 .\" the version when the .VS was added, so that the sidebars can be
41 .\" found and removed when they reach a certain age. If another argument
42 .\" is present, then a line break is forced before starting the sidebar.
45 .\" End of vertical sidebar.
48 .\" Begin an indented unfilled display.
51 .\" End of indented unfilled display.
54 .\" Start of list of standard options for a Tk widget. The manpage
55 .\" argument defines where to look up the standard options; if
56 .\" omitted, defaults to "options". The options follow on successive
57 .\" lines, in three columns separated by tabs.
60 .\" End of list of standard options for a Tk widget.
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.
69 .\" Print arg1 underlined, then print arg2 normally.
72 .\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
75 .\" Print an open parenthesis, arg1 in quotes, then arg2 normally
76 .\" (for trailing punctuation) and then a closing parenthesis.
78 .\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
82 .\" # Start an argument description
86 . ie !"\\$2"" .TP \\n()Cu
91 \&\\$1 \\fI\\$2\\fP (\\$3)
104 .\" # define tabbing values for .AP
107 .if !"\\$1"" .nr )A \\w'\\$1'u+3n
110 .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n
111 .nr )C \\n()Bu+\\w'(in/out)'u+2n
113 .AS Tcl_Interp Tcl_CreateInterp in/out
114 .\" # BS - start boxed text
115 .\" # ^y = starting y location
123 .if n \l'\\n(.lu\(ul'
126 .\" # BE - end boxed text (draw box now)
131 .ie n \l'\\n(^lu\(ul'
133 .\" Draw four-sided box normally, but don't draw top of
134 .\" box if the box started on an earlier page.
136 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
139 \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul'
146 .\" # VS - start vertical sidebar
147 .\" # ^Y = starting y location
148 .\" # ^v = 1 (for troff; for nroff this doesn't matter)
152 .ie n 'mc \s12\(br\s0
155 .\" # VE - end of vertical sidebar
163 \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n'
170 .\" # Special macro to handle page bottom: finish off current
171 .\" # box/sidebar if in box/sidebar mode, then invoked standard
172 .\" # page bottom macro.
179 .\" Draw three-sided box if this is the box's first page,
180 .\" draw two sides but no top otherwise.
181 .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
182 .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c
185 .nr ^x \\n(^tu+1v-\\n(^Yu
186 \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c
199 .\" # DS - begin display
205 .\" # DE - end display
211 .\" # SO - start of list of standard options
213 'ie '\\$1'' .ds So \\fBoptions\\fR
214 'el .ds So \\fB\\$1\\fR
215 .SH "STANDARD OPTIONS"
221 .\" # SE - end of list of standard options
226 See the \\*(So manual entry for details on the standard options.
228 .\" # OP - start of full description for a single option
233 Command-Line Name: \\fB\\$1\\fR
234 Database Name: \\fB\\$2\\fR
235 Database Class: \\fB\\$3\\fR
239 .\" # CS - begin code excerpt
245 .\" # CE - end code excerpt
250 .\" # UL - underline word
254 .\" # QW - apply quotation marks to word
256 .ie '\\*(lq'"' ``\\$1''\\$2
257 .\"" fix emacs highlighting
258 .el \\*(lq\\$1\\*(rq\\$2
260 .\" # PQ - apply parens and quotation marks to word
262 .ie '\\*(lq'"' (``\\$1''\\$2)\\$3
263 .\"" fix emacs highlighting
264 .el (\\*(lq\\$1\\*(rq\\$2)\\$3
266 .\" # QR - quoted range
268 .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
269 .\"" fix emacs highlighting
270 .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
272 .\" # MT - "empty" string
277 '\" Note: do not modify the .SH NAME line immediately below!
279 uplevel \- Execute a script in a different stack frame
281 \fBuplevel \fR?\fIlevel\fR?\fI arg \fR?\fIarg ...\fR?
285 All of the \fIarg\fR arguments are concatenated as if they had
286 been passed to \fBconcat\fR; the result is then evaluated in the
287 variable context indicated by \fIlevel\fR. \fBUplevel\fR returns
288 the result of that evaluation.
290 If \fIlevel\fR is an integer then
291 it gives a distance (up the procedure calling stack) to move before
292 executing the command. If \fIlevel\fR consists of \fB#\fR followed by
293 a number then the number gives an absolute level number. If \fIlevel\fR
294 is omitted then it defaults to \fB1\fR. \fILevel\fR cannot be
295 defaulted if the first \fIcommand\fR argument starts with a digit or \fB#\fR.
297 For example, suppose that procedure \fBa\fR was invoked
298 from top-level, and that it called \fBb\fR, and that \fBb\fR called \fBc\fR.
299 Suppose that \fBc\fR invokes the \fBuplevel\fR command. If \fIlevel\fR
300 is \fB1\fR or \fB#2\fR or omitted, then the command will be executed
301 in the variable context of \fBb\fR. If \fIlevel\fR is \fB2\fR or \fB#1\fR
302 then the command will be executed in the variable context of \fBa\fR.
303 If \fIlevel\fR is \fB3\fR or \fB#0\fR then the command will be executed
304 at top-level (only global variables will be visible).
306 The \fBuplevel\fR command causes the invoking procedure to disappear
307 from the procedure calling stack while the command is being executed.
308 In the above example, suppose \fBc\fR invokes the command
311 \fBuplevel\fR 1 {set x 43; d}
314 where \fBd\fR is another Tcl procedure. The \fBset\fR command will
315 modify the variable \fBx\fR in \fBb\fR's context, and \fBd\fR will execute
316 at level 3, as if called from \fBb\fR. If it in turn executes
320 \fBuplevel\fR {set x 42}
323 then the \fBset\fR command will modify the same variable \fBx\fR in \fBb\fR's
324 context: the procedure \fBc\fR does not appear to be on the call stack
325 when \fBd\fR is executing. The \fBinfo level\fR command may
326 be used to obtain the level of the current procedure.
328 \fBUplevel\fR makes it possible to implement new control
329 constructs as Tcl procedures (for example, \fBuplevel\fR could
330 be used to implement the \fBwhile\fR construct as a Tcl procedure).
332 The \fBnamespace eval\fR and \fBapply\fR commands offer other ways
333 (besides procedure calls) that the Tcl naming context can change.
334 They add a call frame to the stack to represent the namespace context.
335 This means each \fBnamespace eval\fR command
336 counts as another call level for \fBuplevel\fR and \fBupvar\fR commands.
337 For example, \fBinfo level 1\fR will return a list
338 describing a command that is either
339 the outermost procedure call or the outermost \fBnamespace eval\fR command.
340 Also, \fBuplevel #0\fR evaluates a script
341 at top-level in the outermost namespace (the global namespace).
343 As stated above, the \fBuplevel\fR command is useful for creating new
344 control constructs. This example shows how (without error handling)
345 it can be used to create a \fBdo\fR command that is the counterpart of
346 \fBwhile\fR except for always performing the test after running the
350 proc do {body while condition} {
351 if {$while ne "while"} {
352 error "required word missing"
354 set conditionCmd [list expr $condition]
356 \fBuplevel\fR 1 $body
357 if {![\fBuplevel\fR 1 $conditionCmd]} {
364 apply(n), namespace(n), upvar(n)
366 context, level, namespace, stack frame, variable