| '\" |
| '\" Copyright (c) 1993-1998 Lucent Technologies, Inc. |
| '\" |
| '\" See the file "license.terms" for information on usage and redistribution |
| '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| '\" |
| '\" RCS: $Id: scope.n,v 1.5 1998/08/23 16:32:23 stanton Exp $ |
| '\" |
| '\" The definitions below are for supplemental macros used in Tcl/Tk |
| '\" manual entries. |
| '\" |
| '\" .AP type name in/out ?indent? |
| '\" Start paragraph describing an argument to a library procedure. |
| '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| '\" or "in/out" to describe whether procedure reads or modifies arg, |
| '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| '\" needed; use .AS below instead) |
| '\" |
| '\" .AS ?type? ?name? |
| '\" Give maximum sizes of arguments for setting tab stops. Type and |
| '\" name are examples of largest possible arguments that will be passed |
| '\" to .AP later. If args are omitted, default tab stops are used. |
| '\" |
| '\" .BS |
| '\" Start box enclosure. From here until next .BE, everything will be |
| '\" enclosed in one large box. |
| '\" |
| '\" .BE |
| '\" End of box enclosure. |
| '\" |
| '\" .CS |
| '\" Begin code excerpt. |
| '\" |
| '\" .CE |
| '\" End code excerpt. |
| '\" |
| '\" .VS ?version? ?br? |
| '\" Begin vertical sidebar, for use in marking newly-changed parts |
| '\" of man pages. The first argument is ignored and used for recording |
| '\" the version when the .VS was added, so that the sidebars can be |
| '\" found and removed when they reach a certain age. If another argument |
| '\" is present, then a line break is forced before starting the sidebar. |
| '\" |
| '\" .VE |
| '\" End of vertical sidebar. |
| '\" |
| '\" .DS |
| '\" Begin an indented unfilled display. |
| '\" |
| '\" .DE |
| '\" End of indented unfilled display. |
| '\" |
| '\" .SO |
| '\" Start of list of standard options for a Tk widget. The |
| '\" options follow on successive lines, in four columns separated |
| '\" by tabs. |
| '\" |
| '\" .SE |
| '\" End of list of standard options for a Tk widget. |
| '\" |
| '\" .OP cmdName dbName dbClass |
| '\" Start of description of a specific option. cmdName gives the |
| '\" option's name as specified in the class command, dbName gives |
| '\" the option's name in the option database, and dbClass gives |
| '\" the option's class in the option database. |
| '\" |
| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
| '\" |
| '\" SCCS: @(#) man.macros 1.9 97/08/22 18:50:59 |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
| .nr ^l \n(.l |
| .ad b |
| '\" # Start an argument description |
| .de AP |
| .ie !"\\$4"" .TP \\$4 |
| .el \{\ |
| . ie !"\\$2"" .TP \\n()Cu |
| . el .TP 15 |
| .\} |
| .ie !"\\$3"" \{\ |
| .ta \\n()Au \\n()Bu |
| \&\\$1 \\fI\\$2\\fP (\\$3) |
| .\".b |
| .\} |
| .el \{\ |
| .br |
| .ie !"\\$2"" \{\ |
| \&\\$1 \\fI\\$2\\fP |
| .\} |
| .el \{\ |
| \&\\fI\\$1\\fP |
| .\} |
| .\} |
| .. |
| '\" # define tabbing values for .AP |
| .de AS |
| .nr )A 10n |
| .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| .nr )B \\n()Au+15n |
| .\" |
| .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| .. |
| .AS Tcl_Interp Tcl_CreateInterp in/out |
| '\" # BS - start boxed text |
| '\" # ^y = starting y location |
| '\" # ^b = 1 |
| .de BS |
| .br |
| .mk ^y |
| .nr ^b 1u |
| .if n .nf |
| .if n .ti 0 |
| .if n \l'\\n(.lu\(ul' |
| .if n .fi |
| .. |
| '\" # BE - end boxed text (draw box now) |
| .de BE |
| .nf |
| .ti 0 |
| .mk ^t |
| .ie n \l'\\n(^lu\(ul' |
| .el \{\ |
| .\" Draw four-sided box normally, but don't draw top of |
| .\" box if the box started on an earlier page. |
| .ie !\\n(^b-1 \{\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .el \}\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .\} |
| .fi |
| .br |
| .nr ^b 0 |
| .. |
| '\" # VS - start vertical sidebar |
| '\" # ^Y = starting y location |
| '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| .de VS |
| .if !"\\$2"" .br |
| .mk ^Y |
| .ie n 'mc \s12\(br\s0 |
| .el .nr ^v 1u |
| .. |
| '\" # VE - end of vertical sidebar |
| .de VE |
| .ie n 'mc |
| .el \{\ |
| .ev 2 |
| .nf |
| .ti 0 |
| .mk ^t |
| \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| .sp -1 |
| .fi |
| .ev |
| .\} |
| .nr ^v 0 |
| .. |
| '\" # Special macro to handle page bottom: finish off current |
| '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| '\" # page bottom macro. |
| .de ^B |
| .ev 2 |
| 'ti 0 |
| 'nf |
| .mk ^t |
| .if \\n(^b \{\ |
| .\" Draw three-sided box if this is the box's first page, |
| .\" draw two sides but no top otherwise. |
| .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 |
| .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .\} |
| .if \\n(^v \{\ |
| .nr ^x \\n(^tu+1v-\\n(^Yu |
| \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| .\} |
| .bp |
| 'fi |
| .ev |
| .if \\n(^b \{\ |
| .mk ^y |
| .nr ^b 2 |
| .\} |
| .if \\n(^v \{\ |
| .mk ^Y |
| .\} |
| .. |
| '\" # DS - begin display |
| .de DS |
| .RS |
| .nf |
| .sp |
| .. |
| '\" # DE - end display |
| .de DE |
| .fi |
| .RE |
| .sp |
| .. |
| '\" # SO - start of list of standard options |
| .de SO |
| .SH "STANDARD OPTIONS" |
| .LP |
| .nf |
| .ta 4c 8c 12c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
| .fi |
| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
| .ta 4c |
| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
| .fi |
| .IP |
| .. |
| '\" # CS - begin code excerpt |
| .de CS |
| .RS |
| .nf |
| .ta .25i .5i .75i 1i |
| .. |
| '\" # CE - end code excerpt |
| .de CE |
| .fi |
| .RE |
| .. |
| .de UL |
| \\$1\l'|0\(ul'\\$2 |
| .. |
| .TH scope n "" itcl "[incr\ Tcl]" |
| .BS |
| '\" Note: do not modify the .SH NAME line immediately below! |
| .SH NAME |
| scope \- capture the namespace context for a variable |
| .SH SYNOPSIS |
| \fBscope \fIname\fR |
| .BE |
| |
| .SH DESCRIPTION |
| .PP |
| Creates a scoped value for the specified \fIname\fR, which must |
| be a variable name. If the \fIname\fR is an instance variable, |
| then the scope command returns a string of the following form: |
| .CS |
| @itcl \fIobject varName\fP |
| .CE |
| This is recognized in any context as an instance variable belonging |
| to \fIobject\fR. So with itcl3.0 and beyond, it is possible to use |
| instance variables in conjunction with widgets. For example, if you |
| have an object with a private variable \fCx\fR, and you can use |
| \fCx\fR in conjunction with the \fC-textvariable\fR option of an |
| entry widget. Before itcl3.0, only common variables could be used |
| in this manner. |
| .PP |
| If the \fIname\fR is not an instance variable, then it must be |
| a common variable or a global variable. In that case, the scope |
| command returns the fully qualified name of the variable, e.g., |
| \fC::foo::bar::x\fR. |
| .PP |
| If the \fIname\fR is not recognized as a variable, the scope |
| command returns an error. |
| .PP |
| Ordinary variable names refer to variables in the global namespace. |
| A scoped value captures a variable name together with its namespace |
| context in a way that allows it to be referenced properly later. |
| It is needed, for example, to wrap up variable names when a Tk |
| widget is used within a namespace: |
| .CS |
| namespace foo { |
| private variable mode 1 |
| |
| radiobutton .rb1 -text "Mode #1" \ |
| -variable [scope mode] -value 1 |
| pack .rb1 |
| |
| radiobutton .rb2 -text "Mode #2" \ |
| -variable [scope mode] -value 2 |
| pack .rb2 |
| } |
| .CE |
| Radiobuttons \fC.rb1\fR and \fC.rb2\fR interact via the variable |
| "mode" contained in the namespace "foo". The \fBscope\fR command |
| guarantees this by returning the fully qualified variable name |
| \fC::foo::mode\fR. |
| .PP |
| You should never use the \fC@itcl\fR syntax directly. For example, |
| it is a bad idea to write code like this: |
| .CS |
| set {@itcl ::fred x} 3 |
| puts "value = ${@itcl ::fred x}" |
| .CE |
| Instead, you should always use the scope command to generate the |
| variable name dynamically. Then, you can pass that name to a widget |
| or to any other bit of code in your program. |
| |
| .SH KEYWORDS |
| code, namespace, variable |