NAME

scope - capture the namespace context for a variable

SYNOPSIS

itcl::scope name

DESCRIPTION

Creates a scoped value for the specified name, which must be a variable name. If the name is an instance variable, then the scope command returns a string of the following form:

@itcl object varName

If the name 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., ::foo::bar::x.

If the name is not recognized as a variable, the scope command returns an error.

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:

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
}

You should never use the @itcl syntax directly. For example, it is a bad idea to write code like this:

set {@itcl ::fred x} 3
puts "value = ${@itcl ::fred x}"

KEYWORDS

code, namespace, variable