Creates a scoped value for the specified command and its associated arg arguments. A scoped value is a list with three elements: the "@scope" keyword, a namespace context, and a value string. For example, the command
namespace foo {
code puts "Hello World!"
}
@scope ::foo {puts {Hello World!}}
Extensions like Tk execute ordinary code fragments in the global namespace. A scoped value captures a code fragment together with its namespace context in a way that allows it to be executed properly later. It is needed, for example, to wrap up code fragments when a Tk widget is used within a namespace:
namespace foo {
private proc report {mesg} {
puts "click: $mesg"
}
button .b1 -text "Push Me" -command [code report "Hello World!"]
pack .b1
}
Also, note that the code command preserves the integrity of arguments on the command line. This makes it a natural replacement for the list command, which is often used to format Tcl code fragments. In other words, instead of using the list command like this:
after 1000 [list puts "Hello $name!"]
after 1000 [code puts "Hello $name!"]
Scoped commands can be invoked like ordinary code fragments, with or without the eval command. For example, the following statements work properly:
set cmd {@scope ::foo .b1}
$cmd configure -background red
set opts {-bg blue -fg white}
eval $cmd configure $opts
@scope ::foo {report {Hello World!}}