Re: After I overload "switch" command, how can I get back the original "switch" function back?

pheobe wrote:
I am planning to overlad "switch" command in my application, and use
it do something, yet after that, how can I get back the original
function of "switch" ? I don't want to use the overlad "switch" all
through my appliction.

You have to take action *before* you overload the [switch] command. To
do this, you use the [rename] command to change the original [switch] to
something else, before creating the replacement procedure. Once you've
finished with the overload, [rename] the saved real [switch] command
back to its normal name. Like this:

rename switch switch_savedForLaterByPheobe
proc switch args {
...
}
# do stuff with the custom [switch] here before restoring...
rename switch_savedForLaterByPheobe switch

If the code that is using your modified [switch] is in a namespace other
than the default global one, another technique is possible. Simply
create the modified [switch] inside that other namespace; it will then
overload inside the procedures in that namespace automatically without
affecting any commands elsewhere.

namespace eval someNs {
proc yourProcedure ... ...
proc switch args {
...
}
}
# Invoke command that uses the custom [switch]
someNs::yourProcedure ...

Note that you can cause the code in the namespace to use the standard
[switch] by just deleting or renaming the namespace's local switch
command, like this:

# To delete, do this:
rename someNs::switch {}
# To move out of the way, do this:
rename someNs::switch someNs::switch_outOfService

(Tcl 8.5 has some extra techniques that are more-powerful variants on
this theme, but the schemes already described will continue to work for
at least the foreseeable future.)

Donal.
.

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