Updated 2016-01-25 06:43:04 by pooryorick

rename, a built-in command, renames or removes a command.

Synopsis  edit

rename oldName newName

Documentation  edit

official reference

Description  edit

To remove a command, rename it to the empty string:
rename foo {}

To rename a command to the empty string instead of removing it:
rename foo ::

To rename a command only if a command by the new name doesn't exist:
if {[namespace which newname] eq {}} {
    rename oldname newname

DGP: Be aware that if you rename a command into another namespace, its evaluation context will change to that namespace.
% namespace eval one {
  variable message "I'm in one"
  proc test {} {variable message; return $message}
% namespace eval two {variable message "I'm in two"}
% rename one::test two::test
% two::test
I'm in two

aspect: Also watch out for where you're renaming commands to:
% proc foo args {}
% namespace eval ddd {namespace which -command foo}
% namespace eval ddd {rename foo foo}
% namespace eval ddd {namespace which -command foo}

HaO 2010-04-10: (discussion on CLT): rename or delete from inside targeted proc is allowed:
proc ::runOnceAndDelete {} {
    # do something
    rename ::runOnceAndDelete ""

See Also  edit

wrapping commands
One common use of rename is to replace a command with another comand that calls the original command, performing additional steps before or afterwards. Some examples of this are Overloading widgets, Text variable for text widget, and Forward compatibility.

Page Contributors  edit

Lars H