:   '''[tcl::unsupported]::inject''' ''coroName cmd'' ?''arg1 arg2 ...''?

[AMG]: What is this new command?  This [http://core.tcl.tk/tcl/info/988bbef5f1210c85109a439c6ccbb88beacd775d] appears to be the initial check-in, which says that it takes arguments [[`::tcl::unsupported::inject coroname command args`]] and makes the named command be the first thing the coroutine does the next time it's resumed.

[DKF]: It's supposed to be a mechanism for introducing a command into a coroutine that allows for things like debugging. It is, however, considered rather too difficult to use (or explain the exact semantics of) in its current incarnation.

[APN]: Interactive example:

======
% coroutine mycoro apply {{} { while {1} {puts "Hoo ha" ; yield} }}
Hoo ha
% mycoro
Hoo ha
% tcl::unsupported::inject mycoro puts Injected!
% mycoro
Injected!
Hoo ha
% mycoro
Hoo ha
% tcl::unsupported::inject mycoro return Done!
% mycoro
Done!
% mycoro
invalid command name "mycoro"
======

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