======
# returns an unused procedure name
proc gensym {prefix} {
    tailcall apply {{prefix} {
        string cat $prefix[llength [info commands $prefix*]]
    }} $prefix
}
 
# creates an anonymous coroutine
proc go {cmd args} {
    set name [gensym goro#]
    coroutine $name $cmd {*}$args
    return $name
}
======

Credit for the above code goes to [aspect].

The odd construct with `tailcall apply` is so that [info commands] will be executed in the caller's namespace.

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