'''[namespace] eval''', evaluates a [script] in a given namespace.



** See Also **

   `[namespace]`:   

   `[eval]`:   



** Synopsis **

    :   '''[namespace] eval''' ''namespace arg'' ?''arg ...''?



** Description **

''arg''s are [concat]enated together with a space between each one in the same
fashion as [eval], and the result is evaluated in the namespace called
''namespace''.  If the namespace does not already exist, it is created. If more
than

If ''namespace'' has leading namespace qualifiers and any leading namespaces do
not exist, they are automatically created.

Unlike `[eval]`, `namespace eval` creates a new level, and `[uplevel]` accesses
the level that called `[namespace eval]`.  In spite of this, `[return]`  within
`[namespace eval]` operates as if it were `[uplevel] return`, i.e., it causes
the caller of `[namespace eval]` to return.  It would probably be more useful
if `[return]` within a `namespace eval` script behaved the way it does within
`[source] ...` script.

For better performance, `namespace eval ...` is usually
[bytecode%|%byte-compiled] when it is given one argument which is a literal
string:

======
proc main {
    namespace eval [info cmdcount] {
        set msg {this script is eligible to be byte-compiled}
        return $msg
    }
}
======


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