
In Noweb, chunk names are in the same scope if the files in which the
chunks appear are used on the same command line.
Thus, the normal rule is one Noweb file per command line, and
therefore each file is its own scope.
<p>
You want to have chunks in the same scope for purposes of tangling,
but not to weave files together.
If you want files a.nw and b.nw in separate scopes, the situation is
hopeless, because ``being in the same scope'' has to be a transitive
property, and if a.nw and b.nw are both in the sa