Brethern, perlman debug sez, concerning the 'watch expression':
w expr
Add a global watch-expression. We hope you know what one of these is, because they're supposed to be obvious.
Alas, I don't understand. I'm not even using it right when I try to watch a single variable.
 w $negatePrefix

[download]
But what I really want to do is to watch a particular place within a HoH: 
 w $onto{'PROBLEM'}{'mappings'}

[download]
Can some one give me a more full example of how to use this powerful feature?

throop

In reply to Alas, watch-expression not obvious to this one by throop

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