[Python-Dev] Is implicit underscore assignment buggy?

[Terry Reedy]

"Guido van Rossum" <guido at python.org> wrote in message 
news:ca471dc20606071625y55199a73r6ae369d5c8de4f52 at mail.gmail.com...
> This is by design.
>
> The intent is that as long as you call something that returns no
> value, your last result is not thrown away. IOW _ is the last result
> that wasn't None.
>
> Please don't change this.

What might be improved is the documentation of this, which I could not find 
in a few minutes of searching.  As of current 2.4 docs, the Tutorial, 
Language, and Library manuals all have index pages for identifiers 
beginning with '_' but none contain '_' itself.  (And none have entries for 
'underscore'.)

Language Reference 2.3.2 Reserved classes of identifiers lists all the 
other special identifier classes starting with '_' but not '_' itself.  I 
think this would be a good place for an entry for '_' and its special 
meaning in interactive mode.

Tutorial 2.1.2 Interactive Mode would be another place to mention the 
special use of '_'.

If there is something I missed (that is not indexed), then I missed it.

Terry Jan Reedy