[Python-Dev] Re: doctest improvements

[Terry Reedy]

"Edward Loper" <edloper at gradient.cis.upenn.edu> wrote in message
news:40BBF4C4.2090204 at gradient.cis.upenn.edu...
> Tim Peters wrote:
> > That's more what I had in mind, but if the marker is changed to
something
> > wordy instead of "a magic character", I don't think the dedent trick is
of
> > much value anymore:
> >
> >      r"""
> >      A different marker:
> >
> >              >>> print 'a\n\nb'
> >              a
> >              <blank line>
> >              b
> >      """
> >
> > Then when the expected output is (exactly) "<blank line>", doctest
would
> > accept "<blank line>", or a line with nothing other than whitespace, as
a
> > match.  I can't get upset by that bit of ambiguity.
>
> I had ruled this out because I assumed that any change I made had to
> maintain backward compatibility.  But if this (minor) incompatibility is
> acceptable, then let me know and I'll write up a patch to implement it.

To me as a potential user, '<blank line>' is the uniquely obvious marker
for a blank line.  The ambiguity is fine; having it uniquely not match
itself and therefore needing a special case escape mechanism would be
worse.  I think the explanation "<blank line> matches a blank line as well
as itself" might be sufficient.

Terry J. Reedy