Some time ago, Alan Munn asked and lockstep eloquently answered a question about removing parentheses from biblatex authoryear style references. Unfortunately, lockstep's solution injects an unwanted \addperiod\space into "dash" references. For example, given Author, A. cited twice:
\documentclass{article}
\usepackage[style=authoryear]{biblatex}
\usepackage{xpatch}
\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@misc{A01,author={Author, A.},year={2001},title={Alpha}}
@misc{A02,author={Author, A.},year={2001},title={Beta}}
\end{filecontents}
\addbibresource{\jobname.bib}
\nocite{*}
\begin{document}
\printbibliography
\xpatchbibmacro{date+extrayear}{%
\printtext[parens]%
}{%
\addperiod\space%
\printtext%
}{}{}
\printbibliography
\end{document}
we get:

I've tried building a solution using constructs like \usebibmacro{bbx:dashcheck} without success. How, then, based on lockstep's nice xpatch-based approach, can I conditionally include \addperiod\space only in the case of "non-dash" references?

\addperiod\space%and should work. – Marco Daniel Aug 18 '12 at 07:08\addperiod\spaceis required after theauthorfield in normal (non-repeated author, "non-dash") cases. To see this more clearly, change theauthor=field from{Author, A.}to, say,{Author, Anne}. In which case, we want output to look likeAuthor, Anne. 2001aand-- 2001b. Commenting out the\addperiod\spaceproducesAuthor, Anne 2001a. The question is, how can we conditionally remove the period in the repeated author ("dash") case? – Nikki Aug 18 '12 at 07:53