Understanding Biblatex's abbreviations

Question

One of my students has asked me the following question, which I have no idea how to answer.

In the following example, why does one entry contain the abbreviation comm. while the other contains the abbreviation comment.. I'm assuming that both are intended to be abbreviations for 'commentary', but I do not know why Biblatex distinguishes the two cases. (The distinction is clearly deliberate - see below.)

\begin{filecontents}{\jobname.bib}
@incollection{ch-with-comm,
  author        =   {Author, A. N.},
  title         =   {Arduous Anti-Adventures},
  pages         =   {3--4},
  editor        =   {Cracks, Wise and Alec, Smart},
  commentator   =   {Cracks, Wise and Alec, Smart},
  booktitle    =   {Positive Pitfalls},
  publisher     =   {BRU},
  address       =   {Universe},
  year          =   2009}
@incollection{chap-with-comm,
  author        =   {Author, A. N. Other},
  title         =   {Bonkers Boggling Bathrobes},
  pages         =   {39--47},
  editor        =   {Cracks, Wise and Alec, Smart},
  commentator   =   {Cracks, Wise},
  booktitle    =   {Positive Pitfalls},
  publisher     =   {BRU},
  address       =   {Universe},
  year          =   2009}
\end{filecontents}
\documentclass{article}
\usepackage[backend=biber]{biblatex}
\bibliography{\jobname}
\begin{document}
\Autocite{ch-with-comm,chap-with-comm}
\printbibliography
\end{document}

In english.lbx, we have

  withcommentator  = {{with a commentary by}{with a comment\adddot\ by}},

but this is the only place in which the abbreviation is comment\adddot rather than comm\adddot.

Looking at the way Biblatex handles string definitions, I must admit that it seems to be a recipe for inconsistency, since nothing is reused. That is, I would have expected a single definition for, say, each of \commentary@full and \commentary@abbrv, which would then be reused when defining subsequent strings requiring the same word. This would make it easy for users to override a default, if desired, and help to ensure consistency and ease of maintenance. But, instead, the same basic definition is basically repeated over and over, will all the concomitant room for error.

But, very clearly, Biblatex is a thoroughly considered and carefully designed package. So I find it difficult to believe that there is no reason for either the system, in general, or the apparent discrepancy, in particular.

Could somebody enlighten us?

EDIT

Note that, in other cases, comm\adddot is used regardless of whether the long form is commented or commentary. For example,

translatorscoaf  = {{translation, commentary\finalandcomma\ and afterword}%
                  {trans., comm\adddot\finalandcomma\ and afterw\adddot}}

where 'commentary' is abbreviated as comm\adddot, and

byeditorco       = {{edited and commented by}%
                  {ed\adddotspace and comm\adddot\ by}},

where 'commented' is abbreviated by comm\adddot.

Answer 1

The commentator field was introduced in version 0.5 of biblatex. I could obtain version 0.8, and in that version the commentator/commentary-related strings were already as they are today.

Unfortunately, we can't ask Philipp Lehmann why things are the way they are. I think it is fair to assume that this was an oversight. Since the string is among the more rarely used, I think it is not at all unlikely that an inconsistency like this remained undetected for quite some time.

Either PL wanted to abbreviate 'commentator' and 'commentary' differently, and that was forgotten about when the combined bibstrings were written; or he didn't mean to do so and the comment\adddot was an oversight and not intentional.

There are a few other inconsistencies in english.lbx with respect to the punctuation commands used. I assume they arose because the file grew organically and was not written in one go.

It is true that the .lbxs in their current form feature quite bit of redundancy, especially when it comes to the 'combined' bibstrings. Introducing another layer of macros would make things more complicated and was probably not seen as necessary when things started out. When things grow it is not always possible to foresee what is going to be needed.