biblatex \printfield prints nothing

Question

Consider the following example:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{csquotes}
\usepackage[american]{babel}
\usepackage[backend=biber]{biblatex}


\DeclareBibliographyDriver{unpublished}{%
  \printtext{%
    \printfield{location}\addcomma\space%
    \printfield{year}\addcomma\space%
    \printfield{month}\addcomma\space%
    \printfield{day}}%
}

\addbibresource{my.bib}


\begin{document}

\fullcite{something}

\end{document}

and the respective bib file:

@unpublished{something,
  author       = {Me C. and You K.},
  title        = {Some Awesome Work},
  eventtitle   = {Workshop on Awesome Stuff},
  location     = {Some County in the U.S.},
  year         = {2018},
  month        = {9},
  day          = {7},
  howpublished = {http://www.someurl.com}
}

Compiling the above gives ", 2018, Sept.,".

Indeed the field day is not in the list of available fields given on page 12 of the biblatex manual. However, location is the list of optional fields, and is still not showing.

Are there any rules that govern this behavior, or is this a bug? Moreover, how can I display fields such as day above?

I am using the latest update of the 2017 mactex distribution.

Answer 1

There are two issues at hand here.

As explained in Unable to Call "Publisher" or "Location" in Biblatex and adding location field on biblatex entry you actually need

\printlist{location}

instead of \printfield{location}. biblatex's fields actually come in three flavours (i) field, (ii) list and (iii) name list and you have to use the right command (\printfield, \printlist and \printnames respectively) for each flavour.

The day issue is two-fold. day is not a valid input field. While year and month are retained for backwards compatibility, day is not. So if you want day-precision dates, you must use the date field in the .bib file

date = {2018-09-07},

instead of year = {2018}, month = {9}, day = {7} (which is wrong and will only come out with a year+month date, day is explicitly ignored).

But ideally you should also not use \printfield{month} or \printfield{day} (I would also argue that one should avoid \printfield{year} as well, but there may be legitimate uses for that), instead you should try to use \printdate which will print the date in the correct date format for the active localisation.

When you write your own bibliography drivers you should also look into using biblatex's punctuation tracker. §4.11.7 Using the Punctuation Tracker of the biblatex manual would be the obvious place to start. Normally you will want to wrap commands like \addcomma\space into a \setunit when they are used in a driver.

In the MWE the outer \printtext does nothing useful, so I would remove it, but that can be different in your actual document.