Specify different date ranges for \printbibliography in biblatex with biber

Question

I use biblatex-chicago for writing my PhD thesis, and I have only one file for the bibliography. I need to separate my bibliography into primary and secondary sources. From what I understand about the existing solutions on the forum and the documentation, it is only possible to either sort manually each entry with a ‹type› (or keyword), or to make two bib files (one source and one secondary literature).

I was wondering if there was a way to print the bibliography sorting primary sources and secondary sources without going manually in every citation in my bib file as ‹type› or ‹keyword› "source" or "secondary literature". I may be wrong but it doesn't seem that the year of publication is accepted as a key and a value. Isn't there a way to print only entries that are within a specified range of dates?

Answer 1

You can do this via \defbibcheck, but I'd think it rather a fragile/unreliable way of separating primary and secondary sources. What will you do with (e.g.) a 1995 edition of Cicero?

Anyway, the following example is taken straight from the documentation

\defbibcheck{late}{
  \iffieldint{year}
  {\ifnumless{\thefield{year}}{1900}
    {\skipentry}
    {}}
  {\skipentry}
}

This should exclude anything except entries that do have a year and where the year is after 1900. You can fiddle with things like \ifnumgreater or even multiple tests to check keywords and so forth. And of course define a different one for early sources. You then use it with

\printbibliography[check=late]

The other way of doing this would be by using sourcemap to add keywords.