Multiple \DeclareSortExclusion clear each other out about biblatex

[josephwright]

I wonder what is 'expected' here: I'd say one 'declare' overwrites another, as there is no 'undeclare'.

[simifilm]

But it wouldn't make sense not to be able to define different exclusions. If they overwrite each other you're not able, for example, to exclude 'editor' for one document type and 'author' for another one.

[aboruvka]

Based on the code, this is the intended behaviour - a declaration defines an entrytype-specific control sequence that later expands to a complete sortexclusion clause in the bcf (control) file. Multiple clauses such as

    <bcf:sortexclusion type="collection">
      <bcf:exclusion>author</bcf:exclusion>
      <bcf:exclusion>editor</bcf:exclusion>
      <bcf:exclusion>sortname</bcf:exclusion>
      <bcf:exclusion>translator</bcf:exclusion>
    </bcf:sortexclusion>
    <bcf:sortexclusion type="collection">
      <bcf:exclusion>maintitle</bcf:exclusion>
    </bcf:sortexclusion>

won't work as the last one overrides the first. So you'll have to track the excluded fields in \blx@sortexlude (sic) - the internal command called by \DeclareSortExclusion.

\def\blx@sortexlude#1#2{%
  \begingroup
  \ifblank{#1}
    {\global\csundef{blx@bcf@exclude@#2}}
    {\let\blx@tempa\@empty
     \forcsvlist\blx@sortexlude@i{#1}%
     \csxappto{blx@bcf@excludelist@#2}{\blx@tempa}%
     \csxdef{blx@bcf@exclude@#2}{%
       \blx@xml@sortexclude{#2}{\csuse{blx@bcf@excludelist@#2}}}}
  \endgroup}

I'm not convinced this change is needed. Can you clarify your last comment, Simon? I don't quite follow the motivation.

[simifilm]

The motivation is simple – different kind of exclusions.

Let's say I want 'maintitle' excluded for 'collection' and 'incollection', and 'author' and 'editor' for both 'movie' and collection'. How am I supposed to achieve this, if I can't define multiple exclusions? I need something like this to do that:

\DeclareSortExclusion{movie, collection}{author,editor}
\DeclareSortExclusion{incollection, collection}{maintitle}

[aboruvka]

Why not use the following?

\DeclareSortExclusion{collection}{author,editor,maintitle}
\DeclareSortExclusion{movie}{author,editor}
\DeclareSortExclusion{inollection}{maintitle}

[simifilm]

Ah, so this does work. I didn't understand that you can have different exclusions, but not for the same document type.