Parse out the optional value objects.

src/parser/affiliated_keyword.rs

@@ -1,7 +1,18 @@
 use std::collections::BTreeMap;
 
+use nom::bytes::complete::tag;
+use nom::bytes::complete::take_until;
+use nom::character::complete::anychar;
 use nom::combinator::all_consuming;
+use nom::combinator::eof;
+use nom::combinator::map;
+use nom::combinator::map_parser;
+use nom::combinator::opt;
+use nom::combinator::peek;
+use nom::combinator::recognize;
 use nom::multi::many0;
+use nom::multi::many_till;
+use nom::sequence::tuple;
 
 use super::object_parser::standard_set_object;
 use crate::context::parser_with_context;
@@ -45,6 +56,23 @@ pub(crate) fn parse_affiliated_keywords<'g, 's>(
             let initial_context = ContextElement::document_context();
             let initial_context = Context::new(global_settings, List::new(&initial_context));
 
+            let (_remaining, optional_objects) = opt(all_consuming(map(
+                tuple((
+                    take_until("["),
+                    tag("["),
+                    map_parser(
+                        recognize(many_till(anychar, peek(tuple((tag("]"), eof))))),
+                        all_consuming(many0(parser_with_context!(standard_set_object)(
+                            &initial_context,
+                        ))),
+                    ),
+                    tag("]"),
+                    eof,
+                )),
+                |(_, _, objects, _, _)| objects,
+            )))(kw.key.into())
+            .expect("Object parser should always succeed.");
+
             // TODO: This should be omitting footnote references
             let (_remaining, objects) = all_consuming(many0(parser_with_context!(
                 standard_set_object
@@ -55,7 +83,7 @@ pub(crate) fn parse_affiliated_keywords<'g, 's>(
             });
             match list_of_lists {
                 AffiliatedKeywordValue::ListOfListsOfObjects(list_of_lists) => {
-                    list_of_lists.push(objects);
+                    list_of_lists.push((optional_objects, objects));
                 }
                 _ => panic!("Invalid AffiliatedKeywordValue type."),
             }

src/types/affiliated_keyword.rs

@@ -6,7 +6,7 @@ use super::Object;
 pub enum AffiliatedKeywordValue<'s> {
     SingleString(&'s str),
     ListOfStrings(Vec<&'s str>),
-    ListOfListsOfObjects(Vec<Vec<Object<'s>>>),
+    ListOfListsOfObjects(Vec<(Option<Vec<Object<'s>>>, Vec<Object<'s>>)>),
 }
 
 #[derive(Debug)]