Introduce `history_since_<id>` value expansion

The `history_since_<id>` value expansion allows incremental parsing of a
buffer's history.

    declare-option int my_last_history_id
    define-command my-process-history ...

    # process the initial buffer history
    my-process-history %val{bufname} 0 %val{history}
    set-option buffer my_last_history_id 0

    # only process new history changes on idle
    hook buffer NormalIdle %{
        evaluate-commands %exp{
            my-process-history \
                %%val{bufname} \
                %%opt{my_last_history_id} \
                %%val{history_since_%opt{my_last_history_id}}
        }
        set-option buffer my_last_history_id %val{history_id}
    }

1 files changed, 1 insertions, 1 deletions

diff --git a/src/buffer_utils.hh b/src/buffer_utils.hh
index 96e89743..f677c34e 100644
--- a/src/buffer_utils.hh
+++ b/src/buffer_utils.hh
@@ -97,7 +97,7 @@ void write_buffer_to_backup_file(Buffer& buffer);
 
 void write_to_debug_buffer(StringView str);
 
-Vector<String> history_as_strings(const Vector<Buffer::HistoryNode>& history);
+Vector<String> history_as_strings(ConstArrayView<Buffer::HistoryNode> history);
 Vector<String> undo_group_as_strings(const Buffer::UndoGroup& undo_group);
 
 String generate_buffer_name(StringView pattern);