* TODO Define all possibly needed variants of each concept.
- The different axis include:
1. "typeset as" (full-form/short-form)
2. "inflection" (singular/plural)
3. "sort as"
- All entries should be typeset identically in the text and in the
index.
- Both of the following example entries in the *CONCEPTS* section
('|' represents the left-most border)
|LaTeX@{\LaTeX} cat
|LaTeX cat@{\LaTeX cat}
should result in the following attributes being defined for an
IndexEntry instance: