Multi-level counter pitfalls (counters package)

[Omikhleia]

(For the record, sharpening counters was evoked in #455)

When working on my book class (and a pending article class to go with it), I quickly hacked the multilevel counters. Since I am refactoring it for 0.14, it's perhaps time for me to report my findings / issues. (I can make a PR with my changes so far, just mentioning the main points below, some could be questionable.)

• formatMultilevelCounter() issues

  • It behaves quite badly if the (optional) level parameter is greater than the current level (robustness)
  • An option for skipping leading zeroes would really be handy for classes that would accept, e.g. unnumbered chapters to have sections naturally starting at 1, not 0.1 (and so on).
  • BTW, I would question the "minlevel" option, what's the use case for it? Having a counter "1.2.3.4", is one really expecting a use case for formatting, say, "2.3"? For the sake of simplicity over over-design, I'd suggest removing it. Bah, could be kept anyway. Just weird maybe.

• \set-multilevel-counter missing

  • For single-counters, we have \set-counter, so it sounds logical having it here too.
  • The class may need to reset sectioning counters to some level (e.g. entering an appendix, resetting chapter level to 1, with alpha display, etc.)

• \show-multilevel-counter

  • It claims "optionally displaying it with the <display> format", but this is really confusing as:
    • These are multilevel counters where all levels may have different display format
    • The option currently acts on the current level, without regards for the requested level.
    • The option (as for the \show-counter too) does not only use that display for showing, it also alters it (so this is still changed afterwards).