interesting point set by _
> indent line (or interregion if > _) according to major mode
@ add position to `skeleton-positions'
- & do next ELEMENT iff previous moved point
- | do next ELEMENT iff previous didn't move point
+ & do next ELEMENT if previous moved point
+ | do next ELEMENT if previous didn't move point
-num delete num preceding characters (see `skeleton-untabify')
resume: skipped, continue here if quit is signaled
nil skipped