This is one of the items from "#Q397: List of Bugs from #nethack" sent
in Janurary by <email deleted> and containing a list
of things collected from the IRC channel associated with nethack.alt.org's
public server. Moving diagonally between segments of a worm tail is
conceptually passing right through the worm's body. This patch prevents
moving in such a fashion for both the hero and monsters (it's still
possible to fight in that position though). It only applies when the two
tail segments are consecutive.
|...... In the diagram here, where tail segments are represented by
|.w1?.. digits indicating relative sequence number, the @ can still
|..@2.. move between segments 2 and 5 to reach !, but can no longer
|.65!3. move between 1 and 2 to reach ?. [However, if there is a
|...4.. monster at the ? spot, it can still hit @ and vice versa.]
Missiles and wand zaps still pass through such diagonals without
noticing or affecting the worm. I'm not sure whether this ought to be
extended to change that--it might get pretty messy since it would need
to be considered during monsters' targetting as well as during the path
traversal itself.
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