ticked arrowheads in xy-pic and diagxy

ticked arrowheads in xy-pic and diagxy

[Michael Barr]

A month or two ago, Micah McCurdy wrote to ask me if it was possible to
make an arrow with a tick in the middle (that is ----+---->) and I said I
didn't know how to do that and suggested he ask Ross Moore.  Ross told him
that xy-pic didn't have that capacity.  Well, Micah discovered that it
did.  Here are some samples, using diagxy, but that is just a front end to
xy-pic.

  $$\bfig
\node a(0,0)[A]
\node b(300,400)[B]
\arrow/@{>}|-*@{>}/[a`b;f]
  \efig$$


  $$\bfig
  \ptriangle/>`>`@{>}|-@{|}/[A`B`C;f`g`h]
  \efig$$



  $$\bfig
  \morphism/@{>}|-@{+}/<700,0>[ABCDE`F;h]
  \efig$$


  $$\bfig
  \morphism/@{>}|-*@{|}/<700,0>[ABCDE`F;h]
  \efig$$

As far as I can tell, the * between the - and the @ has no effect.  The
one limitation is that what goes inside the -@{ } must be a \dir.  This is
a limitation for me, since I cannot figure out the syntax of \newdir.  For
this to work, it clearly has to be something that tex can rotate.

Michael