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Re: Arrow Syntax is Dumb

  • To: mathgroup at
  • Subject: [mg30729] Re: Arrow Syntax is Dumb
  • From: Jens-Peer Kuska <kuska at>
  • Date: Sat, 8 Sep 2001 02:56:18 -0400 (EDT)
  • Organization: Universitaet Leipzig
  • References: <9n17vd$24n$>
  • Sender: owner-wri-mathgroup at


it is not so dump as it seems.
Because a line can have many more points than only
two but an arrow should not have more than 
a starting and a end point.
But you can simply setup the pattern for 
the form you like with


Arrow[{p1_, p2_}, opts___?OptionQ] := Arrow[p1, p2, opts]
Arrow[l : {{_, _} ..}, opts___?OptionQ] :=
  Arrow[#, opts] & /@ Drop[Transpose[{l, RotateLeft[l]}], -1]


aes wrote:
> Sorry for inflammatory Subject: [mg30729] line . .  but I'd suggest that having
> the syntax
>    Line[ {{x1, y1}, {x2, y2}} ]
> but
>    Arrow[ {x1, y1}, {x2, y2} ]
> is, shall we say,  a "considerably less than optimum" design choice from
> the user's viewpoint.
> I see the point, that an arrow (at this time anyway) has only two
> points, while a line may have multiple points,
> Nonetheless, it seems common sense that an arrow *is* nothing more than
> a two-point line, and therefore it would be a whole lot more consistent
> to use the same syntax.
> A user might for example have some Lines in a graphic pointing from text
> labels to data points, and then learn for the first time about Arrow.
> It would seem obvious to just change those "Lines" to "Arrows" in the
> notebook.
> And, there could be lots of future uses for "broken arrows" -- i.e.,
> multiple-segment arrows, which zig-zag around some obstacle in a graphic
> before reaching their target -- in which case consistency with the Line
> syntax would be even more useful.

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