[R] plotmath: unexpected SPECIAL

[Dennis Murphy]

Hi:

>From the plotmath help page:

x %->% y	 x right-arrow y

so this is behaving like a binary operator. There happen to be several
of these in plotmath

On Wed, Jun 22, 2011 at 5:49 PM, Sarah Goslee <sarah.goslee at gmail.com> wrote:
> Interesting. I don't know the explanation, but look at this:
> # works
> plot(1:10, 1:10, xlab=expression(a %->% b))
> # doesn't work
> plot(1:10, 1:10, xlab=expression(%->%))

Because there are no operands. This behavior can be replicated from
the command line:

> 10 %/% 2
[1] 5
> %/%
Error: unexpected SPECIAL in "%/%"

I think this explains the rest of the non-working examples as well,
since you wouldn't do such things with binary operators.

>
> # works
> plot(1:10, 1:10, xlab=expression(paste("something" %->% "else")))
> # doesn't work
> plot(1:10, 1:10, xlab=expression(paste("something", %->%, "else")))
>
> The "doesn't work" examples give the same error you report:
> Error: unexpected SPECIAL in "plot(1:10, 1:10, xlab=expression(%->%"
>
> And then there's:
> # doesn't work, as expected
> plot(1:10, 1:10, xlab=expression(paste("something" phi "else")))

phi is not an operator...

> # works
> plot(1:10, 1:10, xlab=expression(paste("something", phi, "else")))
>
> # works
> plot(1:10, 1:10, xlab=expression(paste("something" %==% "else")))
> # doesn't work
> plot(1:10, 1:10, xlab=expression(paste("something", %==%, "else")))
>
> So it seems that when using an expression element bracketed by percent
> signs, the commas in paste cause an error, even though they are
> otherwise necessary. Hm.
>
> This is on a clean R 2.11 session on linux (I know, but that's the
> latest version in the UNR repository, and I don't use R enough on this
> netbook to install a non-repo version). I can try again tomorrow on an
> up-to-date system.
>
> Sarah
> - Hide quoted text -
>
>
> On Wed, Jun 22, 2011 at 8:10 PM, Bryan Hanson <hanson at depauw.edu> wrote:
>> Hello R Masters and the Rest of Us:
>>
>> The first of these works fine, the 2nd is accepted but too literal (the
>> "%->%" is shown in the plot label and in the wrong position).  The 3rd
>> throws and error due to "unexpected SPECIAL".  Would someone recommend a way
>> to format this?  I want the two phrases connected by a right arrow.
>>
>> TIA, these things always elude me.  Bryan
>
> --
> Sarah Goslee
> http://www.functionaldiversity.org
>
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