[Rd] possible improvement to ?with examples

[Ben Bolker]

A querent on StackOverflow asked about the with() function

http://stackoverflow.com/questions/42283479/why-when-to-use-with-function#42283479

and asked about the example in ?with

library(MASS)
     with(anorexia, {
         anorex.1 <- glm(Postwt ~ Prewt + Treat + offset(Prewt),
                         family = gaussian)
         summary(anorex.1)
     })

which saves little or no typing relative to

   anorex.1 <- glm(Postwt ~ Prewt + Treat + offset(Prewt),
                         family = gaussian, data=anorexia)

(I would argue that the latter is better practice anyway).

  Could we have something more sensible like

   with(mtcars,mpg[cyl==8 & disp>350])

?  (It could be contrasted directly with

mtcars$mpg[mtcars$cyl==8 & mtcars$disp>350]

)

I'm happy to submit a bug report/patch if that seems appropriate.

  cheers
    Ben Bolker