Special Mathematica Cell to work with R code

Question

I have enjoyed working with R inside Mathematica. But it would be nice If I could have a special R cell. For example, instead of typing

REvaluate["{
      data(iris)
      reg <- lm( Sepal.Length ~ Species, data=iris )
      summary.text <- capture.output(print( summary(reg)) )
   }"]

I would change the cell style to the special R code one and simply type in the code as I would do in a terminal window. Like so:

  data(iris)
  reg <- lm( Sepal.Length ~ Species, data=iris )
  summary.text <- capture.output(print( summary(reg)) )

Is there some way to create such a FrontEnd cell?

In the future I would like Mathematica to have code highlighting and autocompletion for such cells. This would make Mathematica the best environment for working with R.

Answer 1

The following is a style for an R cell, inspired by this answer. You can add this to your stylesheet (change the styles to your liking):

Cell[StyleData["R"],
    CellMargins->{{66, 10}, {5, 10}},
    Evaluatable->True,
    Background->RGBColor[1,1,0.85],
    AutoQuoteCharacters->{},
    CellEvaluationFunction -> (REvaluate["{"<>ToString@#<>"}"]&),
    CellFrameLabels -> {{None,"R"},{None,None}},
    LanguageCategory->"R",
    FormatType->InputForm,
    FontFamily -> "Inconsolata-dz",
    MenuCommandKey->"8"
]

You can now create a new R cell by pressing Cmd8, but you'll have to manually remove the MenuCommandKey setting from the "Code" style before it'll work. Alternately, you can simply press Cmd0 and choose R from the list.

You then use it just like any other input/code cell. Paste your R code into the cell and hit ShiftReturn and it'll evaluate it (assuming RLink has already been called, etc.)

Answer 2

The R code highlighter

There is an undocumented symbol

RLink`Private`rcell

When you type it and press Shift+Enter, you get a syntax-highlighted R code cell based on my real-time syntax highlighter, which is connected to REvaluate and highlights the code as you type. Note that the cell where you type RLink`Private`rcell will be gone, replaced with the new R code cell.

If it is too much typing, you can make an alias like so:

rc := RLink`Private`rcell

and then evaluate rc instead.

Here is a sample screenshot:

Some details

As noted in my answer about the highlighter, it does perform bracket and parentheses matching / highlighting as well. To make it more responsive, I disables re-parsing on all keys except left/right arrows and space bar, so you will have to press one of those to re-render. Normally they are pressed most frequently when working with code, so this should not be very noticable. Also, the cursor may disappear at times, but again, pressing these keys should make it re-appear. The same remark goes to the visibility of block selection.

Note that, as present, rcell does not understand the multi-line code string without curly braces. One way to fix this is to execute this code:

ClearAll[RLink`Private`replR]
RLink`Private`replR[code_String] :=
    REvaluate["{" <> code <> "}"]

Limitations

For Windows, the highlighter works fine. For other platforms, the highlighter was giving me crashes on some Linux flavors and on Mac. But, I got reports for other Linux flavors that it worked fine there. So, ymmv, but you can give it a try.

Apart from problems on specific platforms, the highlighter may have a few glitches. If you find some, I would appreciate if you report them to me.