From: hadley wickham <h.wickham@...>
Date: 2006-10-16T22:37:16+09:00
Subject: Re: [ANN] RSRuby 0.4

> RSRuby allows the user to embed a full R interpreter into a Ruby
> script. This allows the script to call any R function and convert the
> result back into Ruby. From the R website: 'R is a free software
> environment for statistical computing and graphics.'. Running a
> students t-test (or any other R function) is as simple as:
>
>    require 'rsruby'
>    r=RSRuby.instance            #Create R interpreter
>    ttest = r.t_test([1,2,3])            #Convert [1,2,3] to R. Run t.test
> function and convert result back to Ruby
>    puts ttest['p.value']                #Prints out p.value statistic from the
> ttest object

That looks really great.

However, I have a couple of points about the conversion:

 - R Logicals (true/false) <=> Ruby true/false
 - R Integers <=> Ruby Fixnum/Bignum
 - R Numeric  <=> Ruby Float
 - R String   <=> Ruby String

These guys are all vectors in R - do you mean vectors of length one
are converted to the corresponding Ruby primitives?  (Also,
confusingly, in R a string is called a character vector of length 1)

 - R Vector   <=> Ruby Array (homogeneous)

There isn't really a vector "class" in R, independent of the things
listed above.

 - R List     <=> Ruby Hash

I think a better mapping would be to Ara's ArrayFields class.  Lists
in R can be accessed by name or by position.

Regards,

Hadley