The Definitive ANTLR 4 Reference, 2nd Edition

Parsing R

R is an expressive domain-specific programming language for describing statistical problems. For example, it’s easy to create vectors, apply functions to them, and filter them (shown here using the R interactive shell).

 x <- seq(1,10,.5)     # x = 1, 1.5, 2, 2.5, 3, 3.5, ..., 10
 y <- 1:5              # y = 1, 2, 3, 4, 5
 z <- c(9,6,2,10,-4)   # z = 9, 6, 2, 10, -4
 y + z                 # add two vectors
[1] 10  8  5 14  1     # result is 1-dimensional vector
 z[z<5]                # all elements in z < 5
[1]  2 -4
 mean(z)               # compute the mean of vector z
[1] 4.6
 zero <- function() { return(0) }
 zero()
[1] 0

R is a medium-sized but complicated programming language, and most or all of us have a handicap: we don’t know R. That means we ...