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, ...