grapes

In some computing subcultures, the term "grapes" refers to the percent sign, which R uses to name binary operators such as %*%. Here, grapes is an R package that turns arbitrary functions into binary operators. As with the magrittr pipe, this allows you to avoid cumbersome parentheses in your code.

library(grapes)
grow(rbind, c, from = "base") # Use `from` to specify a package or environment to search.
bunch()
nrow(sleep) 
longer = sleep %rbind% sleep %rbind% sleep
nrow(longer)
1 %rbind% 2 %c% 3

In your workspace, you can define your own functions for your operators. That way, there is no need to set the from argument to tell grow() where to look.

myop <- function(x, y){
  1/x + 1/y
}
grow(myop)
2 %myop% 3

Use bunch() and functions() to list the available operators and non-operator functions.

bunch()
functions()

Operators are left-associative!

2 %myop% 3 %myop% 4
(2 %myop% 3) %myop% 4
2 %myop% (3 %myop% 4)

You can even turn all available functions from a package or environment into operators. But be warned: there is no guarantee that these operators will actually work.

functions("knitr")
bunch("knitr")
grow(from = "knitr")
bunch()
`%purl%`

Advanced users can supply environments to the from and to arguments. This affords more control over where the functions come from and where the operators get assigned.

to_env = new.env()
from_env = new.env()
from_env$nextop = function(a, b, extra = 3){
  sqrt(a^2 + b^2) + extra
}
assign_operator = function(){
  grow(nextop, from = from_env, to = to_env)
}
assign_operator()
# 1 %nextop% 2 # throws an error since %nextop% is not defined in your workspace
eval(parse(text = "1 %nextop% 2"), envir = to_env)
bunch(from_env)
functions(from_env)
bunch(to_env)
functions(to_env)


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grapes documentation built on May 29, 2017, 8:39 p.m.