In Marlin-Na/terser: A Terse Syntax for Function Declaration in R

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  fig.path = "README-"
)

terser

A natural and terse syntax of function declaration in R for people who are interested in shooting yourself in the foot :gun:.

You can use f(x, y) = x + y to define a function f.

library(terser)

f(x, y) = x + y
f(3, 4)

How... ?

Yes! I overwrite the = operator.

If the left hand side is a symbol, it just does normal assignment like the <- operator. If the left hand side is a function call, it defines a function.

Some more examples:

x = 3
x

f(x, y) = x + y
f(2, 3)
identical(f, function(x, y) x + y)

g(x = 231) = log(x)
g()
identical(g, function(x = 231) log(x))

h(a, b = a^2) = a + b
h(1)
h(1, 2)
identical(h, function(a, b = a^2) a + b)

tan2(a) = sin(a)/cos(a)
tan2(pi)

`∑`(...) = sum(...)
`∑`(2, 3, 4)

Warning

The operator = can no longer do assignment for attributes and elements, the following will no longer work. Use <- instead.

names(x) = c("a", "b", "c")
x[[2]] = 32

See also

This package is inspired by a syntax for defining a function in Julia.

julia> f(x, y) = x + y
f (generic function with 1 method)

Marlin-Na/terser documentation built on May 17, 2019, 6:21 p.m.