README.md

In ngr-t/r-bindedEval: Evaluation with name binding

bindedEval

This is a R package which provides let() and where() functions which evaluates expressions with name binding. They mimicks Haskell's let formula and where clause.

Installation

install_github("ngr-t/r-bindedEval")

Usage

library(magrittr)
library(bindedEval)

z <- let(x = 1, y = 2, .in = x + y)
# We can't access x and y from the outside of `let()`

velocity_let <- function (x1, x2, t1, t2) let(
  dx = x2 - x1,
  dt = t2 - t1,
  .in = dx / dt)
velocity_let(80, 90, 0, 0.5)

velocity_where <- (function (x1, x2, t1, t2) {
  dx / dt
}) %>% where(
  dx = x2 - x1,
  dt = t2 - t1)
velocity_where(80, 90, 0, 0.5)

The all variables binded by let() and where() are locked, so we can't overwrite them.

ngr-t/r-bindedEval documentation built on May 23, 2019, 4:43 p.m.