Test out let with LM

let-lm.R

## Tests based on https://mailund.dk/posts/scoping-rules-and-nse/
# rm(list=ls())
if(length(ls())) message("you have variables defined in the environment")

library(wrapr)
lm_prop2a <- function(x, y, d, prop, eval) {
    let(c(x = x, y = y, prop = prop, d=d),
        summary(lm(y ~ x, data = d))$prop,
        eval = eval, envir=parent.frame())
}
indirect2a <- function(xx, yy, eval) {
    d <- data.frame(x = xx, y = yy)
    lm_prop2a("x", "y", "d", "residuals", eval = eval)
}

## First set of tests

set.seed(42)
d1 <- data.frame(x = rnorm(5), y = rnorm(5))
d2 <- data.frame(a = rnorm(5), b = rnorm(5))
xx <- rnorm(5)

(res <- lm_prop2a("x", "y", "d1", "residuals", eval = TRUE))
stopifnot(identical(res, summary(lm(y ~ x, d1))$residuals))

(res <- lm_prop2a("xx", "y", "d1", "residuals", eval = TRUE))
stopifnot(identical(res, summary(lm(y ~ xx, d1))$residuals))

(res <- lm_prop2a("a", "b", "d2", "residuals", eval = TRUE))
stopifnot(identical(res, summary(lm(b ~ a, d2))$residuals))

(res <- lm_prop2a("xx", "b", "d2", "residuals", eval = TRUE))
stopifnot(identical(res, summary(lm(b ~ xx, d2))$residuals))

## Second set

x <- a <- xx

(res <- lm_prop2a("a", "y", "d1", "residuals", eval = TRUE))
stopifnot(identical(res, summary(lm(y ~ a, d1))$residuals))

(res <- lm_prop2a("x", "b", "d2", "residuals", eval = TRUE))
stopifnot(identical(res, summary(lm(b ~ x, d2))$residuals))

## Last set

aa <- rnorm(5) ; bb <- rnorm(5)

(res <- indirect2a(aa, bb, eval = TRUE))
stopifnot(identical(res, summary(lm(bb ~ aa))$residuals))