Corner Cases

John Mount

2018-04-03

wrapr::let() is designed to get several important corner cases correct: including substitutions that are disjoint from the expression and symbol swaps.

library("wrapr")

X <- 1
Y <- 2

let(
 c(),
  debugPrint = TRUE,
  X + Y
)

## list()
## X + Y

## [1] 3

let(
 c(),
  debugPrint = TRUE,
  subsMethod = 'langsubs',
  X + Y
)

## list()
## X + Y

## [1] 3

let(
 c(),
  debugPrint = TRUE,
  subsMethod = 'stringsubs',
  X + Y
)

## list()
## X + Y

## [1] 3

let(
 c(),
  debugPrint = TRUE,
  subsMethod = 'subsubs',
  X + Y
)

## list()
## X + Y

## [1] 3

library("wrapr")

X <- 1
Y <- 2

let(
  c(X='Y', Y='X'),
  debugPrint = TRUE,
  X + Y
)

## $X
## [1] "Y"
## 
## $Y
## [1] "X"
## 
## Y + X

## [1] 3

let(
  c(X='Y', Y='X'),
  debugPrint = TRUE,
  subsMethod = 'langsubs',
  X + Y
)

## $X
## [1] "Y"
## 
## $Y
## [1] "X"
## 
## Y + X

## [1] 3

let(
  c(X='Y', Y='X'),
  debugPrint = TRUE,
  subsMethod = 'stringsubs',
  X + Y
)

## $X
## [1] "Y"
## 
## $Y
## [1] "X"
## 
## expression(Y + X)

## [1] 3

let(
  c(X='Y', Y='X'),
  debugPrint = TRUE,
  subsMethod = 'subsubs',
  X + Y
)

## $X
## [1] "Y"
## 
## $Y
## [1] "X"
## 
## Y + X

## [1] 3