The goal of typos is to provide a flexible warning when commonly mis-typed functions are called. Functions with typing errors will still be evaluated and a warning will be output. It also provides the user with a convenient function to define their own typos.

## Installation

You can install the development version of typos from GitHub with:

# install.packages("devtools")
devtools::install_github("MyKo101/typos")

## Example

For example, without typos installed, mistyping the functions names() as nameS() will throw an error.

nameS(mtcars)
#> Warning: Typo of "names()" detected in "nameS()"
#>  [1] "mpg"  "cyl"  "disp" "hp"   "drat" "wt"   "qsec" "vs"   "am"   "gear" "carb"

But, with typos, the function is still evaluated, and rather than an Error, a Warning is produced.

library(typos)
nameS(mtcars)
#> Warning: Typo of "names()" detected in "nameS()"
#>  [1] "mpg"  "cyl"  "disp" "hp"   "drat" "wt"   "qsec" "vs"   "am"   "gear" "carb"

## Generating typos

The key to typo is the .typo() function. To generate a typo, we use the following syntax:

<incorrect spelling> <- .typo(<correct spelling>)

For example, the above nameS typo is generated with

nameS <- .typo(names)

## Wrapping

The way .typo() works is to generate a wrapper function around the correctly spelled function. This wrapper function sends a warning to the user, but still evaluates the “proper” function.

The wrapper function, nameS looks like this:

nameS
#> function(...)
#> {
#>  requireNamespace("base",quietly=T)
#>  .call <- match.call()
#>  .incorrect_call <- as_name(.call[[1]])
#>  .call[[1]] <- quote(names)
#>  eval_tidy(.call,env=rlang::caller_env())
#> }
#> <environment: namespace:typos>

Notice that all the arguments passed to nameS(...) are forwarded on to names(...)

## Other packages

As well as the correctly spelled function, the .typo() function can take a .package argument (this will always be the second unnamed argument, so code can be neater). By default, this will be the base package, but any other package will need to be specified (this includes default packages like stats).

Rnorm <- .typo(rnorm,stats)

Within the wrapper function, this changes two things. The argument passed to requireNamespace() will match this package, as will the “proper” function call

Rnorm
#> function(...)
#> {
#>  requireNamespace("stats",quietly=T)
#>  .call <- match.call()
#>  .incorrect_call <- as_name(.call[[1]])
#>  .call[[1]] <- quote(rnorm)
#> <environment: 0x00000242b5f8fa40>
Caution should be used if the misspelled version of your function already exists as a function in it’s own right. The .typo() will overwrite the other “correct” function with the new typo function. For this reason, it is recommended that typos be the first package loaded to ensure functions loaded in other packages can overwrite the Exported typos provided here.