typewriter

The goal of typewriter is to add type safety to your R code.

Installation

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

# install.packages("devtools")
devtools::install_github("eoda-dev/typewriter")

Examples

library(typewriter)

# Functions
f <- function(a = "integer", b = "integer:1") {
  check_args()
  a + b
}

f(5L, 3L)
#> [1] 8

try(f(5L, c(3L, 4L)))
#> Error in base_model(fields)(.x = func_env) : Type check(s) failed
#> ---
#> Type check failed for 'b'
#> value:  int [1:2] 3 4
#> type: integer
#> class: integer
#> length: 2
#> value of 'b' must be of type integer(1)

# Data frames
df <- data.frame(
  id = 1:3,
  letter = letters[1:3]
)

my_model <- base_model(
  id = "integer",
  letter = "character"
)

model_validate(df, my_model)
#>   id letter
#> 1  1      a
#> 2  2      b
#> 3  3      c

df$id <- as.double(df$id)
try(model_validate(df, my_model))
#> Error in model_fn(.x = obj) : Type check(s) failed
#> ---
#> Type check failed for 'id'
#> value:  num [1:3] 1 2 3
#> type: double
#> class: numeric
#> length: 3
#> value of 'id' must be of type integer

# Typed structs
my_type <- typed_struct(
  a = "integer",
  b = "integer"
)

(mt <- my_type(a = 2L, b = 4L))
#> $a
#> [1] 2
#> 
#> $b
#> [1] 4

class(mt)
#> [1] "list"       "typewriter" "my_type"

try(mt$a <- 10.5)
#> Error in check_assignment(x, name, value) : Type check failed.
#> value of 'a' must be of type integer

try(my_type(a = 2L, b = 4.5))
#> Error in my_type(a = 2L, b = 4.5) : Type check(s) failed
#> ---
#> Type check failed for 'b'
#> value:  num 4.5
#> type: double
#> class: numeric
#> length: 1
#> value of 'b' must be of type integer