editor

Experimental!

{editor} can be used to edit scripts programmatically.

We propose the functions

• edit_insert(path, code, before = NULL, after = NULL, style = TRUE)
• edit_replace(path, code, selection, style = TRUE)
• edit_remove(path, selection, style = TRUE)

The position where to insert/replace/remove code is fed to the selection, before or after args.

We can provide line numbers there but also by tailor made tidy selection helpers:

• line_matches(code, n = NULL) to match a line’s code
• expr_defines(var, n = NULL) to match a variable definition
• expr_calls(fun, n = NULL) to match a function call

By default the matches are exact (ignoring leading and trailing white spaces on both sides), but we can use {stringr}’s modifiers like stringr::regex() for more flexibility.

To match a definition or call inside a function definition we can use :

• in_function(fun, selection, n = NULL)

So for example we’ll do

edit_insert("my_script.R", 'print("hello")', after = in_function("fun1", expr_defines("x")))`

And we’ll have a print("hello") statement inserted in the fun1()’s definition right after x is defined.

Installation

Install with:

remotes::install_github("moodymudskipper/editor")

Example

library(editor)
code <- '
# some
# comment
with_equal = c(
  1,
  2
)

with_arrow <- c(
  3,
  4
)

this <- {
  "this"
}

fun1 <- function() {
  hello <- 1
  world <- 2
  fun2 <- function() {
    hi <- 2
    again <- 3
  }
}

a(1)

ab(2)

abc(3)
'

file <- tempfile()
writeLines(code, file)
  
edit_remove(file, 2:3) # remove leading comment
edit_remove(file, expr_defines("with_equal"))
edit_remove(file, expr_defines("with_arrow"))
edit_replace(file, toupper, expr_calls(regex("a"), 3))
edit_replace(file, toupper, expr_calls("a"))
edit_remove(file, in_function("fun1", expr_defines("world")))
edit_remove(file, in_function("fun1", in_function("fun2", expr_defines("again"))))
edit_insert(file, 'print("hello")', after = expr_defines("this"))
edit_insert(file, ~paste("#", .x), before = expr_defines("this"))
edit_replace(file, toupper, line_matches('"this"'))
  
styler::style_text(readLines(file))
#> # this <- {
#> #   "this"
#> # }
#> this <- {
#>   "THIS"
#> }
#> print("hello")
#> 
#> fun1 <- function() {
#>   hello <- 1
#>   fun2 <- function() {
#>     hi <- 2
#>   }
#> }
#> 
#> A(1)
#> 
#> ab(2)
#> 
#> ABC(3)