Linter for space needed after right parenthesis of function symbol formals

[renkun-ken]

Just notice that there seems to be no linter that complains about the following code

function(x)x + 1

where a space is needed between function(x) and x + 1.

[kpagacz]

I don't know if there is any contribution guideline for lintr, therefore I am just going to ask - is it alright if I start working on this?

Do you think it should be a new linter or be a part of an already existing linter?

[renkun-ken]

The following linters might be related to this issue, but they are quite unique on their own.

$ <text>:List of 8
  ..$ filename     : chr "<text>"
  ..$ line_number  : int 1
  ..$ column_number: int 15
  ..$ type         : chr "style"
  ..$ message      : chr "Remove spaces before the left parenthesis in a function call."
  ..$ line         : Named chr "f <- function (x){x + 1}"
  .. ..- attr(*, "names")= chr "1"
  ..$ ranges       : NULL
  ..$ linter       : chr "function_left_parentheses_linter"
  ..- attr(*, "class")= chr "lint"
 $ <text>:List of 8
  ..$ filename     : chr "<text>"
  ..$ line_number  : int 1
  ..$ column_number: int 18
  ..$ type         : chr "style"
  ..$ message      : chr "Opening curly braces should never go on their own line and should always be followed by a new line."
  ..$ line         : Named chr "f <- function (x){x + 1}"
  .. ..- attr(*, "names")= chr "1"
  ..$ ranges       : NULL
  ..$ linter       : chr "open_curly_linter"
  ..- attr(*, "class")= chr "lint"
 $ <text>:List of 8
  ..$ filename     : chr "<text>"
  ..$ line_number  : int 1
  ..$ column_number: int 18
  ..$ type         : chr "style"
  ..$ message      : chr "There should be a space between right parenthesis and an opening curly brace."
  ..$ line         : chr "f <- function (x){x + 1}"
  ..$ ranges       :List of 1
  .. ..$ : num [1:2] 18 18
  ..$ linter       : chr "paren_brace_linter"
  ..- attr(*, "class")= chr "lint"
 $ <text>:List of 8
  ..$ filename     : chr "<text>"
  ..$ line_number  : int 1
  ..$ column_number: int 24
  ..$ type         : chr "style"
  ..$ message      : chr "Closing curly-braces should always be on their own line, unless they are followed by an else."
  ..$ line         : Named chr "f <- function (x){x + 1}"
  .. ..- attr(*, "names")= chr "1"
  ..$ ranges       : NULL
  ..$ linter       : chr "closed_curly_linter"
  ..- attr(*, "class")= chr "lint"

Looks like it enhances the paren_brace_linter so that it not only requires that there be a space between the right parenthesis and an opening curly brace, but also requires a space between the right parenthesis and the function body if they are in the same line. It is more like a paren_space_linter then.

If we are not to enhancing existing linters in this way, then we will need a new linter to specifically check this.

[kpagacz]

I have created a PR for this issue. Let me know what you think.
#830