Empty lines in function calls results in an error

[Iain-S]

R version 4.1.2 (2021-11-01)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS Big Sur 10.16
Locale: en_GB.UTF-8 / en_GB.UTF-8 / en_GB.UTF-8 / C / en_GB.UTF-8 / en_GB.UTF-8
Package version:
formatR_1.11.1

Minimal Reproducible Example

At least some of the time (perhaps all of the time) having two empty lines between function call parens causes formatR to error. However, it appears to be valid R syntax (verified by running it in R).

mre.R

print(


)

> formatR::tidy_file("mre.R", indent=2, arrow=TRUE, args.newline=TRUE)
tidying mre.R
Error in base::parse(text = code, keep.source = FALSE) :
  <text>:3:1: unexpected symbol
2: invisible(".BeGiN_TiDy_IdEnTiFiEr_HaHaHa.HaHaHa_EnD_TiDy_IdEnTiFiEr")
3: invisible

Conversely, having only one empty line in the function call does not throw an error but does result in incorrect behaviour

mre2.R (before)

print(

)

> formatR::tidy_file("mre2.R")
tidying mre2.R

mre2.R (after)

print() print()

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[yihui]

I'm afraid that this is a known limitation: https://yihui.org/formatr/#6-further-notes Not all blank lines can be correctly formatted. Sorry.

[Iain-S]

OK, thanks. I can see that the files are correctly formatted if I set blank=FALSE and comment=FALSE.

Do you think that the whitespace formatting could be improved or is it a limitation of R, as a language?

[yihui]

It's not a limitation of R, but me. I feel it would be hard to support multiple empty lines as in your first example. For the second example, it looks like a bug. I don't know why two instances of print() were generated. @iqis Do you have time to investigate?