In krlmlr/styler: Non-Invasive Pretty Printing of R Code

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  results = "hide"
)

styler::cache_deactivate()

knitr::knit_engines$set(list(
  styler = function(options) {
    options$comment <- ""
    knitr::engine_output(
      options,
      {
        before <- options$code
        after <- as.character(styler::style_text(options$code, strict = FALSE))
        if (!identical(trimws(before, "right"), after)) {
          stop(
            "Before unlike after. Before:", paste(before, sep = "\n"),
            "After: ", paste(after, sep = "\n")
          )
        }
        after
      },
      ""
    )
  }
))

This vignette shows how output from styler might differ when strict = FALSE. For brevity, we don't show the output of strict = TRUE, but it should be pretty simple for the user to derive it from the bullet point(s) or simply paste the code in the console to see the output.

library(styler)

• multi-line function declarations without curly braces are tolerated.

function()
  NULL

• Spaces before opening parenthesis, tilde as well as around comments and math token must be at least one, not exactly one.

1  +    (1 + 3)
1 ~  more()   #   comment

• More than one line break is tolerated before closing curly brace and line breaks between curly and round braces are not removed.

test({
  1

}
)

• Multi-line calls don't put the closing brace on a new line nor trigger a line break after the opening brace.

call(
  this)
call(2,
  more
)

• No line break inserted after pipes nor ggplot2 or pipe expressions.

ggplot2::ggplot(data, aes(x, y)) + geom_line() + scale_x_continuous()

this %>% is() %>% a() %>% long() %>% pipe()

• ifelse statements don't get curly braces added when multi-line.

if (TRUE) 3  else 
  5

krlmlr/styler documentation built on April 8, 2024, 7:53 p.m.