Package 'formatR'

A Shiny app to format R code

Description

Run a Shiny app that formats R code via tidy_source(). This app uses input widgets, such as checkboxes, to pass arguments to tidy_source().

Usage

tidy_app()

Examples

if (interactive()) formatR::tidy_app()

---

Format all R scripts under a directory, or specified R scripts

Description

Look for all R scripts under a directory (using the pattern "[.][RrSsQq]$"), then tidy them with tidy_source(). If successful, the original scripts will be overwritten with reformatted ones. Please back up the original directory first if you do not fully understand the tricks used by tidy_source(). tidy_file() formats scripts specified by file names.

Usage

tidy_dir(path = ".", recursive = FALSE, ...)

tidy_file(file, ...)

Arguments

path	The path to a directory containning R scripts.
recursive	Whether to recursively look for R scripts under path.
...	Other arguments to be passed to tidy_source().
file	A vector of filenames.

Value

Invisible NULL.

Author(s)

Yihui Xie (tidy_dir) and Ed Lee (tidy_file)

See Also

tidy_source()

Examples

library(formatR)

path = tempdir()
file.copy(system.file("demo", package = "base"), path, recursive = TRUE)
tidy_dir(path, recursive = TRUE)

---

Insert output to source code

Description

Evaluate R code by chunks, then insert the output to each chunk. As the output is masked in comments, the source code will not break.

Usage

tidy_eval(
  source = "clipboard",
  ...,
  file = "",
  prefix = "## ",
  envir = parent.frame()
)

Arguments

source	The input file name (by default the clipboard; see tidy_source()).
...	Other arguments passed to tidy_source().
file	The file name to write to via cat().
prefix	The prefix to mask the output.
envir	The environment in which to evaluate the code. By default the parent frame; set envir = NULL or envir = new.env() to avoid the possibility of contaminating the parent frame.

Value

Evaluated R code with corresponding output (printed on screen or written to a file).

References

https://yihui.org/formatR/

Examples

library(formatR)
## evaluate simple code as a character vector
tidy_eval(text = c("a<-1+1;a", "matrix(rnorm(10),5)"))

## evaluate a file
tidy_eval(system.file("format", "messy.R", package = "formatR"))

---

Substitute the magrittr pipe with R's native pipe operator

Description

Parse the R code in the RStudio editor, identify %>%, and substitute with |>.

Usage

tidy_pipe()

Note

Currently this function only works inside the RStudio IDE, and may be extended in future to deal with arbitrary R code elsewhere.

Examples

formatR::tidy_pipe()

---

Reformat R code in RStudio IDE

Description

If any R code is selected in the RStudio source editor, this function reformats the selected code; otherwise it reformats the current open file (if it is unsaved, it will be automatically saved).

Usage

tidy_rstudio(...)

Arguments

...	Arguments to be passed to tidy_source(), among which the indent argument will respect the value you set for the number of spaces for indentation in RStudio.

Note

If the output is not what you want, you can undo the change in the editor (Ctrl + Z or Command + Z).

Examples

formatR::tidy_rstudio()
formatR::tidy_rstudio(args.newline = TRUE)

---

Reformat R code

Description

Read R code from a file or the clipboard and reformat it. This function is based on parse() and deparse(), but it does several other things, such as preserving blank lines and comments, substituting the assignment operator = with <-, and re-indenting code with a specified number of spaces.

Usage

tidy_source(
  source = "clipboard",
  comment = getOption("formatR.comment", TRUE),
  blank = getOption("formatR.blank", TRUE),
  arrow = getOption("formatR.arrow", FALSE),
  pipe = getOption("formatR.pipe", FALSE),
  brace.newline = getOption("formatR.brace.newline", FALSE),
  indent = getOption("formatR.indent", 4),
  wrap = getOption("formatR.wrap", TRUE),
  width.cutoff = getOption("formatR.width", getOption("width")),
  args.newline = getOption("formatR.args.newline", FALSE),
  output = TRUE,
  text = NULL,
  ...
)

Arguments

source	A character string: file path to the source code (defaults to the clipboard).
comment	Whether to keep comments.
blank	Whether to keep blank lines.
arrow	Whether to substitute the assignment operator = with <-.
pipe	Whether to substitute the magrittr pipe %>% with R's native pipe operator |>.
brace.newline	Whether to put the left brace { to a new line.
indent	Number of spaces to indent the code.
wrap	Whether to wrap comments to the linewidth determined by width.cutoff (roxygen comments will never be wrapped).
width.cutoff	An integer in [20, 500]: if a line's character length is at or over this number, the function will try to break it into a new line. In other words, this is the lower bound of the line width. See ‘Details’ if an upper bound is desired instead.
args.newline	Whether to start the arguments of a function call on a new line instead of after the function name and ( when the arguments cannot fit one line.
output	Whether to output to the console or a file using cat().
text	An alternative way to specify the input: if NULL, the function will use the source argument; if a character vector containing the source code, the function will use this and ignore the source argument.
...	Other arguments passed to cat(), e.g. file (this can be useful for batch-processing R scripts, e.g. tidy_source(source = 'input.R', file = 'output.R')).

Details

A value of the argument width.cutoff wrapped in I() (e.g., I(60)) will be treated as the upper bound of the line width. The corresponding argument to deparse() is a lower bound, so the function will perform a binary search for a width value that can make deparse() return code with line width smaller than or equal to the width.cutoff value. If the search fails, a warning will signal, suppressible by global option options(formatR.width.warning = FALSE).

Value

A list with components

text.tidy	the reformatted code as a character vector
text.mask	the code containing comments, which are masked in assignments or with the weird operator

.

Note

Be sure to read the reference to know other limitations.

Author(s)

Yihui Xie <https://yihui.org> with substantial contribution from Yixuan Qiu <https://yixuan.blog>

References

https://yihui.org/formatR/ (an introduction to this package, with examples and further notes)

See Also

parse(), deparse()

Examples

library(formatR)

## a messy R script
messy = system.file("format", "messy.R", package = "formatR")
tidy_source(messy)

## use the 'text' argument
src = readLines(messy)

## source code
cat(src, sep = "\n")

## the formatted version
tidy_source(text = src)

## preserve blank lines
tidy_source(text = src, blank = TRUE)

## indent with 2 spaces
tidy_source(text = src, indent = 2)

## discard comments!
tidy_source(text = src, comment = FALSE)

## wanna see the gory truth??
tidy_source(text = src, output = FALSE)$text.mask


## tidy up the source code of image demo
x = file.path(system.file(package = "graphics"), "demo", "image.R")

# to console
tidy_source(x)

# to a file
f = tempfile()
tidy_source(x, blank = TRUE, file = f)

## check the original code here and see the difference
file.show(x)
file.show(f)

## use global options
options(comment = TRUE, blank = FALSE)
tidy_source(x)

## if you've copied R code into the clipboard
if (interactive()) {
    tidy_source("clipboard")
    ## write into clipboard again
    tidy_source("clipboard", file = "clipboard")
}

## the if-else structure
tidy_source(text = c("{if(TRUE)1 else 2; if(FALSE){1+1", "## comments", "} else 2}"))

---

Show the usage of a function

Description

Print the reformatted usage of a function. The arguments of the function are searched by argsAnywhere(), so the function can be either exported or non-exported from a package. S3 methods will be marked.

Usage

usage(
  FUN,
  width = getOption("width"),
  tidy = TRUE,
  output = TRUE,
  indent.by.FUN = FALSE,
  fail = c("warn", "stop", "none")
)

Arguments

FUN	The function name.
width	The width of the output.
tidy	Whether to reformat the usage code.
output	Whether to print the output to the console (via cat()).
indent.by.FUN	Whether to indent subsequent lines by the width of the function name (see “Details”).
fail	A character string that represents the action taken when the width constraint is unfulfillable. "warn" and "stop" will signal warnings and errors, while "none" will do nothing.

Details

Line breaks in the output occur between arguments. In particular, default values of arguments will not be split across lines.

When indent.by.FUN is FALSE, indentation is set by the option getOption("formatR.indent", 4L), the default value of the indent argument of tidy_source().

Value

Reformatted usage code of a function, in character strings (invisible).

See Also

tidy_source()

Examples

library(formatR)
usage(var)

usage(plot)

usage(plot.default)  # default method
usage("plot.lm")  # on the 'lm' class

usage(usage)

usage(barplot.default, width = 60)  # output lines have 60 characters or less

# indent by width of 'barplot('
usage(barplot.default, width = 60, indent.by.FUN = TRUE)

## Not run: 
# a warning is raised because the width constraint is unfulfillable
usage(barplot.default, width = 30)

## End(Not run)

---