R: Reformat R code while preserving blank lines and comments

tidy.source {formatR}

R Documentation

Reformat R code while preserving blank lines and comments

Description

This function returns reformatted source code; it tries to preserve blank lines and comments, which is different with parse and deparse. It can also replace = with <- where = means assignments, and reindent code by a specified number of spaces (default is 4).

Usage

tidy.source(source = "clipboard", keep.comment = getOption("keep.comment", 
    TRUE), keep.blank.line = getOption("keep.blank.line", 
    TRUE), replace.assign = getOption("replace.assign", FALSE), 
    left.brace.newline = getOption("left.brace.newline", FALSE), 
    reindent.spaces = getOption("reindent.spaces", 4), output = TRUE, 
    text = NULL, width.cutoff = getOption("width"), ...)

Arguments

`source`	a character string: location of the source code (default to be the clipboard; this means we can copy the code to clipboard and use `tidy.souce()` without specifying the argument `source`)
`keep.comment`	whether to keep comments (`TRUE` by default)
`keep.blank.line`	whether to keep blank lines (`TRUE` by default)
`replace.assign`	whether to replace the assign operator `=` with `<-`
`left.brace.newline`	whether to put the left brace `{` to a new line (default `FALSE`)
`reindent.spaces`	number of spaces to indent the code (default 4)
`output`	output to the console or a file using `cat`?
`text`	an alternative way to specify the input: if it is `NULL`, the function will read the source code from the `source` argument; alternatively, if `text` is a character vector containing the source code, it will be used as the input and the `source` argument will be ignored
`width.cutoff`	passed to `deparse`: integer in [20, 500] determining the cutoff at which line-breaking is tried (default to be `getOption("width")`)
`...`	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

This function helps the users to tidy up their source code in a sense that necessary indents and spaces will be added, but comments will be preserved if keep.comment = TRUE. See the references to know how this function actually works.

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 <http://yihui.name> with substantial contribution from Yixuan Qiu <http://yixuan.cos.name>

References

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

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, keep.blank.line = TRUE)

## indent with 2 spaces
tidy.source(text = src, reindent.spaces = 2)

## discard comments!
tidy.source(text = src, keep.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, keep.blank.line = TRUE, file = f)

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

## use global options
options(keep.comment = TRUE, keep.blank.line = 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}"))

[Package formatR version 0.10 Index]