formatR (version 0.7)

tidy.source: 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. 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 use

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'))

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

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.

References

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

The package vignette also contains some examples (see vignette('formatR', package = 'formatR').

Hadley's style guide: https://github.com/hadley/devtools/wiki/Style

See Also

parse, deparse, cat

Examples

library(formatR)

## use the 'text' argument
src = c("# a single line of comments is preserved", "1+1", "", "if(TRUE){", 
    "x=1  # inline comments", "}else{", "x=2;print('Oh no... ask the right bracket to go away!')}", 
    "1*3 # one space before this comment will become two!", "2+2+2    # 'short comments'", 
    "", "lm(y~x1+x2, data=data.frame(y=rnorm(100),x1=rnorm(100),x2=rnorm(100)))  ### only 'single quotes' are allowed in comments", 
    "1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1  ## comments after a long line", 
    "'a character string with \t in it'", "", paste("## here is a", paste(rep("long", 
        20), collapse = ""), "comment"))

## 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}"))