Break up long comments to multiple lines

break.comments.R

  # Do not need to load this library but need it installed
# library(tm)
library(stringr)

  # get dummy text
loremipsum <- system.file("texts", "loremipsum.txt", package = "tm")

  #A really long single line comment
comment <- paste('#', paste(readLines(loremipsum),collapse=''))


break.comment <- function(x, width=getOption('width')){

  loc <- last.blank.loc <- last.break <- 1

    # move through each character one by one...
  while(loc < nchar(x)){

      # save the location if the current character can be broken on
    if( !is.na( str_match( str_sub( x, loc, loc ),'[[:blank:]]' ) ) )
      last.blank.loc <- loc

      # check if we hit the end of our line width
    if((loc - last.break + 1) == width){
      
        # break the line at the last blank space
      last.blank.character <- str_sub(x, last.blank.loc, last.blank.loc)

        # break the line
      str_sub(x, last.blank.loc, last.blank.loc) <- 
        paste(last.blank.character,'\n# ',sep='')

        # reset last break location
      last.break <- last.blank.loc + 1
        # added three characters
      last.blank.loc <- last.blank.loc + 3
      loc <- last.blank.loc
    }
      # advance next character
    loc <- loc + 1

  }

  x

}

cat(break.comment( comment ))