In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, and user input are shown as follows: "We can import modules with the import statement."

A block of code is set as follows:

def occurrencesOf[A](elem:A, collection:List[A]):List[Int] = {
  for { 
    (currentElem, index) <- collection.zipWithIndex
    if (currentElem == elem)
  } yield index
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

def occurrencesOf[A](elem:A, collection:List[A]):List[Int] = {
  for { 
    (currentElem, index) <- collection.zipWithIndex
    if (currentElem == elem)
  } yield index
}

Any command-line input or output is written as follows:

scala> val nTosses = 100
nTosses: Int = 100

scala> def trial = (0 until nTosses).count { i =>
   util.Random.nextBoolean() // count the number of heads
}
trial: Int

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Clicking the Next button moves you to the next screen."