Conventions

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, user input, and Twitter handles are shown as follows: " You can also use the #help;; directive to list other directives inside FSI."

A block of code is set as follows:

val cubeMe : x:int -> int
> > cubeMe 9;;
val it : int = 729

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

square 10;;
^^^^^^
error FS0039: The value or constructor 'square' is not defined

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: "When this function is executed in F# interactive, you can immediately see the results upon invocation as in the following screenshot."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.