P.6. Conventions Used in This Book

Italic

Is used to introduce new terms, as well as for email and URL addresses.

Constant width

Is used for code examples and fragments.

Constant width
          bold

Is used to highlight a section of code being discussed in the text.

Constant width italic

Is used for replaceable elements in code examples.

This is a note.

This is a warning.

This book uses callouts to denote "points of interest " in code listings. A callout is shown as a white number in a black circle; the corresponding number after the listing gives an explanation. Here's an example:

Roses are red,
   Violets are blue.     [1]
Some poems rhyme;
   This one doesn't.     [2]

[1] Violets actually have a color value of #9933cc.

[2] This poem uses the literary device known as a "surprise ending."