In May 2006 Hampton Catlin introduced us to HAML. A lightweight markup preprocessor language that uses indentation (whitespace) to separate blocks. HAML replaces the more common HTML syntax <tag> ... </tag> with a simpler, more lightweight syntax %tag. HAML's true strength lies within it's use of indentation to determine selector nesting and block separation.
In this section I will discuss the differences between HTML and HAML and how these ideas inspired Sass.