Fundamentally it's macros and homoiconicity of code and data that give lisp it's expressive power. Combined they grant you the power to inject new syntax / dom

Fundamentally it's macros and homoiconicity of code and data that give lisp it's expressive power. Combined they grant you the power to inject new syntax / domain specific languages (DSLs) directly into your code. Any new syntax you create can look like normal lisp or can have different syntax evaluation rules like infix math notation [1]. A number of years ago I did a short write-up on stack overflow giving a basic explanation of how macros work in common lisp which may be worth a read [2]. Macros in general work by being a syntax tree -> syntax tree transformation. The neat trick is it's not a static pattern like C - you can leverage functions, conditions, etc to build that syntax tree. As for comprehensions themselves, if you want to see the power of lisp look at the loop macro. It's a single macro yet gives you the power of normal control loops, list comprehensions, for-each all rolled into one package. [3] [1] http://data-sorcery.org/2010/05/14/infix-math/ http://data-sorcery.org/2010/05/14/infix-math/ [2] http://www.gigamonkeys.com/book/loop-for-black-belts.html http://www.gigamonkeys.com/book/loop-for-black-belts.html [3] http://stackoverflow.com/questions/267862/what-makes-lisp-macros-so-special/4621882#4621882 http://stackoverflow.com/questions/267862/what-makes-lisp-ma...