The Book of F#

Chapter 9. Can I Quote You on that?

Another feature introduced to the .NET Framework with LINQ is expression trees. Often using the same syntax as lambda expressions, expression trees compile not to executable code but instead into a tree structure that describes the code and can be parsed for translation to other forms. This type of programming is often called metaprogramming. Just as we can think of metadata as data that describes data, we can think of metaprogramming as code that describes code.

This chapter isn’t about expression trees, though; it’s about a similar construct in F# called a quoted expression, also known as a code quotation. Quoted expressions address the same basic problem as expression trees, but they take a fundamentally different ...