Avalda FPGA Developer compiles "quoted" F# programs. Quotations are a feature in F# in which you wrap an F# expression in the quotation operators "<@@" and "@@>" so that the expression is treated like data and can be manipulated as such. The Avalda FPGA Developer api then allows the quoted expression to be translated to an XML encoding suitable for the core Avalda FPGA Developer compiler tool. So, write the following program and go to "Build" -> "Build GCDTutorial" to build a dll called gcdtutorial.dll: #light "off" namespace GCDTutorial type GCD = class static member gcdprogram = <@@ let rec gcd( (m : int), (n : int) ) = if m = 0 then n else gcd( n % m, m) in () @@> end