F# and the Intermediate Language
CIL (Common Intermediate Language), MSIL (Microsoft Intermediate Language), or IL, is the intermediate representation of the higher level .NET languages. As a part of the CLI (Common Language Infrastructure), IL serves as a human-readable intermediate language that is shared by all high-level .NET languages and is generated prior to the static or dynamic compilation of the machine-specific code.
Note
CIL and MSIL are effectively synonymous and there isn't much difference between the two. CIL is the terminology used in the CLI standard while MSIL is the product term for Microsoft's implementation of the standard. Both apply to the CPU-independent instruction set. The CLR executes after a high-level language such as F#, C#, VB, C++, Python, Ruby, and so on has compiled.
F# belongs to the family of the .NET IL languages such as C# and VB.NET. The compilers for these languages output IL; JIT (Just-In-Time) compilation converts the IL to native code on demand,...