Question

Is there an “official” naming / casing convention for F#?

I’m always in doubt of using C# style or not:

Class.MyFunctionName or Module.my_function_name

In F# you’re meant to mix BCL classes and F# library ones: they have different casing and the code looks very ugly.

Answer 1

Yes, there is confusion, because F# has morphed from OCaml to .Net over the years. Basically, the naming conventions are a "breaking change" – old code is inconsistent with new code.

However, the May 2009 CTP has settled the issue.

The Release Notes say…

Standard Library Naming Conventions

The naming conventions adopted for the F# library are as follows:

• All .NET and F# OO code uses PascalCase according to existing .NET guidelines

• The F# functional programming operators such as List.map are for use in F# internal implementation code. This kind of code uses camelCase for operator names

• Underscores should not be used.

So, your question…

Class.MyFunctionName or Module.my_function_name 

The answer is

Class.MyFunctionName and Module.MyFunctionName (but see edit below!)

(applying rule 1 above).

— Edit. Nov 2, 2019 —

The current guidelines recommend camelCase for functions at module level, so it’s

Module.myFunctionName

Which then makes production code consistent with the F# libraries (eg. List.averageBy)