F# 2 weeks later

21 Aug 2015

Since I’ve been without an assignment I’ve had the time to look into F# more.

Where did I find material?

• fsharpforfunandprofit
• functional programming on slack
• stackoverflow

Why did I start looking into F# again?

I share the office with Fredrik Forssen. I find his love of F# inspiring.

Things I’ve found that delighted me:

• Less ceremony to declare classes, records, methods and functions (when you get used to how you write it)
• Easier to compose things (for instance if you want to create a chain in order to use many different classes together for an import)
• Monad support (and yes, I know that these things can very easily be abused)
• Package manager and Build tool that works well together (paket and fake).
• Records defined in F# are like hand coded readonly classes with IEquatable and IComparable implemented

I’ve previously found the following sweet when looking at the language:

• Immutable by default
• Language construct to create a clone of a record but with different values for some fields
• Language construct to match more than hard coded strings, enums and integers

What is kind of annoying about the language (and tools related to it)

• If you forget to add an equals sign to a type or module declaration you get weird compiler errors
• Gui tooling is still a bit alpha (the command line version works great)
• It’s easy to create a F# project where you need to manually edit the fsproj file in order to get it to work on mono and windows (this was a problem in the early days of NuGet)
• Almost all the library methods in .net becomes a tuple parameter in F#, this is a bit confusing since it looks like an ordinary function call in C#
• Exposing F# Option on your types makes it harder to interact with your F# code from C#

    using OptionalUrl = Microsoft.FSharp.Core.FSharpOption<Customers.Url>;
    ...
       var customer = new Customer(
          ...
          pictureUri: OptionalUrl.Some(new Url("http://someurl.com/something?some=asd"))
       );

Tags

• F#

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