What is FOM?

Fom is a code generation tool to people using a funcitonal style of programming to update user interfaces.

It achieves this by making it easy to create "diffs" between two immutable objects.

For example, itf we have this type

    type Person =
        {
            Name : string
            Age : int
        }

FOM makes it possible to create diffs of two Person objects to tell what changed. This is useful when writing data-backed UIs.

For example, if I download two Person objects, I can tell the difference:

    let person1 = { Name = "Frank"; Age = 39 }

    let person2 = { Name = "Frank"; Age = 40 }

    let whatChanged = person2 - person1

No, whatChanged will have all None-fields except the AgeDiff field will have the new value.

Then diff looks like this:

    type PersonDiff =
         {
            NameDiff : string option
            AgeDiff : string option
         }
         static member (-) (x : Person, y: Person) =
             {
                 NameDiff = if x.Name <> y.Name then Some x.Name else None
                 AgeDiff = if x.Age <> y.Age then Some x.Age else None
             }