Anonymous record type inside discriminated union

Question

The F# tutorial includes the following snippet: ``` /// A record for a person's first and last name type Person = { First : string Last : string } /// define a discriminated union of 3 different kinds of employees type Employee = | Engineer of Person | Manager of Person * list // manager has list of reports | Executive of Person * list * Employee // executive also has an assistant ``` The fact that Manager and Executive are described as tuples offends my sensibilities (I'm easily offended). It strikes me as not terribly expressive. I tried to modify them as follows: ``` /// define a discriminated union of 3 different kinds of employees type Employee = | Engineer of Person | Manager of { Name: Person; Reports: Employee list } // manager has list of reports | Executive of { Name: Person; Reports: Employee list; Assistant: Employee} // executive also has an assistant ``` Sadly, the definitions of Manager and Executive now give an error: "This construct is deprecated;…

Accepted Answer

You can define mutually dependent types using `and`:

```
    type Employee = 
    | Engineer  of Person
    | Manager   of Manager            // manager has list of reports
    | Executive of Executive
    and Manager = { Name: Person; Reports: Employee list }
    and Executive = { Name: Person; Reports: Employee list; Assistant: Employee }
```

Anonymous record type inside discriminated union

Solution

Problem