Exception Types (F#)
There are two categories of exceptions in F#: .NET exception types and F# exception types. This topic describes how to define and use F# exception types.
In the previous syntax, exception-type is the name of a new F# exception type, and argument-type represents the type of an argument that can be supplied when you raise an exception of this type. You can specify multiple arguments by using a tuple type for argument-type.
A typical definition for an F# exception resembles the following.
You can generate an exception of this type by using the raise function, as follows.
You can use an F# exception type directly in the filters in a try...with expression, as shown in the following example.
exception Error1 of string // Using a tuple type as the argument type. exception Error2 of string * int let function1 x y = try if x = y then raise (Error1("x")) else raise (Error2("x", 10)) with | Error1(str) -> printfn "Error1 %s" str | Error2(str, i) -> printfn "Error2 %s %d" str i function1 10 10 function1 9 2
The exception type that you define with the exception keyword in F# is a new type that inherits from Exception.