ResTTryMapTOut Method

Returns the error when IsErr. Otherwise, tries to map into Ok(map(val)) in a try-catch block and returns the Err if it throws.
C#
static Res<User> TryGetUser() { .. }
static long PutUserToDbGetId(User user) {
    // method that writes the user to a database table and returns back the auto-generated id/primary-key
    // might fail and throw!
}

Res<long> id = TryGetUser().TryMap(PutUserToDbGetId);
// equivalently:
Res<long> id = TryGetUser().TryMap(user => PutUserToDbGetId(user));
// Res<long> id will be:
// - Err(called on Err) when TryGetUser returns Err,
// - Err(relevant error message) when TryGetUser returns Ok(user) but the database transaction throws an exception,
// - Ok(id) when TryGetUser returns Ok(user), the database transaction succeeds and returns the auto-generated id.

// it provides a shorthand for the following verbose/unpleasant version:
Opt<User> user = TryGetUser();
Res<long> id;
if (user.IsNone)
    id = Err<long>("no user");
else
{
    try
    {
        id = Ok(PutUserToDb(user.Unwrap()));
    }
    catch (Exception e)
    {
        id = Err<long>("db-operation failed, check the exception message: " + e.Message);
    }
}

Definition

Namespace: Orx.Fun.Result
Assembly: Orx.Fun.Result (in Orx.Fun.Result.dll) Version: 1.3.0+344c8bdd6f720ccfb2d8db7c61b76cf02be18f5f
C#
public Res<TOut> TryMap<TOut>(
	Func<T, TOut> map,
	string name = ""
)

Parameters

map  FuncT, TOut
Function (T -> TOut) to be called in try-catch block to get the result when Ok; will not be called when Err.
name  String  (Optional)
Name of the map function/operation; to be appended to the error messages if the function throws. Omitting the argument will automatically be filled with the function's expression in the caller side.

Type Parameters

TOut

[Missing <typeparam name="TOut"/> documentation for "M:Orx.Fun.Result.Res`1.TryMap``1(System.Func{`0,``0},System.String)"]

Return Value

ResTOut

See Also