public static TResult Fold<T, TResult>(
	this IEnumerable<T> source,
	Func<T, T, T, T, TResult> folder
)

<ExtensionAttribute>
Public Shared Function Fold(Of T, TResult) ( 
	source As IEnumerable(Of T),
	folder As Func(Of T, T, T, T, TResult)
) As TResult

public:
[ExtensionAttribute]
generic<typename T, typename TResult>
static TResult Fold(
	IEnumerable<T>^ source, 
	Func<T, T, T, T, TResult>^ folder
)

[<ExtensionAttribute>]
static member Fold : 
        source : IEnumerable<'T> * 
        folder : Func<'T, 'T, 'T, 'T, 'TResult> -> 'TResult