fstocsexpr.fsx

let makeExpr x = 
    let rec func (m : Expression) ps = 
        match m with 
        | :? MethodCallExpression as x -> 
            let lambda = x.Arguments.[0] :?> LambdaExpression
            func lambda.Body (lambda.Parameters.[0] :: ps)
        | _ -> Expression.Lambda(m, ps |> List.rev)
    func (FSharp.Linq.RuntimeHelpers.LeafExpressionConverter.QuotationToExpression(x)) [] :?> Expression<_>

let (|F0|) (f : Expr<unit -> 'a>) : Expression<Func<'a>> = makeExpr f
let (|F1|) (f : Expr<'a -> 'b>) : Expression<Func<'a,'b>> = makeExpr f
let (|F2|) (f : Expr<'a -> 'b -> 'c>) : Expression<Func<'a,'b,'c>> = makeExpr f
let (|F3|) (f : Expr<'a -> 'b -> 'c -> 'd>) : Expression<Func<'a,'b,'c,'d>> = makeExpr f
let (|F4|) (f : Expr<'a -> 'b -> 'c -> 'd -> 'e>) : Expression<Func<'a,'b,'c,'d,'e>> = makeExpr f