为什么"-1"不能减1？

我试图编写PDC2008简介到F#视频.我在下面显示的代码片段的最后一行中收到错误(演示者没有得到)"错误1此值不是函数,无法应用".我在Visual Studio 2008 shell上运行Fsharp-1.9.6.2.startPrice最后一行中的符号带有下划线红色,鼠标悬停时出现相同的错误.提前致谢!

type StockAnalyzer (lprices, days) = 
    let prices =
        lprices
        |> Seq.map snd
        |> Seq.take days
    static member GetAnalyzers (tickers,days) = 
        tickers
        |> Seq.map loadPrices
        |> Seq.map (fun prices -> new  StockAnalyzer (prices, days))
    member s.Return = 
        let  lastPrice = prices |> Seq.nth 0
        let  startPrice = prices |> Seq.nth (days - 1)
        lastPrice / startPrice  -1.

JaredPar.. 5

尝试在" - "和"1"之间加一个空格.F#编译器将-1解释为负值1而不是减1.

尝试在" - "和"1"之间加一个空格.F#编译器将-1解释为负值1而不是减1.