Scala "overloaded method apply with alternatives" - 理解方法签名

Question

我使用外部库 plotly-scala，这是一个实现 Layout object.

的图形包

我需要使用 shape 参数，这似乎需要一个冗长的方法签名，我想了解原因以及是否有任何解决方法。

形状对象由同一作者here. It may or may not help to know that that scala-plotly classes rely on a 3rd party library定义。

我定义了工作和非工作示例：


// Related question: why do I have to use Some(...) everywhere?
// I'd prefer to write: new Shape(`type`="rect",xref="x", etc.)
val confidenceBand = new Shape(
    `type`=Some("rect"),
    xref=Some("x"),
    yref=Some("paper"),
    x0=Some("2.1"),
    y0=Some(0.0),
    x1=Some("3.2"),
    y1=Some(1.0),
    fillcolor=Some(Color.RGBA(156, 165, 196, 1.0)),
    opacity=Some(0.8),
    line=Some(Line(color = Color.RGBA(156, 165, 196, 1.0), width = 1.0)),
)

// No shape parameter -> non verbose signature, no need to use Some/None
val layout = Layout(
    title="Simulation",
    yaxis = Axis(
        title = "tbc")
)

// With shape parameter -> `overloaded method apply with alternatives:`
// See full error further down
val layout = Layout(
    title="Simulation",
    yaxis = Axis(
        title = "y"),
    shapes=Some(Seq(confidenceBand))
)

// With shape parameter and a verbose signature -> code compiles
val layout = Layout(
    title=Some("Simulation"),
    legend=None,
    width=None,
    height=None,
    showlegend=None,
    xaxis=None,
    yaxis = Some(Axis(
                    title = "y")),
    shapes=Some(Seq(confidenceBand)),
    xaxis1=None,
    xaxis2=None,
    xaxis3=None,
    xaxis4=None,
    yaxis1=None,
    yaxis2=None,
    yaxis3=None,
    yaxis4=None,
    barmode=None,
    autosize=None,
    margin=None,
    annotations=None,
    plot_bgcolor=None,
    paper_bgcolor=None,
    font=None,
    bargap=None,
    bargroupgap=None,
    hovermode=None,
    boxmode=None,
    scene=None,
    dragmode=None,
)

我能否采用第二种方法来工作，即具有形状参数但不必在代码中乱扔 None？

完整的错误信息：

cmd66.sc:1: overloaded method apply with alternatives:
  (title: Option[String],legend: Option[plotly.layout.Legend],width: Option[Int],height: Option[Int],showlegend: Option[scala.Boolean],xaxis: Option[plotly.layout.Axis],yaxis: Option[plotly.layout.Axis],xaxis1: Option[plotly.layout.Axis],xaxis2: Option[plotly.layout.Axis],xaxis3: Option[plotly.layout.Axis],xaxis4: Option[plotly.layout.Axis],yaxis1: Option[plotly.layout.Axis],yaxis2: Option[plotly.layout.Axis],yaxis3: Option[plotly.layout.Axis],yaxis4: Option[plotly.layout.Axis],barmode: Option[plotly.layout.BarMode],autosize: Option[scala.Boolean],margin: Option[plotly.layout.Margin],annotations: Option[Seq[plotly.layout.Annotation]],plot_bgcolor: Option[plotly.element.Color],paper_bgcolor: Option[plotly.element.Color],font: Option[plotly.layout.Font],bargap: Option[scala.Double],bargroupgap: Option[scala.Double],hovermode: Option[plotly.layout.HoverMode],boxmode: Option[plotly.layout.BoxMode],scene: Option[plotly.layout.Scene],dragmode: Option[String],shapes: Option[Seq[plotly.layout.Shape]])plotly.layout.Layout <and>
  (title: Option[String],legend: Option[plotly.layout.Legend],width: Option[Int],height: Option[Int],showlegend: Option[scala.Boolean],xaxis: Option[plotly.layout.Axis],yaxis: Option[plotly.layout.Axis],xaxis1: Option[plotly.layout.Axis],xaxis2: Option[plotly.layout.Axis],xaxis3: Option[plotly.layout.Axis],xaxis4: Option[plotly.layout.Axis],yaxis1: Option[plotly.layout.Axis],yaxis2: Option[plotly.layout.Axis],yaxis3: Option[plotly.layout.Axis],yaxis4: Option[plotly.layout.Axis],barmode: Option[plotly.layout.BarMode],autosize: Option[scala.Boolean],margin: Option[plotly.layout.Margin],annotations: Option[Seq[plotly.layout.Annotation]],plot_bgcolor: Option[plotly.element.Color],paper_bgcolor: Option[plotly.element.Color],font: Option[plotly.layout.Font],bargap: Option[scala.Double],bargroupgap: Option[scala.Double],hovermode: Option[plotly.layout.HoverMode],boxmode: Option[plotly.layout.BoxMode],scene: Option[plotly.layout.Scene])plotly.layout.Layout <and>
  ()plotly.layout.Layout <and>
  (title: String,legend: plotly.layout.Legend,width: Integer,height: Integer,showlegend: java.lang.Boolean,xaxis: plotly.layout.Axis,yaxis: plotly.layout.Axis,xaxis1: plotly.layout.Axis,xaxis2: plotly.layout.Axis,xaxis3: plotly.layout.Axis,xaxis4: plotly.layout.Axis,yaxis1: plotly.layout.Axis,yaxis2: plotly.layout.Axis,yaxis3: plotly.layout.Axis,yaxis4: plotly.layout.Axis,barmode: plotly.layout.BarMode,autosize: java.lang.Boolean,margin: plotly.layout.Margin,annotations: Seq[plotly.layout.Annotation],plot_bgcolor: plotly.element.Color,paper_bgcolor: plotly.element.Color,font: plotly.layout.Font,bargap: java.lang.Double,bargroupgap: java.lang.Double,hovermode: plotly.layout.HoverMode,boxmode: plotly.layout.BoxMode,scene: plotly.layout.Scene)plotly.layout.Layout
 cannot be applied to (title: String, yaxis: plotly.layout.Axis, shapes: Some[Seq[plotly.layout.Shape]])
val layout = Layout(
             ^
Compilation Failed

Answer 1

正如@LuisMiguelMejíaSuárez 在评论中明确解释的那样，答案在 Layout 的伴随对象中，它根据我们传递的 A 类型参数创建 Option[A] 参数。

apply 方法不包含 shapes 参数，因此出现了我描述的奇怪行为。

此外，使用链接方法 - class 构造函数中已弃用的警告建议 - 给了我我需要的东西：

val layout = Layout().
            withTitle("simulation").
            withYaxis(Axis(title = "y")).
            withShapes(Seq(confidenceBand))

Scala "overloaded method apply with alternatives" - 理解方法签名

Scala "overloaded method apply with alternatives" - understand method signatures

scala

plotly

data-class