Introduce `scala-indent:defition-parameter-scaling-factor`

[mzhaom]

to control whether the parameter list of function/class should have a different indentation level.

See discussion in #172

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[hvesalai]

Thank you for the PR. It looks promising, but I would like to understand it better first.

It seems you want to only indent definition lists, but not function call lists. Why is this?

def foo(s: String, b: Int)

foo(
    "shouldn't this row have an indent of four spaces compared to the function name?",
    0
)

[mzhaom]

Thank you for the PR. It looks promising, but I would like to understand it better first.

It seems you want to only indent definition lists, but not function call lists. Why is this?

def foo(s: String, b: Int)

foo(
    "shouldn't this row have an indent of four spaces compared to the function name?",
    0
)

Yeah, that's the databricks scala style, I don't know why the chose so. https://github.com/databricks/scala-style-guide#indent I'm still thinking about how to handle extends and with after class parameter list.

For classes whose header doesn't fit in two lines, use 4 space indentation for its parameters, put each in each line, put the extends on the next line with 2 space indent, and add a blank line after class header.

class Foo(
    val param1: String,  // 4 space indent for parameters
    val param2: String,
    val param3: Array[Byte])
  extends FooInterface  // 2 space indent here
  with Logging {

  def firstMethod(): Unit = { ... }  // blank line above
}

For method and class constructor invocations, use 2 space indentation for its parameters and put each in each line when the parameters don't fit in two lines.

foo(
  someVeryLongFieldName,  // 2 space indent here
  andAnotherVeryLongFieldName,
  "this is a string",
  3.1415)

new Bar(
  someVeryLongFieldName,  // 2 space indent here
  andAnotherVeryLongFieldName,
  "this is a string",
  3.1415)

[hvesalai]

@mzhaom did you have a chance to look at my other comments