Scala "is not a member of" when chaining method calls without periods and parameters

Question

Continuation of my work in: Scala "does not take parameters" when chaining method calls without periods

Given the accepted answer, this time I want to pass a parameter to one of the methods.

Original suggestion:

object and

class Greeter {
  def hi(a: and.type) = { print("hi"); this }
  def hello = { print("hello"); this }
}

new Greeter hi and hello

My new code:

object and

class Greeter {
  def hi(name: String) = { print("hi" + name); this }
  def hi(name: String, a: and.type): Greeter = hi(name)
  def hello = { print("hello"); this }
}

but when I: new Greeter hi "Miguel" and

I get: error: value and is not a member of Greeter

putting the parentheses and comma works: new Greeter hi ("Miguel", and)

Answer 1

In Scala, there must always be parentheses around a parameter list with more than one parameter. Leaving those off is simply not possible.

new Greeter hi "Miguel" and is interpreted as (new Greeter).hi("Miguel").and, i.e. it's trying to invoke an and method on a Greeter object.

Answer 2

The compiler isn't always able to infer parantheses. My rule is simply that if it blows up without them I add them and move on. Usually, I'll later learn the language further and then come back and clean up my code in ways that removes them (if they are part of a DSL). But, i've found trying to do so upfront takes 20 times longer to find an answer. Could've released the software much sooner if I just accepted a couple mild blemishes.