Why Curly braces doesn't work instead of parenthesis calling apply method in scala -

afaik, in scala, 1 can choose use either curly braces {} or parenthesis () sending arguments method.

math.abs{-10}  def fx(x: int) = x * x fx{10}  list(1, 3, 5, 7) filter { _ > 5} 

so, why not applicable apply method in object list?

list.apply{"a", "b"}   // not compile 

when call method can pass parameters or inside parentheses or without them if has 1 argument. here fx {10} pass block of return type int {10} without parentheses. it's equivalent fx({10}).

here list(1, 3, 5, 7) filter { _ > 5} pass block { _ > 5} of return type int => boolean without parentheses.

in both above cases last block statement legal expression.

here list.apply{"a", "b"} pass without parentheses block {"a", "b"} equivalent list.apply({"a", "b"}) , "a", "b" statement illegal in scala.