AsArgument adds an allocation

[wsargent]

Statement interpolation is faster than using a statement apply:

class StatementBenchmark {

  @Benchmark
  def statementFromInterpolation(blackhole: Blackhole): Unit = {
    val arg1 = "one"
    val arg2 = "two"
    val arg3 = "three"
    blackhole.consume(st"Hello world $arg1, $arg2, $arg3")
  }

  @Benchmark
  def statementFromApply(blackhole: Blackhole): Unit = {
    val arg1 = "one"
    val arg2 = "two"
    val arg3 = "three"
    blackhole.consume(
      Statement(message = "Hello world {}, {}, {}", arguments = Arguments(arg1, arg2, arg3))
    )
  }

  @Benchmark
  def statementFromArray(blackhole: Blackhole): Unit = {
    val arg1 = "one"
    val arg2 = "two"
    val arg3 = "three"
    blackhole.consume(
      Statement(
        message = "Hello world {}, {}, {}",
        arguments = Arguments.fromArray(Array(Argument(arg1), Argument(arg2), Argument(arg3)))
      )
    )
  }

}

yields

[info] Benchmark                                      Mode  Cnt   Score   Error  Units
[info] StatementBenchmark.statementFromApply          avgt    5  73.042 ± 2.727  ns/op
[info] StatementBenchmark.statementFromArray          avgt    5  28.677 ± 0.653  ns/op
[info] StatementBenchmark.statementFromInterpolation  avgt    5  29.063 ± 4.497  ns/op

The apply method is probably slower because it uses AsArgument, which the interpolation and array does not use -- it's macro based instead.

So it may be possible to save on an allocation by using a macro for Arguments.apply here.

[wsargent]

Fixed by #148