caseapp.core.argparser.FlagAccumulatorArgParser.scala Maven / Gradle / Ivy
package caseapp.core.argparser
import caseapp.core.{Counter, Error}
import caseapp.{@@, Tag}
final case class FlagAccumulatorArgParser[T](
description: String,
parse: (Option[T], Option[String]) => Either[Error, T]
) extends ArgParser[T] {
def apply(current: Option[T], value: String): Either[Error, T] =
parse(current, Some(value))
override def optional(current: Option[T], value: String): (Consumed, Either[Error, T]) =
(Consumed(false), parse(current, None))
override def apply(current: Option[T]): Either[Error, T] =
parse(current, None)
override def isFlag: Boolean =
true
}
object FlagAccumulatorArgParser {
def from[T](description: String)(parse: (Option[T], Option[String]) => Either[Error, T]): FlagAccumulatorArgParser[T] =
FlagAccumulatorArgParser(description, parse)
val counter: FlagAccumulatorArgParser[Int @@ Counter] =
from("counter") { (prevOpt, _) =>
Right(Tag.of(prevOpt.fold(0)(Tag.unwrap) + 1))
}
def list[T](implicit parser: ArgParser[T]): FlagAccumulatorArgParser[List[T]] =
from(parser.description + "*") { (prevOpt, s) =>
s.fold(parser(None))(parser(None, _))
.right
.map { t =>
// inefficient for big lists
prevOpt.getOrElse(Nil) :+ t
}
}
def vector[T](implicit parser: ArgParser[T]): FlagAccumulatorArgParser[Vector[T]] =
from(parser.description + "*") { (prevOpt, s) =>
s.fold(parser(None))(parser(None, _))
.right
.map { t =>
prevOpt.getOrElse(Vector.empty) :+ t
}
}
def option[T](implicit parser: ArgParser[T]): FlagAccumulatorArgParser[Option[T]] =
from(parser.description + "?") { (prevOpt, s) =>
s.fold(parser(prevOpt.flatten))(parser(prevOpt.flatten, _))
.right
.map(Some(_))
}
}