laika.ast.Options.scala Maven / Gradle / Ivy

/*
 * Copyright 2012-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package laika.ast

/** Options for customizable elements.
  *
  * For creating new instances you can use the various factory objects.
  * Example for creating an instance with an id and two styles applied:
  *
  * {{{
  *  val options = Id("myId") + Styles("style1","style2")
  * }}}
  *
  * Likewise it is also often more convenient to use the corresponding extractors for pattern matching.
  */
sealed abstract class Options {

  /** The id of this element.
    * Has to be unique across all element types of a document,
    * including the ids of `LinkTarget` instances.
    */
  def id: Option[String]

  /** Style names that may have an influence on rendering of this element.
    */
  def styles: Set[String]

  /** Indicates whether this options instance is empty,
    * meaning neither an id nor any styles are assigned to it.
    */
  def isEmpty: Boolean

  /** Merges these options with the specified options.
    * If the id has been set in both instances, the other instance overrides this one.
    */
  def + (other: Options): Options

}

/** Companion for the Options trait.
  */
object Options {

  private final case class Impl(id: Option[String], styles: Set[String])
      extends Options {
    override def productPrefix = "Options"

    def isEmpty: Boolean = id.isEmpty && styles.isEmpty

    def + (other: Options): Options = Impl(other.id.orElse(id), styles ++ other.styles)
  }

  val empty: Options = Impl(None, Set())

  def apply(id: Option[String] = None, styles: Set[String] = Set()): Options =
    if (id.isEmpty && styles.isEmpty) empty
    else Impl(id, styles)

}

/** Factory and extractor for an `Options` instance with an id.
  */
object Id {
  def apply(value: String): Options           = Options(id = Some(value))
  def unapply(value: Options): Option[String] = value.id
}

/** Factory and extractor for an `Options` instance with style names.
  */
object Styles {
  def apply(values: String*): Options                 = Options(styles = values.toSet)
  def apply(values: Set[String]): Options             = Options(styles = values)
  def unapplySeq(value: Options): Option[Seq[String]] = Some(value.styles.toSeq)
}

/** Constants for style names wrapped in Options instances which are commonly used by Laika's core parsers and rewrite rules. */
object Style {

  val title: Options         = Styles("title")
  val section: Options       = Styles("section")
  val sectionNumber: Options = Styles("section-number")

  val nav: Options             = Styles("nav")
  val navList: Options         = Styles("nav-list")
  val navHeader: Options       = Styles("nav-header")
  val navNode: Options         = Styles("nav-node")
  val navLeaf: Options         = Styles("nav-leaf")
  val active: Options          = Styles("active")
  val breadcrumb: Options      = Styles("breadcrumb")
  val bookmark: Options        = Styles("bookmark")
  def level(lev: Int): Options = Styles("level" + lev)

  val alignCenter: Options  = Styles("align-center")
  val alignLeft: Options    = Styles("align-left")
  val alignRight: Options   = Styles("align-right")
  val keepTogether: Options = Styles("keep-together")

  val citation: Options      = Styles("citation")
  val footnote: Options      = Styles("footnote")
  val footnoteLabel: Options = Styles("footnote-label")

  val label: Options       = Styles("label")
  val attribution: Options = Styles("attribution")
  val caption: Options     = Styles("caption")
  val legend: Options      = Styles("legend")
  val figure: Options      = Styles("figure")

  val runtimeMessage: Options = Styles("runtime-message")
  val noHighlight: Options    = Styles("nohighlight")

}