laika.internal.rst.bundle.RewriteRules.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.internal.rst.bundle

import laika.ast.RewriteRules.RewriteRulesBuilder
import laika.ast.*
import laika.api.config.Config.ConfigResult
import laika.internal.rst.ast.{
  CustomizedTextRole,
  InterpretedText,
  SubstitutionDefinition,
  SubstitutionReference
}
import laika.internal.rst.ext.TextRoles.TextRole

/** The default rewrite rules that get applied to the raw document tree after parsing reStructuredText markup.
  * These rules are responsible for resolving  substitution references and interpreted text
  * which are specific to reStructuredText and get usually executed alongside the generic rules.
  *
  * @author Jens Halm
  */
private[bundle] class RewriteRules(textRoles: Seq[TextRole]) extends RewriteRulesBuilder {

  private val baseRoleElements: Map[String, String => Span] = textRoles.map { role =>
    (role.name, role.default)
  }.toMap

  private class DefaultRules(cursor: DocumentCursor) {

    private val substitutions: Map[String, Span] = cursor.target.content.collect {
      case SubstitutionDefinition(id, content, _) => (id, content)
    }.toMap

    private val textRoles: Map[String, String => Span] = cursor.target.content.collect {
      case CustomizedTextRole(id, f, _) => (id, f)
    }.toMap ++ baseRoleElements

    /** Function providing the default rewrite rules when passed a document instance.
      */
    val rewrite: laika.ast.RewriteRules = laika.ast.RewriteRules.forSpans {

      case SubstitutionReference(id, source, _) =>
        RewriteAction.Replace(
          substitutions.getOrElse(id, InvalidSpan(s"unknown substitution id: $id", source))
        )

      case InterpretedText(role, text, source, _) =>
        RewriteAction.Replace(
          textRoles.get(role).fold[Span](InvalidSpan(s"unknown text role: $role", source))(_(text))
        )

    }

  }

  /** Provides the default rewrite rules specific to reStructuredText
    *  for the specified document. These rules usually get executed
    *  alongside the generic default rules.
    */
  def apply(cursor: DocumentCursor): ConfigResult[laika.ast.RewriteRules] = Right(
    new DefaultRules(cursor).rewrite
  )

}