r.pamflet-knockoff_2.10.0.6.0.source-code.fenced.scala Maven / Gradle / Ivy

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Extensions to the Knockoff Markdown parser

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package pamflet

import com.tristanhunt.knockoff._
import scala.util.parsing.input.{ CharSequenceReader, Position, Reader }

trait FencedDiscounter extends Discounter {
  override def newChunkParser : ChunkParser =
    new ChunkParser with FencedChunkParser
  override def blockToXHTML: Block => xml.Node = block => block match {
    case FencedCodeBlock(text, _, language) =>
      fencedChunkToXHTML(text, language)
    case _ => super.blockToXHTML(block)
  }
  def fencedChunkToXHTML(text: Text, language: Option[String]) =
    { text.content }
}

trait FencedChunkParser extends ChunkParser {
  override def chunk : Parser[ Chunk ] = {
    horizontalRule | leadingStrongTextBlock | leadingEmTextBlock | bulletItem |
    numberedItem | indentedChunk | header | blockquote | linkDefinition |
    htmlBlock | fencedChunk | textBlockWithBreak | textBlock | emptyLines | emptySpace
  }
  
  def fencedChunk : Parser[ Chunk ] =
    fence ~> opt(brush) ~ emptyLine ~
      rep1(unquotedTextLine | emptyLine) <~ fence <~ emptyLine ^^ {
        case (brush ~ _) ~ lines =>
          FencedChunk(foldedString(lines), brush.map { _.content })
      }

  def brush : Parser[Chunk] =
    """[ ]*[^\n]+""".r ^^ { b => TextChunk(b.trim) }

  def fence : Parser[Chunk] =
    "```" ^^ { _ => EmptySpace("") }

  def unquotedTextLine : Parser[ Chunk ] =
    """(?!```)[^\n]+\n""".r ^^ { TextChunk(_) }

  private def foldedString( texts : List[ Chunk ] ) : String =
    ( "" /: texts )( (current, text) => current + text.content )
}

case class FencedChunk(val content: String, language: Option[String])
extends Chunk {
  def appendNewBlock( list : collection.mutable.ListBuffer[Block],
                      remaining : List[ (Chunk, Seq[Span], Position) ],
                      spans : Seq[Span], position : Position,
                      discounter : Discounter ) {
    list += FencedCodeBlock(Text(content), position, language)
  }
}

case class FencedCodeBlock(text: Text, position: Position, 
                           language: Option[String]) extends Block