com.github.andyglow.tree.Result.scala Maven / Gradle / Ivy

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package com.github.andyglow.tree

import scala.annotation.tailrec

/** The intermediate return type of the pretty-print system: provides an iterator which produces the actual string output, as well as metadata around that output that is only available after the
  * iterator is exhausted
  */
class Result(val iter: Iterator[String], completedLineCount0: => Int, lastLineLength0: => Int) {
  lazy val completedLineCount = {
    require(iter.isEmpty)
    completedLineCount0
  }
  lazy val lastLineLength = {
    require(iter.isEmpty)
    lastLineLength0
  }
  def flatMap(f: (Int, Int) => Result): Result = {
    var newCompletedLineCount = 0
    var newLastLineLength     = 0

    val mergedIterator = Util.concat(
      () => iter,
      () => {
        require(!iter.hasNext)
        val newResult = f(completedLineCount, lastLineLength0)
        newResult.iter.map { x =>
          if (!newResult.iter.hasNext) {
            newCompletedLineCount = newResult.completedLineCount
            newLastLineLength = newResult.lastLineLength
          }
          x
        }
      }
    )
    new Result(
      mergedIterator,
      newCompletedLineCount + completedLineCount,
      if (newCompletedLineCount > 0) newLastLineLength
      else newLastLineLength + lastLineLength
    )

  }
}

object Result {
  def fromString(s: => String) = {
    lazy val lines = s.linesIterator.toArray
    new Result(Iterator(s), lines.length - 1, lines.last.length)
  }
}