scala.tools.nsc.interpreter.ConsoleReaderHelper.scala Maven / Gradle / Ivy
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Compiler for the SubScript extension of the Scala Programming Language
/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Paul Phillips
*/
package scala.tools.nsc
package interpreter
import jline.console.{ ConsoleReader, CursorBuffer }
trait ConsoleReaderHelper { _: ConsoleReader with Tabulator =>
def isAcross: Boolean
def terminal = getTerminal()
def width = terminal.getWidth()
def height = terminal.getHeight()
def readOneKey(prompt: String): Int
def eraseLine(): Unit
val marginSize = 3
private def morePrompt = "--More--"
private def emulateMore(): Int = {
val key = readOneKey(morePrompt)
try key match {
case '\r' | '\n' => 1
case 'q' => -1
case _ => height - 1
}
finally {
eraseLine()
// TODO: still not quite managing to erase --More-- and get
// back to a scala prompt without another keypress.
if (key == 'q') {
putString(getPrompt())
redrawLine()
flush()
}
}
}
override def printColumns(items: JCollection[_ <: CharSequence]): Unit =
printColumns_(items: List[String])
private def printColumns_(items: List[String]): Unit = if (items exists (_ != "")) {
val grouped = tabulate(items)
var linesLeft = if (isPaginationEnabled()) height - 1 else Int.MaxValue
grouped foreach { xs =>
println(xs.mkString)
linesLeft -= 1
if (linesLeft <= 0) {
linesLeft = emulateMore()
if (linesLeft < 0)
return
}
}
}
}
trait Tabulator {
def isAcross: Boolean
def width: Int
def marginSize: Int
protected def fits(items: Seq[String], width: Int): Boolean = (
(items map (_.length)).sum + (items.length - 1) * marginSize < width
)
def tabulate(items: Seq[String]): Seq[Seq[String]] = (
if (fits(items, width)) Seq(Seq(items mkString " " * marginSize))
else printMultiLineColumns(items)
)
protected def columnize(ss: Seq[String]): Seq[Seq[String]] = ss map (s => Seq(s))
protected def printMultiLineColumns(items: Seq[String]): Seq[Seq[String]] = {
import SimpleMath._
val longest = (items map (_.length)).max
val columnWidth = longest + marginSize
val maxcols = (
if (columnWidth >= width) 1
else 1 max (width / columnWidth) // make sure it doesn't divide to 0
)
val nrows = items.size /% maxcols
val ncols = items.size /% nrows
val groupSize = ncols
val padded = items map (s"%-${columnWidth}s" format _)
val xwise = isAcross || ncols >= items.length
val grouped: Seq[Seq[String]] =
if (groupSize == 1) columnize(items)
else if (xwise) (padded grouped groupSize).toSeq
else {
val h = 1 max padded.size /% groupSize
val cols = (padded grouped h).toList
for (i <- 0 until h) yield
for (j <- 0 until groupSize) yield
if (i < cols(j).size) cols(j)(i) else ""
}
grouped
}
}
/** Adjust the column width and number of columns to minimize the row count. */
trait VariColumnTabulator extends Tabulator {
override protected def printMultiLineColumns(items: Seq[String]): Seq[Seq[String]] = {
import SimpleMath._
val longest = (items map (_.length)).max
val shortest = (items map (_.length)).min
val fattest = longest + marginSize
val skinny = shortest + marginSize
// given ncols, calculate nrows and a list of column widths, or none if not possible
// if ncols > items.size, then columnWidths.size == items.size
def layout(ncols: Int): Option[(Int, Seq[Int], Seq[Seq[String]])] = {
val nrows = items.size /% ncols
val xwise = isAcross || ncols >= items.length
def maxima(sss: Seq[Seq[String]]) =
(0 until (ncols min items.size)) map (i => (sss map (ss => ss(i).length)).max)
def resulting(rows: Seq[Seq[String]]) = {
val columnWidths = maxima(rows) map (_ + marginSize)
val linelen = columnWidths.sum
if (linelen <= width) Some((nrows, columnWidths, rows))
else None
}
if (ncols == 1) resulting(columnize(items))
else if (xwise) resulting((items grouped ncols).toSeq)
else {
val cols = (items grouped nrows).toList
val rows = for (i <- 0 until nrows) yield
for (j <- 0 until ncols) yield
if (j < cols.size && i < cols(j).size) cols(j)(i) else ""
resulting(rows)
}
}
if (fattest >= width) {
columnize(items)
} else {
// if every col is widest, we have at least this many cols
val mincols = 1 max (width / fattest)
// if every other col is skinniest, we have at most this many cols
val maxcols = 1 + ((width - fattest) / skinny)
val possibles = (mincols to maxcols).map(n => layout(n)).flatten
val minrows = (possibles map (_._1)).min
// select the min ncols that results in minrows
val (_, columnWidths, sss) = (possibles find (_._1 == minrows)).get
// format to column width
sss map (ss => ss.zipWithIndex map {
case (s, i) => s"%-${columnWidths(i)}s" format s
})
}
}
}
private[interpreter] object SimpleMath {
implicit class DivRem(private val i: Int) extends AnyVal {
/** i/n + if (i % n != 0) 1 else 0 */
def /%(n: Int): Int = (i + n - 1) / n
}
}