Refactored Printers, Showable and Text into new package dotc.printing.

1 files changed, 153 insertions, 0 deletions

diff --git a/src/dotty/tools/dotc/printing/Texts.scala b/src/dotty/tools/dotc/printing/Texts.scala
new file mode 100644
index 000000000..2ff4edc9a
--- /dev/null
+++ b/src/dotty/tools/dotc/printing/Texts.scala
@@ -0,0 +1,153 @@
+package dotty.tools.dotc
+package printing
+
+object Texts {
+
+  abstract class Text {
+
+    protected def indentMargin = 2
+
+    def relems: List[Text]
+
+    def isEmpty: Boolean = this match {
+      case Str(s) => s.isEmpty
+      case Fluid(relems) => relems forall (_.isEmpty)
+      case Vertical(relems) => relems.isEmpty
+    }
+
+    def isVertical = isInstanceOf[Vertical]
+    def isClosed = isVertical || isInstanceOf[Closed]
+    def isFluid = isInstanceOf[Fluid]
+    def isSplittable = isFluid && !isClosed
+
+    def close = new Closed(relems)
+
+    def remaining(width: Int): Int = this match {
+      case Str(s) =>
+        width - s.length
+      case Fluid(Nil) =>
+        width
+      case Fluid(last :: prevs) =>
+        val r = last remaining width
+        if (r < 0) r else Fluid(prevs) remaining r
+      case Vertical(_) =>
+        -1
+    }
+
+    def lastLine: String = this match {
+      case Str(s) => s
+      case _ => relems.head.lastLine
+    }
+
+    def appendToLastLine(that: Text): Text = that match {
+      case Str(s2) =>
+        this match {
+          case Str(s1) => Str(s1 + s2)
+          case Fluid(Str(s1) :: prev) => Fluid(Str(s1 + s2) :: prev)
+          case Fluid(relems) => Fluid(that :: relems)
+        }
+      case Fluid(relems) =>
+        (this /: relems.reverse)(_ appendToLastLine _)
+    }
+
+    private def appendIndented(that: Text)(width: Int): Text =
+      Vertical(that.layout(width - indentMargin).indented :: this.relems)
+
+    private def append(width: Int)(that: Text): Text = {
+      if (this.isEmpty) that.layout(width)
+      else if (that.isEmpty) this
+      else if (that.isVertical) appendIndented(that)(width)
+      else if (this.isVertical) Fluid(that.layout(width) :: this.relems)
+      else if (that.remaining(width - lastLine.length) >= 0) appendToLastLine(that)
+      else if (that.isSplittable) (this /: that.relems.reverse)(_.append(width)(_))
+      else appendIndented(that)(width)
+    }
+
+    def layout(width: Int): Text = this match {
+      case Str(_) =>
+        this
+      case Fluid(relems) =>
+        ((Str(""): Text) /: relems.reverse)(_.append(width)(_))
+      case Vertical(relems) =>
+        Vertical(relems map (_ layout width))
+    }
+
+    def map(f: String => String): Text = this match {
+      case Str(s) => Str(f(s))
+      case Fluid(relems) => Fluid(relems map (_ map f))
+      case Vertical(relems) => Vertical(relems map (_ map f))
+    }
+
+    def stripPrefix(pre: String): Text = this match {
+      case Str(s) =>
+        if (s.startsWith(pre)) s drop pre.length else s
+      case Fluid(relems) =>
+        val elems = relems.reverse
+        val head = elems.head.stripPrefix(pre)
+        if (head eq elems.head) this else Fluid((head :: elems.tail).reverse)
+      case Vertical(relems) =>
+        val elems = relems.reverse
+        val head = elems.head.stripPrefix(pre)
+        if (head eq elems.head) this else Vertical((head :: elems.tail).reverse)
+    }
+
+    private def indented: Text = this match {
+      case Str(s) => Str((" " * indentMargin) + s)
+      case Fluid(relems) => Fluid(relems map (_.indented))
+      case Vertical(relems) => Vertical(relems map (_.indented))
+    }
+
+    def print(sb: StringBuilder): Unit = this match {
+      case Str(s) =>
+        sb.append(s)
+      case _ =>
+        var follow = false
+        for (elem <- relems.reverse) {
+          if (follow) sb.append("\n")
+          elem.print(sb)
+          follow = true
+        }
+    }
+
+    def mkString(width: Int): String = {
+      val sb = new StringBuilder
+      layout(width).print(sb)
+      sb.toString
+    }
+
+    def ~ (that: Text) =
+      if (this.isEmpty) that
+      else if (that.isEmpty) this
+      else Fluid(that :: this :: Nil)
+
+    def ~~ (that: Text) =
+      if (this.isEmpty) that
+      else if (that.isEmpty) this
+      else Fluid(that :: Str(" ") :: this :: Nil)
+
+    def over (that: Text) =
+      if (this.isVertical) Vertical(that :: this.relems)
+      else Vertical(that :: this :: Nil)
+  }
+
+  object Text {
+    def apply(): Text = Str("")
+    def apply(xs: Traversable[Text], sep: String = " "): Text = {
+      val ys = xs filterNot (_.isEmpty)
+      if (ys.isEmpty) Str("")
+      else ys reduce (_ ~ sep ~ _)
+    }
+    def lines(xs: Traversable[Text]) = Vertical(xs.toList.reverse)
+  }
+
+  case class Str(s: String) extends Text {
+    override def relems: List[Text] = List(this)
+  }
+
+  case class Vertical(relems: List[Text]) extends Text
+  case class Fluid(relems: List[Text]) extends Text
+
+  class Closed(relems: List[Text]) extends Fluid(relems)
+
+  implicit def stringToText(s: String): Text = Str(s)
+}
\ No newline at end of file