Message rendering: colorize positional splice, then split

3 files changed, 54 insertions, 17 deletions

diff --git a/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala b/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala
index 86f34e64d..e20f846ac 100644
--- a/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala
+++ b/compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala
@@ -6,6 +6,7 @@ import parsing.Tokens._
 import scala.annotation.switch
 import scala.collection.mutable.StringBuilder
 import core.Contexts.Context
+import util.Chars.{ LF, FF, CR, SU }
 import Highlighting.{Highlight, HighlightBuffer}
 
 /** This object provides functions for syntax highlighting in the REPL */
@@ -26,7 +27,7 @@ object SyntaxHighlighting {
   private def valDef(str: String) = ValDefColor + str + NoColor
   private def operator(str: String) = TypeColor + str + NoColor
   private def annotation(str: String) =
-    if (str.trim == "@") str else AnnotationColor + str + NoColor
+    if (str.trim == "@") str else { AnnotationColor + str + NoColor }
   private val tripleQs = Console.RED_B + "???" + NoColor
 
   private val keywords: Seq[String] = for {
@@ -152,7 +153,11 @@ object SyntaxHighlighting {
       var open = 1
       while (open > 0 && remaining.nonEmpty) {
         curr = takeChar()
-        newBuf += curr
+        if (curr == '@') {
+          appendWhile('@', !typeEnders.contains(_), annotation)
+          newBuf append CommentColor
+        }
+        else newBuf += curr
 
         if (curr == '*' && remaining.nonEmpty) {
           curr = takeChar()
@@ -163,6 +168,11 @@ object SyntaxHighlighting {
           newBuf += curr
           if (curr == '*') open += 1
         }
+
+        (curr: @switch) match {
+          case LF | FF | CR | SU => newBuf append CommentColor
+          case _ => ()
+        }
       }
       prev = curr
       newBuf append NoColor
@@ -236,6 +246,11 @@ object SyntaxHighlighting {
           newBuf += curr
           closing = 0
         }
+
+        (curr: @switch) match {
+          case LF | FF | CR | SU => newBuf append LiteralColor
+          case _ => ()
+        }
       }
       newBuf append NoColor
       prev = curr
diff --git a/compiler/src/dotty/tools/dotc/reporting/MessageRendering.scala b/compiler/src/dotty/tools/dotc/reporting/MessageRendering.scala
index 190445d60..17eb8d39b 100644
--- a/compiler/src/dotty/tools/dotc/reporting/MessageRendering.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/MessageRendering.scala
@@ -5,9 +5,12 @@ package reporting
 import core.Contexts.Context
 import core.Decorators._
 import printing.Highlighting.{Blue, Red}
+import printing.SyntaxHighlighting
 import diagnostic.{ErrorMessageID, Message, MessageContainer, NoExplanation}
 import diagnostic.messages._
 import util.SourcePosition
+import util.Chars.{ LF, CR, FF, SU }
+import scala.annotation.switch
 
 import scala.collection.mutable
 
@@ -38,20 +41,37 @@ trait MessageRendering {
     */
   def sourceLines(pos: SourcePosition)(implicit ctx: Context): (List[String], List[String], Int) = {
     var maxLen = Int.MinValue
-    def render(xs: List[Int]) =
-      xs.map(pos.source.offsetToLine(_))
-        .map { lineNbr =>
-          val prefix = s"${lineNbr + 1} |"
-          maxLen = math.max(maxLen, prefix.length)
-          (prefix, pos.lineContent(lineNbr).stripLineEnd)
-        }
-        .map { case (prefix, line) =>
-          val lnum = Red(" " * math.max(0, maxLen - prefix.length) + prefix)
-          hl"$lnum$line"
-        }
+    def render(offsetAndLine: (Int, String)): String = {
+      val (offset, line) = offsetAndLine
+      val lineNbr = pos.source.offsetToLine(offset)
+      val prefix = s"${lineNbr + 1} |"
+      maxLen = math.max(maxLen, prefix.length)
+      val lnum = Red(" " * math.max(0, maxLen - prefix.length) + prefix).show
+      lnum + line.stripLineEnd
+    }
+
+    def linesFrom(arr: Array[Char]): List[String] = {
+      def pred(c: Char) = (c: @switch) match {
+        case LF | CR | FF | SU => true
+        case _ => false
+      }
+      val (line, rest0) = arr.span(!pred(_))
+      val (_, rest) = rest0.span(pred)
+      new String(line) :: { if (rest.isEmpty) Nil else linesFrom(rest) }
+    }
 
+    val syntax =
+      if (ctx.settings.color.value != "never")
+        SyntaxHighlighting(pos.linesSlice).toArray
+      else pos.linesSlice
+    val lines = linesFrom(syntax)
     val (before, after) = pos.beforeAndAfterPoint
-    (render(before), render(after), maxLen)
+
+    (
+      before.zip(lines).map(render),
+      after.zip(lines.drop(before.length)).map(render),
+      maxLen
+    )
   }
 
   /** The column markers aligned under the error */
diff --git a/compiler/src/dotty/tools/dotc/util/SourcePosition.scala b/compiler/src/dotty/tools/dotc/util/SourcePosition.scala
index aad4995d8..be5c46995 100644
--- a/compiler/src/dotty/tools/dotc/util/SourcePosition.scala
+++ b/compiler/src/dotty/tools/dotc/util/SourcePosition.scala
@@ -12,9 +12,14 @@ extends interfaces.SourcePosition {
   def lineContent: String = source.lineContent(point)
 
   def point: Int = pos.point
+
   /** The line of the position, starting at 0 */
   def line: Int = source.offsetToLine(point)
 
+  /** Extracts the lines from the underlying source file as `Array[Char]`*/
+  def linesSlice: Array[Char] =
+    source.content.slice(source.startOfLine(start), source.nextLine(end))
+
   /** The lines of the position */
   def lines: List[Int] =
     List.range(source.offsetToLine(start), source.offsetToLine(end + 1)) match {
@@ -25,9 +30,6 @@ extends interfaces.SourcePosition {
   def lineOffsets: List[Int] =
     lines.map(source.lineToOffset(_))
 
-  def lineContent(lineNumber: Int): String =
-    source.lineContent(source.lineToOffset(lineNumber))
-
   def beforeAndAfterPoint: (List[Int], List[Int]) =
     lineOffsets.partition(_ <= point)