Fix #3814 Correct highlighting issues in REPL

Correct highlighting after "|", ":", "&" characters
and after "case", "val", "val" when using extractors.

Author: benkobalog

compiler/src/dotty/tools/dotc/printing/SyntaxHighlighting.scala

@@ -42,8 +42,8 @@ object SyntaxHighlighting {
     'q' :: 'r' :: 's' :: 't' :: 'u' :: 'v' :: 'w' :: 'x' :: 'y' :: 'z' :: Nil
 
   private val typeEnders =
-   '{'  :: '}' :: ')' :: '(' :: '[' :: ']' :: '=' :: ' ' :: ',' :: '.' ::
-   '\n' :: Nil
+   '{'  :: '}' :: ')' :: '(' :: '[' :: ']' :: '=' :: ' ' :: ',' :: '.' :: '|' ::
+   '&' :: '\n' :: Nil
 
   def apply(chars: Iterable[Char]): Iterable[Char] = {
     var prev: Char = 0
@@ -53,7 +53,8 @@ object SyntaxHighlighting {
 
     @inline def keywordStart =
       prev == 0    || prev == ' ' || prev == '{' || prev == '(' ||
-      prev == '\n' || prev == '[' || prev == ','
+      prev == '\n' || prev == '[' || prev == ',' || prev == ':' ||
+      prev == '|'  || prev == '&'
 
     @inline def numberStart(c: Char) =
       c.isDigit && (!prev.isLetter || prev == '.' || prev == ' ' || prev == '(' || prev == '\u0000')
@@ -286,9 +287,20 @@ object SyntaxHighlighting {
         case '@' => true
         case ',' => true
         case '.' => true
+        case ',' => true
+        case ')' => true
         case _ => false
       }
 
+      def shouldUpdateLastToken(currentPotentialToken: String): Boolean =
+        (lastToken, currentPotentialToken) match {
+          case (_, ("var" | "val" | "def" | "case")) => true
+          case (("val" | "var"), "=") => true
+          case ("case", ("=>" | "class" | "object")) => true
+          case ("def", _) => true
+          case _ => false
+        }
+
       while (remaining.nonEmpty && !delim(curr)) {
         curr = takeChar()
         if (!delim(curr)) sb += curr
@@ -298,12 +310,13 @@ object SyntaxHighlighting {
       val toAdd  =
         if (shouldHL(str))
           highlight(str)
-        else if (("var" :: "val" :: "def" :: "case" :: Nil).contains(lastToken))
+        else if (("var" :: "val" :: "def" :: "case" :: Nil).contains(lastToken) &&
+          !List("=", "=>").contains(str))
           valDef(str)
         else str
       val suffix = if (delim(curr)) s"$curr" else ""
       newBuf append (toAdd + suffix)
-      lastToken = str
+      if (shouldUpdateLastToken(str)) lastToken = str
       prev = curr
     }
 

compiler/test-resources/printing/defs

@@ -0,0 +1,31 @@
+package test
+
+object A {
+ val a = 123
+ var b = 123 /*Int*/
+ var c = "123" // String
+ var d: Int = 123
+ var e:Int = 123;e
+ e
+ print(a)
+ 123;123
+ def f = 123
+ def f1(x: Int) = 123
+ def f2[T](x: T) = { 123 }
+}
+result:
+package test
+
+object A {
+ val a = 123
+ var b = 123 /*Int*/
+ var c = "123" // String
+ var d: Int = 123
+ var e:Int = 123;e
+ e
+ print(a)
+ 123;123
+ def f = 123
+ def f1(x: Int) = 123
+ def f2[T](x: T) = { 123 }
+}

compiler/test-resources/printing/patternMatching

@@ -0,0 +1,29 @@
+val aFruit: Fruit = Apple("red", 123)
+
+val Apple(color, weight) = aFruit
+
+sealed trait Fruit
+case class Apple(color: String, weight: Double) extends Fruit
+case class Orange(weight: Double) extends Fruit
+case class Melon(weight: Double) extends Fruit
+
+aFruit match {
+  case Apple(_, weight) => println(s"apple: $weight kgs")
+  case o: Orange => println(s"orange ${o.weight} kgs")
+  case m @ Melon(weight) => println(s"melon: ${m.weight} kgs")
+}
+result:
+val aFruit: Fruit = Apple("red", 123)
+
+val Apple(color, weight) = aFruit
+
+sealed trait Fruit
+case class Apple(color: String, weight: Double) extends Fruit
+case class Orange(weight: Double) extends Fruit
+case class Melon(weight: Double) extends Fruit
+
+aFruit match {
+  case Apple(_, weight) => println(s"apple: $weight kgs")
+  case o: Orange => println(s"orange ${o.weight} kgs")
+  case m @ Melon(weight) => println(s"melon: ${m.weight} kgs")
+}

compiler/test-resources/printing/unionAndIntersectionTypes

@@ -0,0 +1,15 @@
+type A = String|Int| Long
+type B = String |Int| Long
+type C = String | Int | Long
+type D = String&Int& Long
+type E = String &Int& Long
+type F = String & Int & Long
+fn[String|Char](input)
+result:
+type A = String|Int| Long
+type B = String |Int| Long
+type C = String | Int | Long
+type D = String&Int& Long
+type E = String &Int& Long
+type F = String & Int & Long
+fn[String|Char](input)

compiler/test/dotty/tools/dotc/printing/SyntaxHighlightingTests.scala

@@ -0,0 +1,36 @@
+package dotty.tools.dotc.printing
+
+import dotty.tools.io.JFile
+import org.junit.Test
+import org.junit.Assert.fail
+
+import scala.io.Source
+
+/** Runs all tests contained in `compiler/test-resources/printing/`
+  * To check test cases, you can use "cat" or "less -r" from bash*/
+class SyntaxHighlightingTests {
+
+  private def scripts(path: String): Array[JFile] = {
+    val dir = new JFile(getClass.getResource(path).getPath)
+    assert(dir.exists && dir.isDirectory, "Couldn't load scripts dir")
+    dir.listFiles
+  }
+
+  private def testFile(f: JFile): Unit = {
+    val linesIt = Source.fromFile(f).getLines()
+    val input = linesIt.takeWhile(_ != "result:").mkString("\n")
+    val expectedOutput = linesIt.mkString("\n")
+    val actualOutput = SyntaxHighlighting(input).mkString
+
+    if (expectedOutput != actualOutput) {
+      println("Expected output:")
+      println(expectedOutput)
+      println("Actual output:")
+      println(actualOutput)
+
+      fail(s"Error in file $f, expected output did not match actual")
+    }
+  }
+
+  @Test def syntaxHighlight = scripts("/printing").foreach(testFile)
+}