Implement decodeIllegalChars

Author: nicolasstucki

compiler/src/dotty/tools/dotc/interactive/Completion.scala

@@ -1,5 +1,7 @@
 package dotty.tools.dotc.interactive
 
+import java.nio.charset.Charset
+
 import dotty.tools.dotc.ast.Trees._
 import dotty.tools.dotc.config.Printers.interactiv
 import dotty.tools.dotc.core.Contexts.{Context, NoContext}
@@ -10,13 +12,13 @@ import dotty.tools.dotc.core.Flags._
 import dotty.tools.dotc.core.Names.{Name, TermName}
 import dotty.tools.dotc.core.NameKinds.SimpleNameKind
 import dotty.tools.dotc.core.NameOps.NameDecorator
-import dotty.tools.dotc.core.Symbols.{defn, NoSymbol, Symbol}
+import dotty.tools.dotc.core.Symbols.{NoSymbol, Symbol, defn}
 import dotty.tools.dotc.core.Scopes
 import dotty.tools.dotc.core.StdNames.{nme, tpnme}
 import dotty.tools.dotc.core.TypeError
-import dotty.tools.dotc.core.Types.{NameFilter, NamedType, Type, NoType}
+import dotty.tools.dotc.core.Types.{NameFilter, NamedType, NoType, Type}
 import dotty.tools.dotc.printing.Texts._
-import dotty.tools.dotc.util.{NoSourcePosition, SourcePosition}
+import dotty.tools.dotc.util.{NameTransformer, NoSourcePosition, SourcePosition}
 
 import scala.collection.mutable
 
@@ -150,8 +152,7 @@ object Completion {
       nameToSymbols.map { case (name, symbols) =>
         val typesFirst = symbols.sortWith((s1, s2) => s1.isType && !s2.isType)
         val desc = description(typesFirst)
-        val strName = name.toString
-        val label = if (strName == "$u2192") "→" else strName // TODO fix name.decode and use it
+        val label = NameTransformer.decodeIllegalChars(name.toString)
         Completion(label, desc, typesFirst)
       }
     }

compiler/src/dotty/tools/dotc/util/NameTransformer.scala

@@ -55,6 +55,29 @@ object NameTransformer {
     else name
   }
 
+  /** Decode expanded characters starting with `$u`, followed by the character's unicode expansion. */
+  def decodeIllegalChars(name: String): String = {
+    if (name.contains("$u")) {
+      val sb = new mutable.StringBuilder()
+      var i = 0
+      while (i < name.length - 5) {
+        if (name(i) == '$' && name(i + 1) == 'u') {
+          sb.append(Integer.valueOf(name.substring(i + 2, i + 6), 16).toChar)
+          i += 6
+        } else {
+          sb.append(name(i))
+          i += 1
+        }
+      }
+      while (i < name.length) {
+        sb.append(name(i))
+        i += 1
+      }
+      sb.result()
+    }
+    else name
+  }
+
   /** Replace operator symbols by corresponding expansion strings.
    *
    *  @param name the string to encode