Give position information on parser errors.

mcoblenz · Jan 21, 2020 · c21e62f · c21e62f
1 parent 20f4737
commit c21e62f
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/src/main/scala/edu/cmu/cs/obsidian/lexer/TokenReader.scala b/src/main/scala/edu/cmu/cs/obsidian/lexer/TokenReader.scala
@@ -4,7 +4,7 @@ import scala.util.parsing.input._
 
 class TokenReader(tokens : Seq[Token]) extends Reader[Token] {
     override def atEnd : Boolean = tokens.isEmpty
-    override def pos: Position = NoPosition
+    override def pos: Position = if (atEnd) NoPosition else first.pos
 
     override def first : Token = tokens.head
     override def rest : Reader[Token] = new TokenReader(tokens.tail)

diff --git a/src/main/scala/edu/cmu/cs/obsidian/parser/Parser.scala b/src/main/scala/edu/cmu/cs/obsidian/parser/Parser.scala
@@ -781,7 +781,7 @@ object Parser extends Parsers {
         val reader = new TokenReader(tokens)
         parseProgram(srcPath)(reader) match {
             case Success(result, _) => Right(result)
-            case Failure(msg , _) => Left(s"PARSER FAILURE: $msg")
+            case Failure(msg, reader) => Left(s"Parser failure at ${reader.pos}: $msg")
             case Error(msg , next) =>
                 if (next.atEnd) {
                     Left(s"Parser Error: $msg at end of file")