feat: implements error messages for DuplicateDeclaration and UndefinedIdentifier errors

src/main/wacc/Error.scala

@@ -12,3 +12,30 @@ enum Error {
   case TypeMismatch(pos: Position, expected: SemType, got: SemType, msg: String)
   case InternalError(pos: Position, msg: String)
 }
+
+def printError(error: Error)(using errorContent: String): Unit = {
+  println("Semantic error:")
+  error match {
+    case Error.DuplicateDeclaration(ident) =>
+      println(
+        s"Duplicate declaration of identifier ${ident.v} at line: ${ident.getPosition.line} column: ${ident.getPosition.column}"
+      )
+      highlight(ident.getPosition.line, ident.getPosition.column, ident.v.length)
+    case Error.UndefinedIdentifier(ident, identType) =>
+      println(
+        s"Undefined ${identType.toString.toLowerCase} ${ident.v} at line: ${ident.getPosition.line} column: ${ident.getPosition.column}"
+      )
+      highlight(ident.getPosition.line, ident.getPosition.column, ident.v.length)
+    case Error.FunctionParamsMismatch(ident, expected, got) =>
+      println(s"Function ${ident.v} expects $expected parameters, got $got")
+    case Error.TypeMismatch(expected, got) =>
+      println(s"Type mismatch: expected $expected, got $got")
+  }
+
+}
+
+def highlight(line: Int, column: Int, size: Int)(using errorContent: String): Unit = {
+  val lines = errorContent.split("\n")
+  val linePointer = " " * (column) + ("^" * (size)) + "\n"
+  println(s">${lines(line - 2)}\n>${lines(line - 1)}\n$linePointer>${lines(line)}")
+}

src/main/wacc/Main.scala

@@ -38,7 +38,8 @@ def compile(contents: String): Int = {
       given ctx: typeChecker.TypeCheckerCtx = typeChecker.TypeCheckerCtx(names, errors)
       typeChecker.check(prog)
       if (errors.result.nonEmpty) {
-        errors.result.foreach(println)
+        given errorContent: String = contents
+        errors.result.foreach(printError)
         200
       } else 0
     case Failure(msg) =>