refactor: consistent error handling in Main.scala

src/main/wacc/frontend/Error.scala

@@ -3,6 +3,9 @@ package wacc
 import wacc.ast.Position
 import wacc.types._
 
+private val SYNTAX_ERROR = 100
+private val SEMANTIC_ERROR = 200
+
 /** Error types for semantic errors
   */
 enum Error {
@@ -14,6 +17,15 @@ enum Error {
   case SemanticError(pos: Position, msg: String)
   case TypeMismatch(pos: Position, expected: SemType, got: SemType, msg: String)
   case InternalError(pos: Position, msg: String)
+
+  case SyntaxError(msg: String)
+}
+
+extension (e: Error) {
+  def exitCode: Int = e match {
+    case Error.SyntaxError(_) => SYNTAX_ERROR
+    case _                    => SEMANTIC_ERROR
+  }
 }
 
 /** Function to handle printing the details of a given semantic error
@@ -25,7 +37,6 @@ enum Error {
   */
 def formatError(error: Error)(using errorContent: String): String = {
   val sb = new StringBuilder()
-  sb.append("Semantic error:\n")
 
   /** Function to format the position of an error
     *
@@ -55,6 +66,13 @@ def formatError(error: Error)(using errorContent: String): String = {
     )
   }
 
+  error match {
+    case Error.SyntaxError(_) =>
+      sb.append("Syntax error:\n")
+    case _ =>
+      sb.append("Semantic error:\n")
+  }
+
   error match {
     case Error.DuplicateDeclaration(ident) =>
       formatPosition(ident.pos)
@@ -87,6 +105,9 @@ def formatError(error: Error)(using errorContent: String): String = {
       formatPosition(pos)
       sb.append(s"Internal error: $msg")
       formatHighlight(pos, 1)
+    case Error.SyntaxError(msg) =>
+      sb.append(msg)
+      sb.append("\n")
   }
 
   sb.toString()