From a2c81883f49e90fb077d7556f1a4d3e58f662363 Mon Sep 17 00:00:00 2001
From: Guy C <gc1523@ic.ac.uk>
Date: Thu, 6 Feb 2025 20:46:45 +0000
Subject: [PATCH] refactor: improvements to semantic error printing format

Co-authored by: al4423
---
 src/main/wacc/Error.scala | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/main/wacc/Error.scala b/src/main/wacc/Error.scala
index a90c340..87e0a35 100644
--- a/src/main/wacc/Error.scala
+++ b/src/main/wacc/Error.scala
@@ -20,12 +20,12 @@ def printError(error: Error)(using errorContent: String): Unit = {
       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)
+      highlight(ident)
     case Error.UndefinedIdentifier(ident, identType) =>
       println(
-        s"Undefined ${identType.toString.toLowerCase} ${ident.v} at line: ${ident.getPosition.line} column: ${ident.getPosition.column}"
+        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)
+      highlight(ident)
     case Error.FunctionParamsMismatch(ident, expected, got) =>
       println(s"Function ${ident.v} expects $expected parameters, got $got")
     case Error.TypeMismatch(expected, got) =>
@@ -34,8 +34,25 @@ def printError(error: Error)(using errorContent: String): Unit = {
 
 }
 
-def highlight(line: Int, column: Int, size: Int)(using errorContent: String): Unit = {
+def highlight(ident: ast.Ident)(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)}")
+
+  val preLine = if (ident.getPosition.line > 1) lines(ident.getPosition.line - 2) else ""
+  val midLine = lines(ident.getPosition.line - 1)
+  val postLine = lines(ident.getPosition.line)
+  val linePointer = " " * (ident.getPosition.column) + ("^" * (ident.v.length)) + "\n"
+
+  println(
+    s">$preLine\n>$midLine\n$linePointer>$postLine"
+  )
+
+  // var lines: Iterator[String] = errorContent.linesIterator
+
+  // lines = lines.drop(Math.max(0, ident.getPosition.line - 2))
+  // println(s">${lines.next()}")
+  // if (lines.hasNext)
+  //   println(s">${lines.next()}")
+  // println(" " * (ident.getPosition.column) + ("^" * (ident.v.length)))
+  // if(lines.hasNext)
+  //   println(s">${lines.next()}")
 }