improve parsing

Author: Quafadas

scautable/src/csvParser.scala

@@ -32,10 +32,34 @@ private[scautable] object CSVParser:
             // End of quoted section
             inQuotes = false
 
-        case '\\' if inQuotes && i + 1 < line.length && line.charAt(i + 1) == quote =>
-          // Handle backslash-escaped quotes
-          cellBuffer.append(quote)
-          i += 1 // Skip the escaped quote
+        case '\\' if inQuotes && i + 1 < line.length =>
+          // Handle backslash-escaped characters
+          val nextChar = line.charAt(i + 1)
+          nextChar match
+            case 'n' =>
+              // Escaped linefeed
+              cellBuffer.append('\n')
+              i += 1
+            case 'r' =>
+              // Escaped carriage return
+              cellBuffer.append('\r')
+              i += 1
+            case '\\' =>
+              // Escaped backslash
+              cellBuffer.append('\\')
+              i += 1
+            case `delimiter` =>
+              // Escaped delimiter
+              cellBuffer.append(delimiter)
+              i += 1
+            case `quote` =>
+              // Escaped quote character
+              cellBuffer.append(quote)
+              i += 1
+            case _ =>
+              // Unknown escape sequence - treat backslash literally
+              cellBuffer.append('\\')
+              // Don't increment i, let the next character be processed normally
 
         case `delimiter` if !inQuotes =>
           // Delimiter outside quotes ends the current cell

scautable/test/src/io/github/quafadas/scautable/CSVParserSuite.scala

@@ -116,3 +116,52 @@ class CSVParserSuite extends FunSuite:
     val result = CSVParser.parseLine(line)
     assertEquals(result, List("", "field2", "field3"))
   }
+
+  // Tests for full escape character support (ESCAPE specification)
+  test("parseLine should handle backslash-escaped linefeeds") {
+    val line = "field1,\"field2 with \\n newline\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 with \n newline", "field3"))
+  }
+
+  test("parseLine should handle backslash-escaped carriage returns") {
+    val line = "field1,\"field2 with \\r return\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 with \r return", "field3"))
+  }
+
+  test("parseLine should handle backslash-escaped delimiters") {
+    val line = "field1,\"field2 with \\, comma\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 with , comma", "field3"))
+  }
+
+  test("parseLine should handle backslash-escaped backslashes") {
+    val line = "field1,\"field2 with \\\\ backslash\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 with \\ backslash", "field3"))
+  }
+
+  test("parseLine should handle custom delimiter with backslash-escaped delimiter") {
+    val line = "field1;\"field2 with \\; semicolon\";field3"
+    val result = CSVParser.parseLine(line, delimiter = ';')
+    assertEquals(result, List("field1", "field2 with ; semicolon", "field3"))
+  }
+
+  test("parseLine should handle multiple escape sequences in one field") {
+    val line = "field1,\"field2 with \\n\\r\\, and \\\" escapes\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 with \n\r, and \" escapes", "field3"))
+  }
+
+  test("parseLine should handle backslash at end of field (not escaping anything)") {
+    val line = "field1,\"field2 ends with \\\\\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 ends with \\", "field3"))
+  }
+
+  test("parseLine should handle invalid escape sequences by treating backslash literally") {
+    val line = "field1,\"field2 with \\z invalid escape\",field3"
+    val result = CSVParser.parseLine(line)
+    assertEquals(result, List("field1", "field2 with \\z invalid escape", "field3"))
+  }