Fix AdvanceNoNewLines not updating column count.

src/Parlot/Cursor.cs

@@ -118,18 +118,21 @@ public void Advance(int count)
         public void AdvanceNoNewLines(int offset)
         {
             var newOffset = _offset + offset;
+            var length = _textLength - 1;
 
             // Detect if the cursor will be over Eof
-            if (newOffset > _textLength - 1)
+            if (newOffset > length)
             {
                 Eof = true;
+                _column += newOffset - length;
                 _offset = _textLength;
                 _current = NullChar;
                 return;
             }
 
             _current = _buffer[newOffset];
             _offset = newOffset;
+            _column += offset;
         }
 
         /// <summary>

test/Parlot.Tests/CursorTests.cs

@@ -165,6 +165,63 @@ public void AdvanceShouldStopAtEof()
             Assert.Equal(1, c.Position.Line);
         }
 
+        [Fact]
+        public void AdvanceNoNewLinesShouldCountColumns()
+        {
+            var c = new Cursor("123456789");
+
+            Assert.Equal('1', c.Current);
+            Assert.Equal(0, c.Position.Offset);
+            Assert.Equal(1, c.Position.Column);
+            Assert.Equal(1, c.Position.Line);
+
+            c.AdvanceNoNewLines(4);
+
+            Assert.Equal('5', c.Current);
+            Assert.Equal(4, c.Position.Offset);
+            Assert.Equal(5, c.Position.Column);
+            Assert.Equal(1, c.Position.Line);
+
+            c.AdvanceNoNewLines(4);
+
+            Assert.Equal('9', c.Current);
+            Assert.Equal(8, c.Position.Offset);
+            Assert.Equal(9, c.Position.Column);
+            Assert.Equal(1, c.Position.Line);
+
+            c.AdvanceNoNewLines(1);
+
+            Assert.Equal(Cursor.NullChar, c.Current);
+            Assert.Equal(9, c.Position.Offset);
+            Assert.Equal(10, c.Position.Column);
+            Assert.Equal(1, c.Position.Line);
+        }
+
+        [Fact]
+        public void AdvanceNoNewLinesShouldStopAtEof()
+        {
+            var c = new Cursor("1234\n5678");
+
+            Assert.Equal('1', c.Current);
+            Assert.Equal(0, c.Position.Offset);
+            Assert.Equal(1, c.Position.Column);
+            Assert.Equal(1, c.Position.Line);
+
+            c.Advance(5);
+
+            Assert.Equal('5', c.Current);
+            Assert.Equal(5, c.Position.Offset);
+            Assert.Equal(1, c.Position.Column);
+            Assert.Equal(2, c.Position.Line);
+
+            c.AdvanceNoNewLines(6);
+
+            Assert.Equal(Cursor.NullChar, c.Current);
+            Assert.Equal(9, c.Position.Offset);
+            Assert.Equal(4, c.Position.Column);
+            Assert.Equal(2, c.Position.Line);
+        }
+
         [Fact]
         public void ResetPositionShouldMoveToEof()
         {