diff --git a/processor/processor.go b/processor/processor.go
index 1076cd0..88384b0 100644
--- a/processor/processor.go
+++ b/processor/processor.go
@@ -487,8 +487,8 @@ func EvalRegex(L *lua.LState) int {
 	evalRegexLogger := processorLogger.WithPrefix("evalRegex")
 	evalRegexLogger.Debug("Lua evalRegex function called")
 
-	input := L.ToString(1)
-	pattern := L.ToString(2)
+	pattern := L.ToString(1)
+	input := L.ToString(2)
 
 	evalRegexLogger.Debug("Pattern: %q, Input: %q", pattern, input)
 
@@ -496,6 +496,7 @@ func EvalRegex(L *lua.LState) int {
 	matches := re.FindStringSubmatch(input)
 
 	evalRegexLogger.Debug("Go regex matches: %v (count: %d)", matches, len(matches))
+	evalRegexLogger.Debug("Matches is nil: %t", matches == nil)
 
 	if len(matches) > 0 {
 		matchesTable := L.NewTable()
diff --git a/processor/processor_test.go b/processor/processor_test.go
index d4cbe67..8723b0d 100644
--- a/processor/processor_test.go
+++ b/processor/processor_test.go
@@ -21,7 +21,7 @@ func TestEvalRegex_CaptureGroupsReturned(t *testing.T) {
 
 	result := processor.EvalRegex(L)
 
-	assert.Equal(t, 0, result, "Expected return value to be 0")
+	assert.Equal(t, 1, result, "Expected return value to be 1 (one value pushed to Lua stack)")
 
 	out := L.Get(-1)
 	tbl, ok := out.(*lua.LTable)
@@ -35,26 +35,19 @@ func TestEvalRegex_CaptureGroupsReturned(t *testing.T) {
 	}
 }
 
-// Happy Path: Function returns an empty Lua table when regex pattern does not match input string.
-func TestEvalRegex_NoMatchReturnsEmptyTable(t *testing.T) {
+// Happy Path: Function returns nil when regex pattern does not match input string.
+func TestEvalRegex_NoMatchReturnsNil(t *testing.T) {
 	L := lua.NewState()
 	defer L.Close()
 	L.Push(lua.LString(`(foo)(bar)`))
 	L.Push(lua.LString("no-match-here"))
 
 	result := processor.EvalRegex(L)
-	assert.Equal(t, 0, result)
+	assert.Equal(t, 1, result, "Expected return value to be 1 (one value pushed to Lua stack)")
 
 	out := L.Get(-1)
-	tbl, ok := out.(*lua.LTable)
-	if !ok {
-		t.Fatalf("Expected Lua table, got %T", out)
-	}
-	count := 0
-	tbl.ForEach(func(k, v lua.LValue) {
-		count++
-	})
-	assert.Zero(t, count, "Expected no items in the table for non-matching input")
+	// Should be nil when no matches found
+	assert.Equal(t, lua.LNil, out, "Expected nil when no matches found")
 }
 
 // Happy Path: Function handles patterns with no capture groups by returning the full match in the Lua table.
@@ -67,7 +60,7 @@ func TestEvalRegex_NoCaptureGroups(t *testing.T) {
 	L.Push(lua.LString(input))
 
 	result := processor.EvalRegex(L)
-	assert.Equal(t, 0, result)
+	assert.Equal(t, 1, result, "Expected return value to be 1 (one value pushed to Lua stack)")
 
 	out := L.Get(-1)
 	tbl, ok := out.(*lua.LTable)
@@ -84,7 +77,7 @@ func TestEvalRegex_NoCaptureGroups(t *testing.T) {
 	assert.Equal(t, 1, count)
 }
 
-// Edge Case: Function panics or errors when given an invalid regex pattern.
+// Edge Case: Function handles invalid regex pattern by letting regexp.MustCompile panic (which is expected behavior)
 func TestEvalRegex_InvalidPattern(t *testing.T) {
 	L := lua.NewState()
 	defer L.Close()
@@ -92,15 +85,13 @@ func TestEvalRegex_InvalidPattern(t *testing.T) {
 	L.Push(lua.LString(pattern))
 	L.Push(lua.LString("someinput"))
 
-	defer func() {
-		if r := recover(); r == nil {
-			t.Error("Expected panic for invalid regex pattern, but did not panic")
-		}
-	}()
-	processor.EvalRegex(L)
+	// This should panic due to invalid regex pattern
+	assert.Panics(t, func() {
+		processor.EvalRegex(L)
+	}, "Expected panic for invalid regex pattern")
 }
 
-// Edge Case: Function returns an empty Lua table when input string is empty.
+// Edge Case: Function returns nil when input string is empty and pattern doesn't match.
 func TestEvalRegex_EmptyInputString(t *testing.T) {
 	L := lua.NewState()
 	defer L.Close()
@@ -108,19 +99,11 @@ func TestEvalRegex_EmptyInputString(t *testing.T) {
 	L.Push(lua.LString(""))
 
 	result := processor.EvalRegex(L)
-	assert.Equal(t, 0, result)
+	assert.Equal(t, 1, result, "Expected return value to be 1 (one value pushed to Lua stack)")
 
 	out := L.Get(-1)
-	tbl, ok := out.(*lua.LTable)
-	if !ok {
-		t.Fatalf("Expected Lua table, got %T", out)
-	}
-	// Should be empty
-	count := 0
-	tbl.ForEach(func(k, v lua.LValue) {
-		count++
-	})
-	assert.Zero(t, count, "Expected empty table when input is empty")
+	// Should be nil when no matches found
+	assert.Equal(t, lua.LNil, out, "Expected nil when input is empty and pattern doesn't match")
 }
 
 // Edge Case: Function handles nil or missing arguments gracefully without causing a runtime panic.
@@ -138,7 +121,7 @@ func TestEvalRegex_MissingArguments(t *testing.T) {
 }
 
 func TestEvalComplexRegex(t *testing.T) {
-	// 23:47:35.567068 processor.go:369          [g:22  ] [LUA]     Pistol_Round ^((Bulk_)?(Pistol|Rifle).*?Round.*?)$
+	// Test complex regex pattern with multiple capture groups
 	L := lua.NewState()
 	defer L.Close()
 	pattern := `^((Bulk_)?(Pistol|Rifle).*?Round.*?)$`
@@ -153,10 +136,13 @@ func TestEvalComplexRegex(t *testing.T) {
 	if !ok {
 		t.Fatalf("Expected Lua table, got %T", out)
 	}
-	count := 0
+
+	// Pattern should match: ["Pistol_Round", "Pistol_Round", "", "Pistol"]
+	// This creates 4 elements in the matches array, not 1
+	expectedCount := 4
+	actualCount := 0
 	tbl.ForEach(func(k, v lua.LValue) {
-		fmt.Println(k, v)
-		count++
+		actualCount++
 	})
-	assert.Equal(t, 1, count)
+	assert.Equal(t, expectedCount, actualCount, "Expected %d matches for pattern %q with input %q", expectedCount, pattern, input)
 }