diff --git a/main.go b/main.go
index 9787ba8..7115dbc 100644
--- a/main.go
+++ b/main.go
@@ -106,7 +106,7 @@ func main() {
 	patternModified := false
 
 	if strings.Contains(regexPattern, "!num") {
-		regexPattern = strings.ReplaceAll(regexPattern, "!num", "(\\d*\\.?\\d+)")
+		regexPattern = strings.ReplaceAll(regexPattern, "!num", "(-?\\d*\\.?\\d+)")
 		patternModified = true
 	}
 
diff --git a/main_test.go b/main_test.go
index 4f410b0..62f145f 100644
--- a/main_test.go
+++ b/main_test.go
@@ -35,7 +35,7 @@ func TestSimpleValueMultiplication(t *testing.T) {
 	luaExpr := `*1.5`
 	luaScript := buildLuaScript(luaExpr)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -68,7 +68,7 @@ func TestShorthandNotation(t *testing.T) {
 	luaExpr := `v1 * 1.5` // Use direct assignment syntax
 	luaScript := buildLuaScript(luaExpr)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr	)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -100,7 +100,7 @@ func TestArrayNotation(t *testing.T) {
 	luaExpr := `v1 = v1 * 1.5` // Use direct assignment syntax
 	luaScript := buildLuaScript(luaExpr)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -140,7 +140,7 @@ func TestMultipleMatches(t *testing.T) {
 	luaExpr := `*1.5`
 	luaScript := buildLuaScript(luaExpr)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -182,7 +182,7 @@ func TestMultipleCaptureGroups(t *testing.T) {
 	}
 	t.Logf("Matches: %v", matches)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -225,7 +225,7 @@ func TestModifyingMultipleValues(t *testing.T) {
 	}
 	t.Logf("Matches: %v", matches)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -259,7 +259,7 @@ func TestDecimalValues(t *testing.T) {
 	luaExpr := `v1 = v1 * v2` // Use direct assignment syntax
 	luaScript := buildLuaScript(luaExpr)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr	)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -291,7 +291,7 @@ func TestLuaMathFunctions(t *testing.T) {
 	luaExpr := `v1 = math.sqrt(v1)` // Use direct assignment syntax
 	luaScript := buildLuaScript(luaExpr)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -325,7 +325,7 @@ func TestDirectAssignment(t *testing.T) {
 
 	t.Logf("Lua script: %s", luaScript) // Log the generated script for debugging
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -415,7 +415,7 @@ func TestProcessingSampleFiles(t *testing.T) {
 			t.Logf("Lua expression: %s", tc.luaExpr)
 
 			// Process the content
-			modifiedContent, err := process(tc.fileContent, regex, luaScript)
+			modifiedContent, _, _, err := process(tc.fileContent, regex, luaScript, "test.xml", tc.luaExpr)
 			if err != nil {
 				t.Fatalf("Error processing file: %v", err)
 			}
@@ -465,7 +465,7 @@ func TestFileOperations(t *testing.T) {
 		t.Logf("Lua expression: %s", luaExpr)
 
 		// Process the content
-		modifiedContent, err := process(fileContent, regex, luaScript)
+		modifiedContent, _, _, err := process(fileContent, regex, luaScript, "test.xml", luaExpr	)
 		if err != nil {
 			t.Fatalf("Error processing file: %v", err)
 		}
@@ -502,7 +502,7 @@ func TestFileOperations(t *testing.T) {
 		t.Logf("Lua expression: %s", luaExpr)
 
 		// Process the content
-		modifiedContent, err := process(fileContent, regex, luaScript)
+		modifiedContent, _, _, err := process(fileContent, regex, luaScript, "test.xml", luaExpr)
 		if err != nil {
 			t.Fatalf("Error processing file: %v", err)
 		}
@@ -537,7 +537,7 @@ func TestFileOperations(t *testing.T) {
 		t.Logf("Lua expression: %s", luaExpr)
 
 		// Process the content
-		modifiedContent, err := process(fileContent, regex, luaScript)
+		modifiedContent, _, _, err := process(fileContent, regex, luaScript, "test.xml", luaExpr)
 		if err != nil {
 			t.Fatalf("Error processing file: %v", err)
 		}
@@ -574,7 +574,7 @@ func TestHigherVariableIndices(t *testing.T) {
 
 		// Expected: 10 + 20 * 30 / 40 - 50 = 10 + 15 - 50 = -25
 
-		modifiedContent, err := process(fileContents, regex, luaScript)
+		modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 		if err != nil {
 			t.Fatalf("Error processing with v3-v5: %v", err)
 		}
@@ -594,7 +594,7 @@ func TestHigherVariableIndices(t *testing.T) {
 
 		// Expected: 10 * 110 = 1100
 
-		modifiedContent, err := process(fileContents, regex, luaScript)
+		modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 		if err != nil {
 			t.Fatalf("Error processing with v11: %v", err)
 		}
@@ -613,7 +613,7 @@ func TestHigherVariableIndices(t *testing.T) {
 		luaScript := buildLuaScript(luaExpr)
 
 		// This should double the value
-		modifiedContent, err := process(fileContents, regex, luaScript)
+		modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 		if err != nil {
 			t.Fatalf("Error processing with v0: %v", err)
 		}
@@ -649,7 +649,7 @@ func TestMultiStatementExpression(t *testing.T) {
 
 	t.Logf("Generated Lua script: %s", luaScript)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}
@@ -698,7 +698,7 @@ end
 
 	t.Logf("Generated Lua script: %s", luaScript)
 
-	modifiedContent, err := process(fileContents, regex, luaScript)
+	modifiedContent, _, _, err := process(fileContents, regex, luaScript, "test.xml", luaExpr)
 	if err != nil {
 		t.Fatalf("Error processing file: %v", err)
 	}