From d35ce7b3901c009556b5729127e6c2595fc085e7 Mon Sep 17 00:00:00 2001
From: Bryan Garland <ferromag@outlook.com>
Date: Thu, 16 Jan 2025 14:38:18 -0500
Subject: [PATCH] fix #510 - Trigger syntax error if parenthesis do not match
 to inform user entry is invalid

---
 .../darkempire78/opencalculator/activities/MainActivity.kt  | 2 ++
 .../opencalculator/calculator/parser/Expression.kt          | 6 +++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/com/darkempire78/opencalculator/activities/MainActivity.kt b/app/src/main/java/com/darkempire78/opencalculator/activities/MainActivity.kt
index 85d66391..44c65abb 100644
--- a/app/src/main/java/com/darkempire78/opencalculator/activities/MainActivity.kt
+++ b/app/src/main/java/com/darkempire78/opencalculator/activities/MainActivity.kt
@@ -957,6 +957,8 @@ class MainActivity : AppCompatActivity() {
 
             val calculation = binding.input.text.toString()
 
+            Expression().addParenthesis(calculation)
+
             if (calculation != "") {
 
                 val resultString = calculationResult.toString()
diff --git a/app/src/main/java/com/darkempire78/opencalculator/calculator/parser/Expression.kt b/app/src/main/java/com/darkempire78/opencalculator/calculator/parser/Expression.kt
index 9694d236..04a41c57 100644
--- a/app/src/main/java/com/darkempire78/opencalculator/calculator/parser/Expression.kt
+++ b/app/src/main/java/com/darkempire78/opencalculator/calculator/parser/Expression.kt
@@ -102,7 +102,7 @@ class Expression {
 
     }
 
-    private fun addParenthesis(calculation: String): String {
+    fun addParenthesis(calculation: String): String {
         // Add ")" which lack
         var cleanCalculation = calculation
         var openParentheses = 0
@@ -121,6 +121,10 @@ class Expression {
                 cleanCalculation += ')'
             }
         }
+        // Trigger syntax error if missing '('
+        if (closeParentheses > openParentheses) {
+            syntax_error = true
+        }
 
         return cleanCalculation
     }