fix unchecked selection of brackets that caught and removed unrelated tokens

src/syntaxer.cpp

@@ -29,6 +29,70 @@ static int rank_op(const Expression::Token::Operator o)
 	}
 }
 
+static int same_lvl_opa_location(const std::vector<Expression::Token>& tv, const int location)
+{
+	for (int i = location - 1, lv = 0; i >= 0; i--)
+	{
+		const Expression::Token &t = tv[i];
+
+		if (t.t != Expression::Token::OPERATOR)
+		{
+			continue;
+		}
+
+		if (t.v.o == Expression::Token::CPA)
+		{
+			lv++;
+		}
+
+		if (t.v.o == Expression::Token::OPA)
+		{
+			if (!lv)
+			{
+				return i;
+			}
+			else
+			{
+				lv--;
+			}
+		}
+	}
+
+	return -1;
+}
+
+static int same_lvl_cpa_location(const std::vector<Expression::Token>& tv, const int location)
+{
+	for (int i = location + 1, lv = 0, l = tv.size(); i < l; i++)
+	{
+		const Expression::Token &t = tv[i];
+
+		if (t.t != Expression::Token::OPERATOR)
+		{
+			continue;
+		}
+
+		if (t.v.o == Expression::Token::OPA)
+		{
+			lv++;
+		}
+
+		if (t.v.o == Expression::Token::CPA)
+		{
+			if (!lv)
+			{
+				return i;
+			}
+			else
+			{
+				lv--;
+			}
+		}
+	}
+
+	return tv.size() - 1;
+}
+
 static void highlight_issue(const std::vector<Expression::Token>& tv, const int location)
 {
 	int start = location - 7 < 0 ? 0 : location - 7;
@@ -634,9 +698,14 @@ static Expression::Token::Operator get_prior_mop(const std::vector<Expression::T
 
 static void open_brackets(std::vector<Expression::Token>& tv, const Range &r)
 {
+	Range brackets(
+		same_lvl_opa_location(tv, get_mop_location(tv, r.start)),
+		same_lvl_cpa_location(tv, get_mop_location(tv, r.finish))
+	);
+
 	std::vector<int> hl;
-	hl.emplace_back(get_mop_location(tv, r.start) - 2);
-	hl.emplace_back(get_mop_location(tv, r.finish) + 2);
+	hl.emplace_back(brackets.start);
+	hl.emplace_back(brackets.finish);
 	Parser::print_math_vector(tv, hl);
 
 	if (Expression::Token::Operator po = get_prior_mop(tv, get_mop_location(tv, r.start)); po == Expression::Token::SUB || po == Expression::Token::DIV)
@@ -665,8 +734,8 @@ static void open_brackets(std::vector<Expression::Token>& tv, const Range &r)
 		}
 	}
 
-	tv.erase(tv.begin() + get_mop_location(tv, r.start) - 2);
-	tv.erase(tv.begin() + get_mop_location(tv, r.finish) + 2);
+	tv.erase(tv.begin() + brackets.finish);
+	tv.erase(tv.begin() + brackets.start);
 }
 
 static void remove_extra_brackets(std::vector<Expression::Token>& tv)