diff --git a/src/main.cpp b/src/main.cpp
index ef219f0..23b3767 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,8 +2,7 @@
 #include <cstdlib>
 #include <iostream>
 #include <fstream>
-#include <memory>
-#include <utility>
+#include <regex>
 
 using namespace argument_parser::conventions;
 
@@ -24,6 +23,13 @@ struct argument_parser::parsing_traits::parser_trait<Point> {
     }
 };
 
+template<>
+struct argument_parser::parsing_traits::parser_trait<std::regex> {
+    static std::regex parse(const std::string& input) {
+        return std::regex(input);
+    }
+};
+
 const std::initializer_list<argument_parser::conventions::convention const* const> conventions = {
     &gnu_argument_convention,
     &gnu_equal_argument_convention 
@@ -51,88 +57,54 @@ const auto cat = argument_parser::helpers::make_parametered_action<std::string>(
     file.close();
 });
 
-auto make_grep_action(argument_parser::base_parser& parser) {
-    std::shared_ptr<std::string> filename = std::make_shared<std::string>(""); 
-    std::shared_ptr<bool> grep_requested = std::make_shared<bool>(false);
-    std::shared_ptr<bool> grep_called = std::make_shared<bool>(false);
-    std::shared_ptr<std::string> pattern = std::make_shared<std::string>(); 
+auto grep(argument_parser::base_parser& parser, std::string const& filename, std::regex const& pattern) {
+    if (filename.empty()) {
+        std::cerr << "Missing filename" << std::endl; 
+        parser.display_help(conventions); 
+        exit(-1); 
+    }
+    std::ifstream file(filename);
+    if (!file.is_open()) {
+        std::cerr << "Could not open file: \"" << filename << '"' << std::endl; 
+        exit(-1);
+    }
 
-    auto grep_impl = [&parser] (std::string const& filename, std::string const& pattern) {
-        if (filename.empty()) {
-            std::cerr << "Missing filename" << std::endl; 
-            parser.display_help(conventions); 
-            exit(-1); 
+    for (std::string line; std::getline(file, line);) {
+        if (std::regex_search(line, pattern)) {
+            std::cout << line << std::endl;
         }
-        std::ifstream file(filename);
-        if (!file.is_open()) {
-            std::cerr << "Could not open file: \"" << filename << '"' << std::endl; 
-            exit(-1);
-        }
-        std::string line;
-        while (std::getline(file, line)) {
-            if (line.find(pattern) != std::string::npos) {
-                std::cout << line << std::endl;
-            }
-        }
-        file.close();
-    }; 
-
-    const auto filename_action = argument_parser::helpers::make_parametered_action<std::string>([filename, grep_called, grep_requested, &grep_impl, pattern](std::string const& file_name) {
-        std::ifstream file(file_name);
-        if (!file.is_open()) {
-            throw std::runtime_error("Could not open file");
-        }
-        *filename = file_name;
-        file.close();
-        if (*grep_requested && !(*grep_called)) {
-            grep_impl(file_name, *pattern);
-            *grep_called = true; 
-        }
-    });
-
-    const auto grep = argument_parser::helpers::make_parametered_action<std::string>([filename, &parser, &grep_impl, grep_requested, grep_called, pattern](std::string const& p) {
-        *grep_requested = true;
-        if (!filename || filename -> empty()) {
-            *grep_called = false; 
-            *pattern = p; 
-            return; 
-        }
-        grep_impl(*filename,  p);
-        *grep_called = true; 
-    });
-
-    return std::pair { filename_action, grep };
+    }
+    
+    file.close();
 }
 
 int main() {
     auto parser = argument_parser::parser{};
-    auto [file, grep] = make_grep_action(parser); 
 
     parser.add_argument("e", "echo", "echoes given variable", echo, false);
     parser.add_argument("ep", "echo-point", "echoes given point", echo_point, false);
-    parser.add_argument("f", "file", "File to grep, required only if using grep", file, false);
-    parser.add_argument("g", "grep", "Grep pattern, required only if using grep", grep, false);
+    parser.add_argument<std::string>("f", "file", "File to grep, required only if using grep",  false);
+    parser.add_argument<std::regex>("g", "grep", "Grep pattern, required only if using grep", false);
     parser.add_argument("c", "cat", "Prints the content of the file", cat, false);
     parser.add_argument("h", "help", "Displays this help text.", argument_parser::helpers::make_non_parametered_action([&parser]{
         parser.display_help(conventions); 
     }), false);
 
-    parser.add_argument<std::string>("t", "test_store", "Test store", false); 
     parser.add_argument<Point>("p", "point", "Test point", false);
     parser.handle_arguments(conventions);
-
-    auto store = parser.get_optional<std::string>("test_store"); 
-    if (store.has_value()) {
-        std::cout << "Stored value: " << store.value() << std::endl;
-    } else {
-        std::cout << "No stored value." << std::endl;
-    }
-
-    auto point = parser.get_optional<Point>("point");
-    if (point.has_value()) {
-        std::cout << "Stored point: " << point.value().x << ", " << point.value().y << std::endl;
-    } else {
-        std::cout << "No stored point." << std::endl;
+    
+    auto filename = parser.get_optional<std::string>("file");
+    auto pattern = parser.get_optional<std::regex>("grep");
+    if (filename && pattern) {
+        grep(parser, filename.value(), pattern.value());
+    } else if (filename) {
+        std::cerr << "Missing grep pattern" << std::endl; 
+        parser.display_help(conventions); 
+        exit(-1); 
+    } else if (pattern) {
+        std::cerr << "Missing filename" << std::endl; 
+        parser.display_help(conventions); 
+        exit(-1); 
     }
     
     return 0;