From 8798ee646df00d07974e7979dbdbb4edab8441e1 Mon Sep 17 00:00:00 2001
From: tovjemam <tovjemam@deadfish.cz>
Date: Thu, 4 Dec 2025 11:30:41 +0100
Subject: [PATCH] Add terminal

---
 src/main.cpp        |   4 ++
 src/mp/lib.hpp      |   2 +-
 src/term/mpterm.hpp | 169 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 174 insertions(+), 1 deletion(-)
 create mode 100644 src/term/mpterm.hpp

diff --git a/src/main.cpp b/src/main.cpp
index 42d154a..b7b333e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,6 +2,7 @@
 #include <iostream>
 
 #include "mp/mp.hpp"
+#include "term/mpterm.hpp"
 
 template <class T>
 static void PrintInt(const char* name, const T& val)
@@ -181,4 +182,7 @@ int main()
         }
     }
 
+    MpTerm<mp::UNLIMITED> term;
+    term.run();
+
 }
\ No newline at end of file
diff --git a/src/mp/lib.hpp b/src/mp/lib.hpp
index cbb0c89..8596a20 100644
--- a/src/mp/lib.hpp
+++ b/src/mp/lib.hpp
@@ -101,7 +101,7 @@ inline T factorial(const T& n)
     }
 
     T result = 1;
-    for (T i = 2; i <= n; ++i)
+    for (T i = 2; i <= n; i += 1)
     {
         result *= i;
     }
diff --git a/src/term/mpterm.hpp b/src/term/mpterm.hpp
new file mode 100644
index 0000000..2d6ba56
--- /dev/null
+++ b/src/term/mpterm.hpp
@@ -0,0 +1,169 @@
+#pragma once
+
+#include <array>
+#include <cstddef>
+#include <iostream>
+#include <regex>
+#include <string>
+
+#include "mp/int.hpp"
+#include "mp/lib.hpp"
+#include "mp/math.hpp"
+
+template <size_t Size>
+class MpTerm
+{
+public:
+    using MyInt = mp::Int<Size>;
+
+    MpTerm() = default;
+
+    void run()
+    {
+        const std::regex bin_op_regex(R"(^\s*([\-\+]?\d+|\$\d)\s*([\+\-\/\*])\s*([\-\+]?\d+|\$\d)\s*$)");
+        const std::regex un_op_regex(R"(^\s*([\-\+]?\d+|\$\d)\s*([\!])\s*$)");
+
+        while (true)
+        {
+            std::cout << "> ";
+            std::string line;
+            if (!std::getline(std::cin, line))
+                break;
+
+            if (line == "exit" || line == "quit")
+                break;
+
+            if (line == "bank")
+            {
+                print_history();
+                continue;
+            }
+
+            std::smatch match;
+
+            if (std::regex_match(line, match, bin_op_regex))
+            {
+                binary_op(match[1], match[3], match[2].str()[0]);
+            }
+            else if (std::regex_match(line, match, un_op_regex))
+            {
+                if (match[2].str() == "!")
+                {
+                    factorial(match[1]);
+                }
+                else
+                {
+                    std::cout << "Unknown unary operator." << std::endl;
+                }
+            }
+            else
+            {
+                std::cout << "Invalid command format." << std::endl;
+            }
+        }
+    }
+
+private:
+    void binary_op(const std::string& lhs_str, const std::string& rhs_str, char op)
+    {
+        MyInt lhs = parse_operand(lhs_str);
+        MyInt rhs = parse_operand(rhs_str);
+
+        MyInt result;
+
+        try
+        {
+            switch (op)
+            {
+            case '+':
+                result = lhs + rhs;
+                break;
+            case '-':
+                result = lhs - rhs;
+                break;
+            case '*':
+                result = lhs * rhs;
+                break;
+            case '/':
+                result = lhs / rhs;
+                break;
+            default:
+                throw std::invalid_argument("Unknown operator");
+            }
+
+            output(result);
+        }
+        catch (const mp::OverflowErrorOf<MyInt, MyInt>& e)
+        {
+            std::cout << "Warning: Result overflew" << std::endl;
+            output(e.value());
+        }
+        catch (const std::exception& e)
+        {
+            std::cout << "Error: " << e.what() << std::endl;
+        }
+
+    }
+
+    void factorial(const std::string& operand_str)
+    {
+        MyInt operand = parse_operand(operand_str);
+
+        try
+        {
+            output(mp::factorial(operand));
+        }
+        catch (const std::exception& e)
+        {
+            std::cout << "Error: " << e.what() << std::endl;
+        }
+    }
+
+    void output(const MyInt& value)
+    {
+        m_history[m_next] = value;
+        m_next = (m_next + 1) % HISTORY;
+        print_var(1);
+    }
+
+    MyInt parse_operand(const std::string& token)
+    {
+        if (token.size() > 0 && token[0] == '$')
+        {
+            size_t idx = std::stoul(token.substr(1));
+            return m_history[get_memory_idx(idx)];
+        }
+        else
+        {
+            return mp::from_string<Size>(token.c_str());
+        }
+    }
+
+    void print_history() const
+    {
+        for (size_t i = 1; i <= HISTORY; ++i)
+        {
+            print_var(i);
+        }
+    }
+
+    void print_var(size_t num) const
+    {
+        std::cout << '$' << num << " = " << mp::to_string(m_history[get_memory_idx(num)]) << std::endl;
+    }
+
+    size_t get_memory_idx(size_t num) const
+    {
+        if (num == 0 || num > HISTORY)
+        {
+            throw std::out_of_range("Memory index out of range");
+        }
+        return (m_next + HISTORY - num) % HISTORY;
+    }
+
+private:
+    static constexpr size_t HISTORY = 5;
+
+    std::array<MyInt, HISTORY> m_history;
+    size_t m_next = 0;
+};
\ No newline at end of file