diff --git a/CMakeLists.txt b/CMakeLists.txt
index c46ed21c9..8e1e02045 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -182,7 +182,7 @@ enable_testing()
 find_program(${PROJECT_NAME}_MEMORY_CHECK_COMMAND valgrind)
 
 set(${PROJECT_NAME}_MEMORY_CHECK_OPTIONS
-  --error-exitcode=1 # = EXIT_FAILURE)
+  --error-exitcode=1 # = EXIT_FAILURE
   --leak-check=full
   --quiet
   --show-leak-kinds=all)
diff --git a/README.md b/README.md
index 670026675..dc89c7f1c 100644
--- a/README.md
+++ b/README.md
@@ -90,7 +90,7 @@ Procedures for each standard are provided by the following R7RS-style libraries:
 cmake -B build -DCMAKE_BUILD_TYPE=Release
 cd build
 make package
-sudo apt install build/meevax_0.5.228_amd64.deb
+sudo apt install build/meevax_0.5.229_amd64.deb
 ```
 
 or
@@ -122,9 +122,9 @@ sudo rm -rf /usr/local/share/meevax
 
 | Target Name | Description
 |-------------|-------------
-| `all`       | Build shared-library `libmeevax.0.5.228.so` and executable `meevax`
+| `all`       | Build shared-library `libmeevax.0.5.229.so` and executable `meevax`
 | `test`      | Test executable `meevax`
-| `package`   | Generate debian package `meevax_0.5.228_amd64.deb`
+| `package`   | Generate debian package `meevax_0.5.229_amd64.deb`
 | `install`   | Copy files into `/usr/local` directly
 
 ## Usage
diff --git a/VERSION b/VERSION
index 6e3ecf4f9..06fbeca31 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.5.228
+0.5.229
diff --git a/include/meevax/kernel/exact_integer.hpp b/include/meevax/kernel/exact_integer.hpp
index 3d2dff835..d56431ffa 100644
--- a/include/meevax/kernel/exact_integer.hpp
+++ b/include/meevax/kernel/exact_integer.hpp
@@ -39,23 +39,22 @@ inline namespace kernel
 
     explicit exact_integer(mpz_t const) noexcept;
 
-    explicit exact_integer(std::int8_t);
-
-    explicit exact_integer(std::int16_t);
-
-    explicit exact_integer(std::int32_t);
-
-    explicit exact_integer(std::int64_t);
-
-    explicit exact_integer(std::uint8_t);
-
-    explicit exact_integer(std::uint16_t);
-
-    explicit exact_integer(std::uint32_t);
-
-    explicit exact_integer(std::uint64_t);
-
-    explicit exact_integer(double);
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    explicit exact_integer(T x)
+    {
+      if constexpr (std::is_floating_point_v<T>)
+      {
+        mpz_init_set_d(value, x);
+      }
+      else if constexpr (std::is_signed_v<T>)
+      {
+        mpz_init_set_si(value, x);
+      }
+      else
+      {
+        mpz_init_set_ui(value, x);
+      }
+    }
 
     explicit exact_integer(std::string const&, int = 0);
 
@@ -67,49 +66,50 @@ inline namespace kernel
 
     explicit operator bool() const;
 
-    operator std::int8_t() const;
-
-    operator std::int16_t() const;
-
-    operator std::int32_t() const;
-
-    operator std::int64_t() const;
-
-    operator std::uint8_t() const;
-
-    operator std::uint16_t() const;
-
-    operator std::uint32_t() const;
-
-    operator std::uint64_t() const;
-
-    explicit operator float() const;
-
-    explicit operator double() const;
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    operator T() const
+    {
+      if constexpr (std::is_floating_point_v<T>)
+      {
+        return mpz_get_d(value);
+      }
+      else if constexpr (std::is_signed_v<T>)
+      {
+        return mpz_get_si(value);
+      }
+      else
+      {
+        return mpz_get_ui(value);
+      }
+    }
 
     auto square_root() const -> std::tuple<exact_integer, exact_integer>;
   };
 
-  auto operator ==(exact_integer const&, int const) -> bool;
-  auto operator !=(exact_integer const&, int const) -> bool;
-  auto operator < (exact_integer const&, int const) -> bool;
-  auto operator <=(exact_integer const&, int const) -> bool;
-  auto operator > (exact_integer const&, int const) -> bool;
-  auto operator >=(exact_integer const&, int const) -> bool;
-
-  auto operator ==(exact_integer const&, signed long const) -> bool;
-  auto operator !=(exact_integer const&, signed long const) -> bool;
-  auto operator < (exact_integer const&, signed long const) -> bool;
-  auto operator <=(exact_integer const&, signed long const) -> bool;
-  auto operator > (exact_integer const&, signed long const) -> bool;
-  auto operator >=(exact_integer const&, signed long const) -> bool;
-
-  auto operator ==(exact_integer const&, unsigned long const) -> bool;
-  auto operator !=(exact_integer const&, unsigned long const) -> bool;
-  auto operator < (exact_integer const&, unsigned long const) -> bool;
-  auto operator <=(exact_integer const&, unsigned long const) -> bool;
-  auto operator > (exact_integer const&, unsigned long const) -> bool;
-  auto operator >=(exact_integer const&, unsigned long const) -> bool;
+  #define DEFINE_COMPARISON_OPERATOR(SYMBOL)                                   \
+  template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>  \
+  auto operator SYMBOL(exact_integer const& a, T b)                            \
+  {                                                                            \
+    if constexpr (std::is_floating_point_v<T>)                                 \
+    {                                                                          \
+      return mpz_cmp_d(a.value, b) SYMBOL 0;                                   \
+    }                                                                          \
+    else if constexpr (std::is_signed_v<T>)                                    \
+    {                                                                          \
+      return mpz_cmp_si(a.value, b) SYMBOL 0;                                  \
+    }                                                                          \
+    else                                                                       \
+    {                                                                          \
+      return mpz_cmp_ui(a.value, b) SYMBOL 0;                                  \
+    }                                                                          \
+  } static_assert(true)
+
+  DEFINE_COMPARISON_OPERATOR(==);
+  DEFINE_COMPARISON_OPERATOR(!=);
+  DEFINE_COMPARISON_OPERATOR(< );
+  DEFINE_COMPARISON_OPERATOR(<=);
+  DEFINE_COMPARISON_OPERATOR(> );
+  DEFINE_COMPARISON_OPERATOR(>=);
 
   auto operator <<(std::ostream &, exact_integer const&) -> std::ostream &;
 
diff --git a/src/kernel/exact_integer.cpp b/src/kernel/exact_integer.cpp
index 3c498d050..527f8084e 100644
--- a/src/kernel/exact_integer.cpp
+++ b/src/kernel/exact_integer.cpp
@@ -53,51 +53,6 @@ inline namespace kernel
     mpz_init_set(value, z);
   }
 
-  exact_integer::exact_integer(std::int8_t si)
-  {
-    mpz_init_set_si(value, si);
-  }
-
-  exact_integer::exact_integer(std::int16_t si)
-  {
-    mpz_init_set_si(value, si);
-  }
-
-  exact_integer::exact_integer(std::int32_t si)
-  {
-    mpz_init_set_si(value, si);
-  }
-
-  exact_integer::exact_integer(std::int64_t si)
-  {
-    mpz_init_set_si(value, si);
-  }
-
-  exact_integer::exact_integer(std::uint8_t ui)
-  {
-    mpz_init_set_ui(value, ui);
-  }
-
-  exact_integer::exact_integer(std::uint16_t ui)
-  {
-    mpz_init_set_ui(value, ui);
-  }
-
-  exact_integer::exact_integer(std::uint32_t ui)
-  {
-    mpz_init_set_ui(value, ui);
-  }
-
-  exact_integer::exact_integer(std::uint64_t ui)
-  {
-    mpz_init_set_ui(value, ui);
-  }
-
-  exact_integer::exact_integer(double d)
-  {
-    mpz_init_set_d(value, d);
-  }
-
   exact_integer::exact_integer(std::string const& s, int radix)
   {
     if (mpz_init_set_str(value, (s.at(0) == '+' ? s.substr(1) : s).c_str(), radix))
@@ -136,56 +91,6 @@ inline namespace kernel
     return (*value)._mp_size;
   }
 
-  exact_integer::operator std::int8_t() const
-  {
-    return mpz_get_si(value);
-  }
-
-  exact_integer::operator std::int16_t() const
-  {
-    return mpz_get_si(value);
-  }
-
-  exact_integer::operator std::int32_t() const
-  {
-    return mpz_get_si(value);
-  }
-
-  exact_integer::operator std::int64_t() const
-  {
-    return mpz_get_si(value);
-  }
-
-  exact_integer::operator std::uint8_t() const
-  {
-    return mpz_get_ui(value);
-  }
-
-  exact_integer::operator std::uint16_t() const
-  {
-    return mpz_get_ui(value);
-  }
-
-  exact_integer::operator std::uint32_t() const
-  {
-    return mpz_get_ui(value);
-  }
-
-  exact_integer::operator std::uint64_t() const
-  {
-    return mpz_get_ui(value);
-  }
-
-  exact_integer::operator float() const
-  {
-    return mpz_get_d(value);
-  }
-
-  exact_integer::operator double() const
-  {
-    return mpz_get_d(value);
-  }
-
   auto exact_integer::square_root() const -> std::tuple<exact_integer, exact_integer>
   {
     exact_integer s, r;
@@ -193,27 +98,6 @@ inline namespace kernel
     return std::make_tuple(s, r);
   }
 
-  auto operator ==(exact_integer const& a, int const b) -> bool { return a == static_cast<signed long>(b); }
-  auto operator !=(exact_integer const& a, int const b) -> bool { return a != static_cast<signed long>(b); }
-  auto operator < (exact_integer const& a, int const b) -> bool { return a <  static_cast<signed long>(b); }
-  auto operator <=(exact_integer const& a, int const b) -> bool { return a <= static_cast<signed long>(b); }
-  auto operator > (exact_integer const& a, int const b) -> bool { return a >  static_cast<signed long>(b); }
-  auto operator >=(exact_integer const& a, int const b) -> bool { return a >= static_cast<signed long>(b); }
-
-  auto operator ==(exact_integer const& a, signed long const b) -> bool { return mpz_cmp_si(a.value, b) == 0; }
-  auto operator !=(exact_integer const& a, signed long const b) -> bool { return mpz_cmp_si(a.value, b) != 0; }
-  auto operator < (exact_integer const& a, signed long const b) -> bool { return mpz_cmp_si(a.value, b) <  0; }
-  auto operator <=(exact_integer const& a, signed long const b) -> bool { return mpz_cmp_si(a.value, b) <= 0; }
-  auto operator > (exact_integer const& a, signed long const b) -> bool { return mpz_cmp_si(a.value, b) >  0; }
-  auto operator >=(exact_integer const& a, signed long const b) -> bool { return mpz_cmp_si(a.value, b) >= 0; }
-
-  auto operator ==(exact_integer const& a, unsigned long const b) -> bool { return mpz_cmp_ui(a.value, b) == 0; }
-  auto operator !=(exact_integer const& a, unsigned long const b) -> bool { return mpz_cmp_ui(a.value, b) != 0; }
-  auto operator < (exact_integer const& a, unsigned long const b) -> bool { return mpz_cmp_ui(a.value, b) <  0; }
-  auto operator <=(exact_integer const& a, unsigned long const b) -> bool { return mpz_cmp_ui(a.value, b) <= 0; }
-  auto operator > (exact_integer const& a, unsigned long const b) -> bool { return mpz_cmp_ui(a.value, b) >  0; }
-  auto operator >=(exact_integer const& a, unsigned long const b) -> bool { return mpz_cmp_ui(a.value, b) >= 0; }
-
   auto operator <<(std::ostream & os, exact_integer const& datum) -> std::ostream &
   {
     return os << cyan(std::unique_ptr<char, gmp_free>(mpz_get_str(nullptr, 10, datum.value)).get());