derivation_clause: extract derivation clause type

2 files changed, 115 insertions, 101 deletions

diff --git a/include/newtype/derivation_clause.hpp b/include/newtype/derivation_clause.hpp
new file mode 100644
index 0000000..6550b4c
--- /dev/null
+++ b/include/newtype/derivation_clause.hpp
@@ -0,0 +1,114 @@
+#ifndef NEWTYPE_DERIVATION_CLAUSE_HPP
+#define NEWTYPE_DERIVATION_CLAUSE_HPP
+
+#include "newtype/derivable.hpp"
+
+#include <type_traits>
+
+namespace nt
+{
+
+  /**
+   * A @p deriving clause type
+   *
+   * @tparam DerivableTags A list of tag types defining a set of derivable features
+   */
+  template<typename... DerivableTags>
+  struct derivation_clause
+  {
+    constexpr derivation_clause(derivable<DerivableTags>...) noexcept
+    {
+    }
+
+    /**
+     * Check whether the derivation clause contains a given derivable
+     */
+    template<typename DerivableTag>
+    auto constexpr operator()(derivable<DerivableTag>) const noexcept -> bool
+    {
+      return (std::is_same_v<DerivableTags, DerivableTag> || ...);
+    }
+
+    /**
+     * Check whether the derivation clause contains all derivables in a given lists
+     */
+    template<typename DerivableTag, typename... RemainingDerivableTags>
+    auto constexpr operator()(derivable<DerivableTag>, derivable<RemainingDerivableTags>...) const noexcept -> bool
+    {
+      return (*this)(derivable<DerivableTag>{}) && (*this)(derivable<RemainingDerivableTags>{}...);
+    }
+
+    /**
+     * Check whether this derivation clause is less than an other derivation clause
+     *
+     * A derivation clause is considered less than an other derivation clause iff. its set of derivables is a strict subset of
+     * the set derivables of the other.
+     */
+    template<typename... OtherDerivableTags>
+    auto constexpr operator<(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
+    {
+      return (sizeof...(DerivableTags) < sizeof...(OtherDerivableTags)) && other(derivable<DerivableTags>{}...);
+    }
+
+    /**
+     * Check whether this derivation clause is greater than an other derivation clause
+     *
+     * A derivation clause is considered greater than an other derivation clause iff. its set of derivables is a strict superset
+     * of the set derivables of the other.
+     */
+    template<typename... OtherDerivableTags>
+    auto constexpr operator>(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
+    {
+      return other < *this;
+    }
+
+    /**
+     * Check whether this derivation clause is equal to an other derivation clause
+     *
+     * Two derivation clauses are considered equal if both have the same set of derivables
+     */
+    template<typename... OtherDerivableTags>
+    auto constexpr operator==(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
+    {
+      return sizeof...(DerivableTags) == sizeof...(OtherDerivableTags) && other(derivable<DerivableTags>{}...);
+    }
+
+    /**
+     * Check whether this derivation clause is not equal to an other derivation clause
+     *
+     * Two derivation clauses are considered not equal if neither has the same set of derivables as the other
+     */
+    template<typename... OtherDerivableTags>
+    auto constexpr operator!=(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
+    {
+      return !(*this == other);
+    }
+
+    /**
+     * Check whether this derivation clause is less-than or equal to an other derivation clause
+     *
+     * @see nt::distinct::operator==
+     * @see nt::distinct::operator<
+     */
+    template<typename... OtherDerivableTags>
+    auto constexpr operator<=(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
+    {
+      return *this < other || *this == other;
+    }
+
+    /**
+     * Check whether this derivation clause is greater-than or equal to an other derivation clause
+     *
+     * @see nt::distinct::operator==
+     * @see nt::distinct::operator<
+     */
+    template<typename... OtherDerivableTags>
+    auto constexpr operator>=(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
+    {
+      return *this > other || *this == other;
+    }
+  };
+
+}  // namespace nt
+
+#endif
\ No newline at end of file
diff --git a/include/newtype/deriving.hpp b/include/newtype/deriving.hpp
index 431742f..7224d55 100644
--- a/include/newtype/deriving.hpp
+++ b/include/newtype/deriving.hpp
@@ -2,6 +2,7 @@
 #define NEWTYPE_DERIVING_HPP
 
 #include "newtype/derivable.hpp"
+#include "newtype/derivation_clause.hpp"
 
 #include <type_traits>
 
@@ -9,107 +10,6 @@ namespace nt
 {
 
   /**
-   * A @p deriving clause type
-   *
-   * @tparam DerivableTags A list of tag types defining a set of derivable features
-   */
-  template<typename... DerivableTags>
-  struct derivation_clause
-  {
-    constexpr derivation_clause(derivable<DerivableTags>...) noexcept
-    {
-    }
-
-    /**
-     * Check whether the derivation clause contains a given derivable
-     */
-    template<typename DerivableTag>
-    auto constexpr operator()(derivable<DerivableTag>) const noexcept -> bool
-    {
-      return (std::is_same_v<DerivableTags, DerivableTag> || ...);
-    }
-
-    /**
-     * Check whether the derivation clause contains all derivables in a given lists
-     */
-    template<typename DerivableTag, typename... RemainingDerivableTags>
-    auto constexpr operator()(derivable<DerivableTag>, derivable<RemainingDerivableTags>...) const noexcept -> bool
-    {
-      return (*this)(derivable<DerivableTag>{}) && (*this)(derivable<RemainingDerivableTags>{}...);
-    }
-
-    /**
-     * Check whether this derivation clause is less than an other derivation clause
-     *
-     * A derivation clause is considered less than an other derivation clause iff. its set of derivables is a strict subset of
-     * the set derivables of the other.
-     */
-    template<typename... OtherDerivableTags>
-    auto constexpr operator<(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
-    {
-      return (sizeof...(DerivableTags) < sizeof...(OtherDerivableTags)) && other(derivable<DerivableTags>{}...);
-    }
-
-    /**
-     * Check whether this derivation clause is greater than an other derivation clause
-     *
-     * A derivation clause is considered greater than an other derivation clause iff. its set of derivables is a strict superset
-     * of the set derivables of the other.
-     */
-    template<typename... OtherDerivableTags>
-    auto constexpr operator>(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
-    {
-      return other < *this;
-    }
-
-    /**
-     * Check whether this derivation clause is equal to an other derivation clause
-     *
-     * Two derivation clauses are considered equal if both have the same set of derivables
-     */
-    template<typename... OtherDerivableTags>
-    auto constexpr operator==(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
-    {
-      return sizeof...(DerivableTags) == sizeof...(OtherDerivableTags) && other(derivable<DerivableTags>{}...);
-    }
-
-    /**
-     * Check whether this derivation clause is not equal to an other derivation clause
-     *
-     * Two derivation clauses are considered not equal if neither has the same set of derivables as the other
-     */
-    template<typename... OtherDerivableTags>
-    auto constexpr operator!=(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
-    {
-      return !(*this == other);
-    }
-
-    /**
-     * Check whether this derivation clause is less-than or equal to an other derivation clause
-     *
-     * @see nt::distinct::operator==
-     * @see nt::distinct::operator<
-     */
-    template<typename... OtherDerivableTags>
-    auto constexpr operator<=(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
-    {
-      return *this < other || *this == other;
-    }
-
-    /**
-     * Check whether this derivation clause is greater-than or equal to an other derivation clause
-     *
-     * @see nt::distinct::operator==
-     * @see nt::distinct::operator<
-     */
-    template<typename... OtherDerivableTags>
-    auto constexpr operator>=(derivation_clause<OtherDerivableTags...> other) const noexcept -> bool
-    {
-      return *this > other || *this == other;
-    }
-  };
-
-  /**
    * Create a new derivation clause with the given derivables
    */
   template<typename... DerivableTags>