1 files changed, 64 insertions, 0 deletions
diff --git a/example/turing/src/state.h b/example/turing/src/state.h
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+++ b/example/turing/src/state.h
@@ -0,0 +1,64 @@
+#ifndef TYPEASVALUE_EXAMPLE_TURING_SRC_STATE_H_
+#define TYPEASVALUE_EXAMPLE_TURING_SRC_STATE_H_
+
+#include "type.h"
+#include "list/list.h"
+#include "list/operation/higher/find.h"
+
+namespace machine {
+
+namespace state {
+
+struct field {
+	using ID    = tav::Size<0>;
+	using READ  = tav::Size<1>;
+	using WRITE = tav::Size<2>;
+	using NEXT  = tav::Size<3>;
+	using MOVE  = tav::Size<4>;
+};
+
+// (define (state_predicate id read)
+//   (lambda (state)
+//           (and (= id   (nth ID   state))
+//                (= read (nth READ state)))))
+template <
+	typename Id,
+	typename Read
+>
+struct state_predicate {
+	template <typename State>
+	using function = tav::And<
+		tav::IsEqualValue<Id,   tav::Nth<field::ID,   State>>,
+		tav::IsEqualValue<Read, tav::Nth<field::READ, State>>
+	>;
+};
+
+// (define (findState id read states)
+//   (find (state_predicate id read) states))
+template <
+	typename Id,
+	typename Read,
+	typename States
+>
+using findState = tav::Find<
+	state_predicate<Id, Read>::template function,
+	States
+>;
+
+// (define (transition states)
+//   (lambda (state symbol)
+//           (findState state symbol states)))
+template <typename States>
+struct transition {
+	template <
+		typename State,
+		typename Symbol
+	>
+	using state = findState<State, Symbol, States>;
+};
+
+}
+
+}
+
+#endif // TYPEASVALUE_EXAMPLE_TURING_SRC_STATE_H_