simple c++ refs

1 files changed, 49 insertions, 0 deletions

diff --git a/starts/meaning-vm/helpers.hpp b/starts/meaning-vm/helpers.hpp
new file mode 100644
index 0000000..f21952a
--- /dev/null
+++ b/starts/meaning-vm/helpers.hpp
@@ -0,0 +1,49 @@
+#include "concept.hpp"
+
+// Makes string values interchangeable with the concepts
+//   they name.
+template<>
+struct value<std::string> : public concept, public std::string
+{
+	//using std::string::basic_string;
+	value(std::string);
+	value(cid);
+	operator cid();
+	static value& of(cid c)
+	{
+		return *static_cast<value*>(c);
+	}
+};
+
+using str = value<std::string>;
+
+cid operator"" _c(const char* str, std::size_t len)
+{
+	return value<std::string>({str,len});
+}
+
+#include <unordered_map>
+
+concept namesByConcept;
+std::unordered_map<value<std::string>,concept,std::hash<std::string>> conceptsByName;
+
+value<std::string>::value(std::string s)
+: std::string(s)
+{ }
+
+value<std::string>::value(cid c)
+: std::string(of(namesByConcept.get(c)))
+{ }
+
+value<std::string>::operator cid()
+{
+	try {
+		return &conceptsByName.at(*this);
+	} catch (std::out_of_range) {
+		auto insertion = conceptsByName.emplace(*this, concept());
+		cid con = &insertion.first->second;
+		cid nam = const_cast<cid>((const cid)&insertion.first->first);
+		namesByConcept.link(con, nam);
+		return con;
+	}
+}