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+/**
+ * Alee Forth: A portable and concise Forth implementation in modern C++.
+ * Copyright (C) 2023  Clyne Sullivan <clyne@bitgloo.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef ALEEFORTH_DICTIONARY_HPP
+#define ALEEFORTH_DICTIONARY_HPP
+
+#include "types.hpp"
+
+#include <cstddef>
+#include <string_view>
+
+struct Dictionary
+{
+    Addr here = 1;
+    Addr latest = 0;
+
+    virtual Cell read(Addr) const = 0;
+    virtual int write(Addr, Cell) = 0;
+
+    Addr allot(Cell amount) {
+	Addr old = here;
+	here += amount;
+	return old;
+    }
+
+    void add(Cell value) {
+    	write(here++, value);
+    }
+
+    void addDefinition(std::string_view str) {
+        add(str.size());
+	for (char c : str)
+	    add(c);
+
+	if (here & 1)
+	    allot(1);
+    }
+
+    bool issame(Addr addr, std::string_view str, std::size_t n) {
+	if (str.size() != n)
+	    return false;
+
+        for (char c : str) {
+	    if (read(addr++) != c)
+		return false;
+	}
+	    
+	return true;
+    }
+
+    Addr find(std::string_view str) {
+        if (latest == 0)
+	    return 0;
+
+	auto lt = latest;
+	do {
+            const auto l = read(lt);
+	    const auto len = l & 0x1F;
+
+	    if (issame(lt + 1, str, len)) {
+	        return lt;
+	    } else {
+		lt -= l >> 6;
+	    }
+	} while (lt);
+
+	return 0;
+    }
+
+    Addr getexec(Addr addr) {
+	const auto len = read(addr) & 0x1F;
+	return ((addr + 1 + len) + 1) & ~1;
+    }
+};
+
+#endif // ALEEFORTH_DICTIONARY_HPP
+