Refactored libimhex to and includes to better represent it as library

plugins/libimhex/include/hex/lang/preprocessor.hpp

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <hex.hpp>
+
+#include "token.hpp"
+
+#include <functional>
+#include <set>
+#include <string>
+#include <unordered_map>
+#include <utility>
+
+namespace hex::lang {
+
+    class Preprocessor {
+    public:
+        Preprocessor();
+
+        std::optional<std::string> preprocess(const std::string& code, bool initialRun = true);
+
+        void addPragmaHandler(const std::string &pragmaType, const std::function<bool(const std::string&)> &function);
+        void addDefaultPragmaHandlers();
+
+        const std::pair<u32, std::string>& getError() { return this->m_error; }
+
+    private:
+        using PreprocessorError = std::pair<u32, std::string>;
+
+        [[noreturn]] void throwPreprocessorError(std::string_view error, u32 lineNumber) const {
+            throw PreprocessorError(lineNumber, "Preprocessor: " + std::string(error));
+        }
+
+        std::unordered_map<std::string, std::function<bool(std::string)>> m_pragmaHandlers;
+
+        std::set<std::pair<std::string, std::string>> m_defines;
+        std::set<std::pair<std::string, std::string>> m_pragmas;
+
+        std::pair<u32, std::string> m_error;
+    };
+
+}