feat(furvm): introduce module, instruction and constant

furvm/include/furvm/context.hpp

@@ -1,14 +1,18 @@
 #ifndef FURVM_CONTEXT_HPP
 #define FURVM_CONTEXT_HPP
 
+#include "furvm/fwd.hpp"
+#include "furvm/module.hpp"
+
+#include <memory>
+#include <type_traits>
+#include <vector>
+
 namespace furvm {
 
-/**
- * @brief Context.
- *
- * A furvm context.
- */
 class context {
+public:
+    using value_type = std::unique_ptr<mod>;
 public:
     context()  = default;
     ~context() = default;
@@ -25,7 +29,71 @@ public:
 
     context(const context&)            = delete;
     context& operator=(const context&) = delete;
+public:
+    /**
+     * @brief Adds a module to this context.
+     *
+     * @param args Arguments to forward to module's constructor.
+     * @return An index to the emplaced module.
+     */
+    template <typename... Args, typename = std::enable_if_t<std::is_constructible_v<mod, Args...>>>
+    constexpr module_index emplace(Args&&... args) {
+        module_index index = m_modules.size();
+        m_modules.emplace_back(std::make_unique<mod>(std::forward<Args>(args)...));
+        return index;
+    }
+
+    /**
+     * @brief Erases a module from this context.
+     *
+     * @param index Index to the module.
+     * @return Old value.
+     */
+    value_type erase(module_index index) {
+        if (index >= m_modules.size()) return nullptr;
+        return std::move(m_modules[index]);
+    }
+
+    /**
+     * @brief Returns a module of this context.
+     *
+     * @param index Position of the module.
+     * @return The module.
+     */
+    constexpr value_type& operator[](module_index index) { return m_modules[index]; }
+
+    /**
+     * @brief Returns a module of this context.
+     *
+     * @param index Position of the module.
+     * @return The module.
+     */
+    constexpr const value_type& operator[](module_index index) const { return m_modules[index]; }
+
+    /**
+     * @brief Returns a module of this context.
+     *
+     * @param index Position of the module.
+     * @return The module.
+     */
+    constexpr value_type& at(module_index index) { return m_modules.at(index); }
+
+    /**
+     * @brief Returns a module of this context.
+     *
+     * @param index Position of the module.
+     * @return The module.
+     */
+    constexpr const value_type& at(module_index index) const { return m_modules.at(index); }
+
+    /**
+     * @brief Returns how many does this context have modules.
+     *
+     * @return The module count.
+     */
+    constexpr size_t size() const { return m_modules.size(); }
 private:
+    std::vector<std::unique_ptr<mod>> m_modules;
 };
 
 } // namespace furvm