feat(furvm): introduce comparison operators

furvm/include/furvm/instruction.hpp

@@ -65,6 +65,36 @@ enum class instruction_t : byte {
      */
     Mod,
 
+    /**
+     * @brief Compares two top-most things from the stack for equality.
+     */
+    Equals,
+
+    /**
+     * @brief Compares two top-most things from the stack for inequality.
+     */
+    NotEquals,
+
+    /**
+     * @brief Compares if the first top-most thing is less than the second top-most thing.
+     */
+    LessThan,
+
+    /**
+     * @brief Compares if the first top-most thing is greater than the second top-most thing.
+     */
+    GreaterThan,
+
+    /**
+     * @brief Compares if the first top-most thing is less than or equal to the second top-most thing.
+     */
+    LessEqual,
+
+    /**
+     * @brief Compares if the first top-most thing is greater than or equal to the second top-most thing.
+     */
+    GreaterEqual,
+
     /**
      * @brief Pushes a variable onto the stack.
      *

furvm/include/furvm/thing.hpp

@@ -135,6 +135,59 @@ public:
      * @return Shared pointer to result thing.
      */
     friend thing_p operator%(const thing_p& lhs, const thing_p& rhs);
+
+    /**
+     * @brief Compares two things for equality.
+     *
+     * @param lhs Left-hand-side thing.
+     * @param rhs Right-hand-side thing.
+     * @return Shared pointer to result thing.
+     */
+    friend thing_p operator==(const thing_p& lhs, const thing_p& rhs);
+
+    /**
+     * @brief Compares two things for equality.
+     *
+     * @param lhs Left-hand-side thing.
+     * @param rhs Right-hand-side thing.
+     * @return Shared pointer to result thing.
+     */
+    friend thing_p operator!=(const thing_p& lhs, const thing_p& rhs);
+    /**
+     * @brief Compares if the left thing is less than the right thing.
+     *
+     * @param lhs Left-hand-side thing.
+     * @param rhs Right-hand-side thing.
+     * @return Shared pointer to result thing.
+     */
+    friend thing_p operator<(const thing_p& lhs, const thing_p& rhs);
+
+    /**
+     * @brief Compares if the left thing is greater than the right thing.
+     *
+     * @param lhs Left-hand-side thing.
+     * @param rhs Right-hand-side thing.
+     * @return Shared pointer to result thing.
+     */
+    friend thing_p operator>(const thing_p& lhs, const thing_p& rhs);
+
+    /**
+     * @brief Compares if the left thing is less than or equal to the right thing.
+     *
+     * @param lhs Left-hand-side thing.
+     * @param rhs Right-hand-side thing.
+     * @return Shared pointer to result thing.
+     */
+    friend thing_p operator<=(const thing_p& lhs, const thing_p& rhs);
+
+    /**
+     * @brief Compares if the left thing is greater than or equal to the right thing.
+     *
+     * @param lhs Left-hand-side thing.
+     * @param rhs Right-hand-side thing.
+     * @return Shared pointer to result thing.
+     */
+    friend thing_p operator>=(const thing_p& lhs, const thing_p& rhs);
 public:
     /**
      * @brief Returns a new thing.
@@ -208,4 +261,4 @@ private:
 
 } // namespace furvm
 
-#endif // FURVM_THING_HPP
+#endif // FURVM_THING_HPP