[WIP] Coding Style Guide

doc/src/dev/coding_style.rst

@@ -0,0 +1,217 @@
+
+Coding Style
+=============
+
+Naming Conventions
+~~~~~~~~~~~~~
+
+Consistent naming makes code easier to read, search, and maintain.
+The following rules help enforce a uniform naming style throughout the codebase:
+
+General Rules
+-------------
+
+- Use descriptive and unambiguous names.
+- Avoid abbreviations unless they are widely understood (e.g., `id`, `ctx`, `cfg`).
+- Prefer clarity over brevity.
+
+Specific Conventions
+--------------------
+
+- **Class names** use `PascalCase`.
+
+  .. code-block:: cpp
+
+      class DecompNetlistRouter {
+      };
+
+- **Variable and function names** use `snake_case`.
+
+  .. code-block:: cpp
+
+      int net_count;
+      void estimate_wirelength();
+
+- **Private member variables and private methods** should end with an underscore `_`.
+
+  .. code-block:: cpp
+
+      class Example {
+      private:
+          int count_;
+          void update_state_();
+      };
+
+- **Enums** should use `enum class` instead of traditional enums. Enum names should start with `e_`.
+
+  .. code-block:: cpp
+
+      enum class e_heap_type {
+          INVALID_HEAP = 0,
+          BINARY_HEAP,
+          FOUR_ARY_HEAP,
+      };
+
+- **Trivial structs** that primarily store data without behavior should be prefixed with `t_`.
+
+  .. code-block:: cpp
+
+      struct t_dijkstra_data {
+          vtr::vector<RRNodeId, bool> node_expanded;
+          vtr::vector<RRNodeId, float> node_visited_costs;
+          std::priority_queue<PQ_Entry> pq;
+      };
+
+- **Source and header file names** use `snake_case` and should be short but descriptive.
+
+  Example: `router_lookahead_map.cpp`, `netlist_walker.h`
+
+
+Use of `auto`
+~~~~~~~~~~~~~
+
+Use `auto` only when the type is long, complex, or hard to write explicitly.
+
+Examples where `auto` is appropriate:
+
+.. code-block:: cpp
+
+    auto it = container.begin();  // Iterator type is long and not helpful to spell out
+
+    // The return type is std::vector<std::vector<std::pair<int, float>>>
+    auto matrix = generate_adjacency_matrix();
+
+    // Lambdas have unreadable and compiler-generated types — use auto for them
+    auto add = [](int x, int y) { return x + y; };
+
+
+Avoid `auto` when the type is simple and clear:
+
+.. code-block:: cpp
+
+    // Use type names when they are short and readable.
+    for (RRNodeId node_id : device_ctx.rr_graph.nodes()) {
+        t_rr_node_route_inf& node_inf = route_ctx.rr_node_route_inf[rr_id];
+    }
+
+    int count = 0;
+    std::string name = "example";
+    std::vector<int> numbers = {1, 2, 3};
+
+Avoid:
+
+.. code-block:: cpp
+
+    auto count = 0;                // Simple and obvious type
+    auto name = std::string("x");  // Hides a short, clear type
+
+    for (auto node_id : device_ctx.rr_graph.nodes()) {
+        // node_id is RRNodeId. Write it out for clarity.
+        auto& node_inf = route_ctx.rr_node_route_inf[rr_id];
+        // node_inf is t_rr_node_route_inf. Use the explicit type since it's simple and meaningful.
+    }
+
+Rationale: clear, explicit types help with readability and understanding. Avoid hiding simple types behind `auto`.
+
+
+
+Commenting Style
+~~~~~~~~~~~~~~~~
+
+Comments help readers understand the purpose, structure, and reasoning behind the code.
+This section outlines when and how to use comments in a consistent and helpful way.
+
+General Rules
+-------------
+
+- Focus on explaining *why* the code exists or behaves in a certain way.
+- Do not explain *what* the code is doing if it's already clear from the code itself.
+- Keep comments up to date. Outdated comments are worse than no comments.
+- Use Doxygen-style `/** ... */` or `///` for documenting APIs, classes, structs, members, and files.
+
+Comment types and rules:
+
+- Use `/* ... */` **only** for Doxygen documentation comments.
+  Do **not** use block comments (`/* */`) to describe code logic or individual lines in function bodies.
+
+- Use `//` for all regular comments within function bodies or implementation code.
+
+Formatting rules for `//` comments:
+
+- Always include a space between `//` and the comment text.
+- Use full sentences when appropriate.
+- For multi-line comments, prefix each line with `// `.
+
+Incorrect usage:
+
+.. code-block:: cpp
+
+    /* Check if visited */  // Block comments are not allowed here
+    if (visited[node_id]) {
+        return;
+    }
+
+    //Missing space
+    //inconsistent formatting
+
+    /* Non-Doxygen block comment */  // Not permitted
+
+When to Comment
+---------------
+
+**1. File-Level Comments**
+- Every source/header file should begin with a brief comment explaining the overall purpose of the file.
+
+**2. Classes and Structs**
+- Add a comment describing what the class or struct is for.
+- Comment every member variable to explain its role.
+
+Example:
+
+.. code-block:: cpp
+
+    /**
+     * @brief Manages TCP connections for a server.
+     */
+    class ConnectionManager {
+    public:
+        /**
+         * @brief Starts listening for incoming connections.
+         */
+        void Start();
+
+    private:
+        int port_;          ///< Listening port.
+        bool is_running_;   ///< Whether the server is active.
+    };
+
+
+**3. Functions**
+- All non-trivial functions must have a Doxygen comment in the header file or on the static declaration.
+- Explain what the function does, its parameters, and its return value.
+
+Example:
+
+.. code-block:: cpp
+
+    /**
+     * @brief Estimates the wirelength of a net using bounding box.
+     *
+     * @param net_id ID of the net to analyze.
+     * @return Estimated wirelength in units.
+     */
+    float estimate_wirelength(ClusterNetId net_id);
+
+Example:
+
+.. code-block:: cpp
+
+    // Skip ignored nets
+    if (net.is_ignored()) {
+        continue;
+    }
+
+
+
+
+

doc/src/dev/index.rst

@@ -11,5 +11,6 @@ Developer Guide
     c_api_doc
     code_documentation
     tutorials/index
+    coding_style
     ../SUPPORT
     ../LICENSE