doc: update doc

Author: observerw

docs/language-configuration.md

@@ -13,13 +13,17 @@ In the `lsp-client` SDK, language-specific configurations are primarily defined
 - **project_files (`list[str]`)**:
   A list of "marker" files used to identify the project root directory (e.g., `["pyproject.toml", "Cargo.toml", "package.json"]`). When the client attempts to determine the root directory for a file, it searches upwards recursively for directories containing these files.
 - **exclude_files (`list[str]`)**:
-  A list of marker files indicating that a directory should _not_ be considered a project root.
+  A list of marker files indicating that a directory should _not_ be considered a project root. For example, `["venv", ".venv"]` can be used to prevent the client from treating a virtual environment as a project root.
 
 ## Project Root Discovery
 
 The client determines the project root by searching upwards from the given file path until a valid project root is found or the system root is reached. This discovery is based on the `project_files` and `exclude_files` defined in the `LanguageConfig`.
 
-The `LanguageConfig` class provides a `find_project_root(path: Path)` method that combines `suffixes`, `project_files`, and `exclude_files` for precise detection.
+The `LanguageConfig` class provides a `find_project_root(path: Path)` method:
+1. If the path is a file, it first checks if the file suffix matches. If not, it returns `None`.
+2. It then searches upwards for `exclude_files`. If found, it stops and returns `None`.
+3. It searches upwards for `project_files`. If found, it returns the containing directory.
+4. If no markers are found, it returns the original directory (or the file's parent).
 
 ## Client Language Attributes
 
@@ -31,26 +35,49 @@ The `Client` base class includes several general configurations related to langu
   Custom options passed to the server during the `initialize` request. Most Language Servers require specific configurations here to function correctly.
 - **`request_timeout` (float, default `5.0`)**:
   The timeout in seconds for LSP requests.
+- **`create_default_config()`**:
+  An optional method to provide default LSP configuration (settings) for the client. These settings are typically used to configure the Language Server's behavior (e.g., enabling/disabling specific analysis features).
 
 ## Example: Defining a Custom Language Client
 
-To support a new language, you typically inherit from `Client` (or a base class like `PythonClientBase`) and implement the `get_language_config` method:
+To support a new language, you typically inherit from `Client` and implement the required abstract methods:
 
 ```python
-from pathlib import Path
-from typing import override
+from typing import Any, override
 from lsp_client.client.abc import Client
 from lsp_client.client.lang import LanguageConfig
+from lsp_client.server import DefaultServers
 from lsp_client.utils.types import lsp_type
 
 class MyNewLanguageClient(Client):
+    @classmethod
     @override
-    def get_language_config(self) -> LanguageConfig:
+    def get_language_config(cls) -> LanguageConfig:
         return LanguageConfig(
-            kind=lsp_type.LanguageKind.PlainText, # Replace with actual language kind
+            kind=lsp_type.LanguageKind.PlainText,
             suffixes=[".mylang"],
-            project_files=["my_project.config"]
+            project_files=["my_project.config"],
+            exclude_files=[".ignore_me"]
         )
 
-    # Other abstract methods like create_default_servers must also be implemented
+    @override
+    def create_default_servers(self) -> DefaultServers:
+        # Define how to start the server (local or containerized)
+        ...
+
+    @override
+    def check_server_compatibility(self, info: lsp_type.ServerInfo | None) -> None:
+        # Optionally check if the server version/info is compatible
+        pass
+
+    @override
+    def create_default_config(self) -> dict[str, Any] | None:
+        # Provide default LSP settings
+        return {
+            "mylang": {
+                "analysis": {
+                    "enableFeatureX": True
+                }
+            }
+        }
 ```