Add a method for getting the schema by name

The schema class can be retrieved using a static method. This fixes
some minor typing errors as well in the cli.validate function.

python/felis/cli.py

@@ -24,7 +24,7 @@
 import logging
 import sys
 from collections.abc import Iterable, Mapping, MutableMapping
-from typing import Any
+from typing import Any, Type
 
 import click
 import yaml
@@ -39,7 +39,7 @@
 from .sql import SQLVisitor
 from .tap import Tap11Base, TapLoadingVisitor, init_tables
 from .utils import ReorderingVisitor
-from .validation import RspSchema
+from .validation import get_schema
 
 logger = logging.getLogger("felis")
 
@@ -313,11 +313,7 @@ def merge(files: Iterable[io.TextIOBase]) -> None:
 @click.argument("files", nargs=-1, type=click.File())
 def validate(schema_name: str, files: Iterable[io.TextIOBase]) -> None:
     """Validate one or more felis YAML files."""
-    if schema_name == "RSP":
-        schema_class = RspSchema
-    else:
-        schema_class = Schema
-
+    schema_class: Type[Schema] = get_schema(schema_name)
     logger.info(f"Using schema {schema_class.__name__}")
 
     rc = 0

python/felis/validation.py

@@ -20,6 +20,7 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import logging
+from typing import Type
 
 from pydantic import Field, conlist, model_validator
 
@@ -89,3 +90,13 @@ def check_tap_table_indexes(cls, sch: "RspSchema") -> "RspSchema":
                     raise ValueError(f"Duplicate 'tap:table_index' value {table_index} found in schema")
                 table_indicies.add(table_index)
         return sch
+
+
+def get_schema(schema_name: str) -> Type[Schema]:
+    """Get the schema class for the given name."""
+    if schema_name == "default":
+        return Schema
+    elif schema_name == "RSP":
+        return RspSchema
+    else:
+        raise ValueError(f"Unknown schema name '{schema_name}'")