Use pattern matching to do the WHPName lookup in __getitem__ of the _WHPNames object

Author: DocOtak

CHANGELOG

@@ -1,4 +1,4 @@
-v2025.??.0 (2026-??-??)
+v2026.??.0 (2026-??-??)
 =======================
 Parameter Changes
 -----------------
@@ -10,6 +10,7 @@ API Changes
 * (Potentially Breaking) Rise a `ValueError` when attempting to coerce a parameter into an error name when an error name it not defined for it
 * Add typing to WHPNames and CFStandardNames objects
 * Drop python 3.11 support (SPEC 0)
+* Use pattern matching to do the WHPName lookup in `__getitem__` of the `_WHPNames` object
 
 v2025.10.0 (2025-10-31)
 =======================

src/cchdo/params/__init__.py

@@ -201,6 +201,22 @@ def __getitem__(self, key: WHPNameKey | WHPName) -> WHPName:
         error = False
         (name, unit), flag = normalize_whp_name_key(key)
 
+        match key:
+            case str(matched):
+                name, flag = flag_name(matched)
+                name, unit = normalize_odv_name(name, return_parts=True)
+            case tuple((str(name),)):
+                name = name
+            case tuple((str(name), str(unit))):
+                name = name
+                unit = unit
+            case tuple((str(name), None)):
+                name = name
+            case WHPName() as key:
+                name, unit = key.full_whp_name, key.whp_unit
+            case _ as err:
+                raise KeyError(f"whpname keys must be str or a tuple, found {err}")
+
         alias_key = None
         if (name, unit) in self._aliases:
             alias_key = (name, unit)

src/cchdo/params/core.py

@@ -141,7 +141,7 @@ def as_base(self) -> "WHPName":
         return replace(self, flag_col=False, error_col=False, alt_depth=0)
 
     @property
-    def full_whp_name(self):
+    def full_whp_name(self) -> str:
         if self.alt_depth > 0:
             return f"{self.whp_name}_ALT_{self.alt_depth}"
         else: