measurestack: Intern QNames and BaseNames

1 files changed, 30 insertions, 7 deletions

diff --git a/build-aux/measurestack/analyze.py b/build-aux/measurestack/analyze.py
index 0fb20ef..a5ac6e5 100644
--- a/build-aux/measurestack/analyze.py
+++ b/build-aux/measurestack/analyze.py
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
 import re
+import sys
 import typing
 
 from . import vcg
@@ -22,12 +23,23 @@ __all__ = [
 
 
 class BaseName:
-    _content: str
+    # class ##########################################################
+
+    _interned: dict[str, "BaseName"] = {}
 
-    def __init__(self, content: str) -> None:
+    def __new__(cls, content: str) -> "BaseName":
         if ":" in content:
             raise ValueError(f"invalid non-qualified name: {content!r}")
-        self._content = content
+        content = sys.intern(content)
+        if content not in cls._interned:
+            self = super().__new__(cls)
+            self._content = content
+            cls._interned[content] = self
+        return cls._interned[content]
+
+    # instance #######################################################
+
+    _content: str
 
     def __str__(self) -> str:
         return self._content
@@ -55,13 +67,24 @@ class BaseName:
 
 
 class QName:
+    # class ##########################################################
+
+    _interned: dict[str, "QName"] = {}
+
+    def __new__(cls, content: str) -> "QName":
+        content = sys.intern(content)
+        if content not in cls._interned:
+            self = super().__new__(cls)
+            self._content = content
+            self._base = None
+            cls._interned[content] = self
+        return cls._interned[content]
+
+    # instance #######################################################
+
     _content: str
     _base: BaseName | None
 
-    def __init__(self, content: str) -> None:
-        self._content = content
-        self._base = None
-
     def __str__(self) -> str:
         return self._content