Merge pull request RustPython#1134 from RustPython/coolreader18/collections-defaultdict

windelbouwman · web-flow · commit 3c9045d3da05 · 2019-07-11T07:11:31.000+02:00
Add defaultdict to collections; add pprint.py
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
@@ -1277,3 +1277,9 @@ def translate(self, *args):
         return self.__class__(self.data.translate(*args))
     def upper(self): return self.__class__(self.data.upper())
     def zfill(self, width): return self.__class__(self.data.zfill(width))
+
+# FIXME: try to implement defaultdict in collections.rs rather than in Python
+# I (coolreader18) couldn't figure out some class stuff with __new__ and
+# __init__ and __missing__ and subclassing built-in types from Rust, so I went
+# with this instead.
+from ._defaultdict import *
diff --git a/Lib/collections/_defaultdict.py b/Lib/collections/_defaultdict.py
@@ -0,0 +1,20 @@
+class defaultdict(dict):
+    def __new__(cls, *args, **kwargs):
+        if len(args) >= 1:
+            default_factory = args[0]
+            args = args[1:]
+        else:
+            default_factory = None
+        self = dict.__new__(cls, *args, **kwargs)
+        self.default_factory = default_factory
+        return self
+
+    def __missing__(self, key):
+        if self.default_factory:
+            return self.default_factory()
+        else:
+            raise KeyError(key)
+
+    def __repr__(self):
+        return f"defaultdict({self.default_factory}, {dict.__repr__(self)})"
+
diff --git a/Lib/pprint.py b/Lib/pprint.py
