enh: env: support item/attr deletion

Technologicat · Technologicat · commit ffe011b0f362 · 2019-03-07T10:26:34.000+02:00
diff --git a/unpythonic/env.py b/unpythonic/env.py
@@ -83,6 +83,14 @@ def __getattr__(self, name):
             raise AttributeError("name '{:s}' is not defined".format(name))
         return e[name]
 
+    def __delattr__(self, name):
+        if not name.isidentifier():
+            raise ValueError("'{}' is not a valid identifier".format(name))
+        e = self._env   # __getattr__ not called if direct attr lookup succeeds, no need for hook.
+        if name not in e:
+            raise AttributeError("name '{:s}' is not defined".format(name))
+        del e[name]
+
     # membership test (in, not in)
     def __contains__(self, k):
         return self._env.__contains__(k)
@@ -115,6 +123,9 @@ def __getitem__(self, k):
     def __setitem__(self, k, v):
         setattr(self, k, v)
 
+    def __delitem__(self, k):
+        delattr(self, k)
+
     # context manager
     def __enter__(self):
         return self
