Added merge_with

emis_funky_funktions.py

@@ -205,6 +205,18 @@ fst = indx(0)
 snd = indx(1)
 "Get the second element of a tuple/sequence"
 
+def merge_with(conflict: Callable[[B, C], D], m1: Mapping[A, B], m2: Mapping[A, C]) -> Mapping[A, B | C | D]:
+	"""
+	Merge two mappings, handling conflicts with special behaviour.
+
+	>>> merge_with(lambda a, b: a - b, {'a': 10, "b": 20, "c": 30}, {"b": 2, "c": 3, "d": 4}) == {'a': 10, 'b': 18, 'c': 27, 'd': 4}
+	True
+	"""
+	return {
+		key: ((conflict(m1[key], m2[key]) if key in m2 else m1[key]) if key in m1 else m2[key])
+		for key in (m1.keys() | m2.keys())
+	}
+
 # Semantic Editor Combinators
 class SemEdComb:
 	"""