September Morn Update

Task/Set-consolidation/Python/set-consolidation-4.py

@@ -0,0 +1,73 @@
+'''Set consolidation'''
+
+from functools import (reduce)
+
+
+# consolidated :: Ord a => [Set a] -> [Set a]
+def consolidated(sets):
+    '''A consolidated list of sets.'''
+    def go(xs, s):
+        if xs:
+            h = xs[0]
+            return go(xs[1:], h.union(s)) if (
+                h.intersection(s)
+            ) else [h] + go(xs[1:], s)
+        else:
+            return [s]
+    return reduce(go, sets, [])
+
+
+# TESTS ---------------------------------------------------
+# main :: IO ()
+def main():
+    '''Illustrative consolidations.'''
+
+    print(
+        tabulated('Consolidation of sets of characters:')(
+            lambda x: str(list(map(compose(concat)(list), x)))
+        )(str)(
+            consolidated
+        )(list(map(lambda xs: list(map(set, xs)), [
+            ['ab', 'cd'],
+            ['ab', 'bd'],
+            ['ab', 'cd', 'db'],
+            ['hik', 'ab', 'cd', 'db', 'fgh']
+        ])))
+    )
+
+
+# DISPLAY OF RESULTS --------------------------------------
+
+# compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
+def compose(g):
+    '''Right to left function composition.'''
+    return lambda f: lambda x: g(f(x))
+
+
+# concat :: [String] -> String
+def concat(xs):
+    '''Concatenation of strings in xs.'''
+    return ''.join(xs)
+
+
+# tabulated :: String -> (a -> String) ->
+#                        (b -> String) ->
+#                        (a -> b) -> [a] -> String
+def tabulated(s):
+    '''Heading -> x display function -> fx display function ->
+          f -> value list -> tabular string.'''
+    def go(xShow, fxShow, f, xs):
+        w = max(map(compose(len)(xShow), xs))
+        return s + '\n' + '\n'.join([
+            xShow(x).rjust(w, ' ') + ' -> ' + fxShow(f(x)) for x in xs
+        ])
+    return lambda xShow: lambda fxShow: (
+        lambda f: lambda xs: go(
+            xShow, fxShow, f, xs
+        )
+    )
+
+
+# MAIN ---
+if __name__ == '__main__':
+    main()