Initial data commit

Task/Cantor-set/Python/cantor-set-3.py

@@ -0,0 +1,71 @@
+'''Cantor set – strings as both model and display.'''
+
+from itertools import (chain, islice)
+
+
+# cantorLines :: Int -> String
+def cantorLines(n):
+    '''N levels of cantor segmentation,
+       obtained and displayed in the
+       form of lines of block characters.
+    '''
+    return '\n'.join(
+        [''.join(x) for x in islice(
+            iterate(cantor)(
+                [3 ** (n - 1) * '█']
+            ), n
+        )]
+    )
+
+
+# cantor :: [String] -> [String]
+def cantor(xs):
+    '''A cantor line derived from its predecessor.'''
+    def go(s):
+        m = len(s) // 3
+        blocks = s[0:m]
+        return [
+            blocks, m * ' ', blocks
+        ] if '█' == s[0] else [s]
+    return concatMap(go)(xs)
+
+
+# MAIN ----------------------------------------------------
+# main :: IO ()
+def main():
+    '''Testing cantor line generation to level 5'''
+
+    print(
+        cantorLines(5)
+    )
+
+# GENERIC -------------------------------------------------
+
+
+# concatMap :: (a -> [b]) -> [a] -> [b]
+def concatMap(f):
+    '''A concatenated list over which a function has been mapped.
+       The list monad can be derived by using a function f which
+       wraps its output in a list,
+       (using an empty list to represent computational failure).'''
+    return lambda xs: list(
+        chain.from_iterable(map(f, xs))
+    )
+
+
+# iterate :: (a -> a) -> a -> Gen [a]
+def iterate(f):
+    '''An infinite list of repeated
+       applications of f to x.
+    '''
+    def go(x):
+        v = x
+        while True:
+            yield v
+            v = f(v)
+    return lambda x: go(x)
+
+
+# MAIN ---
+if __name__ == '__main__':
+    main()