Data commit

Task/Function-composition/Python/function-composition-1.py

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+compose = lambda f, g: lambda x: f( g(x) )

Task/Function-composition/Python/function-composition-2.py

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+>>> compose = lambda f, g: lambda x: f( g(x) )
+>>> from math import sin, asin
+>>> sin_asin = compose(sin, asin)
+>>> sin_asin(0.5)
+0.5
+>>>

Task/Function-composition/Python/function-composition-3.py

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+from math import (acos, cos, asin, sin)
+
+
+# compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
+def compose(g, f):
+    '''Right to left function composition.'''
+    return lambda x: g(f(x))
+
+
+# main :: IO ()
+def main():
+    '''Test'''
+
+    print(list(map(
+        lambda f: f(0.5),
+        zipWith(compose)(
+            [sin, cos, lambda x: x ** 3.0]
+        )([asin, acos, lambda x: x ** (1 / 3.0)])
+    )))
+
+
+# GENERIC FUNCTIONS ---------------------------------------
+
+
+# zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
+def zipWith(f):
+    '''A list constructed by zipping with a
+       custom function, rather than with the
+       default tuple constructor.'''
+    return lambda xs: lambda ys: (
+        map(f, xs, ys)
+    )
+
+
+if __name__ == '__main__':
+    main()

Task/Function-composition/Python/function-composition-4.py

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+from functools import reduce
+from math import sqrt
+
+
+def compose(*fs):
+    '''Composition, from right to left,
+       of an arbitrary number of functions.
+    '''
+    def go(f, g):
+        return lambda x: f(g(x))
+
+    return reduce(go, fs, lambda x: x)
+
+
+# ------------------------- TEST -------------------------
+def main():
+    '''Composition of three functions.'''
+
+    f = compose(
+        half,
+        succ,
+        sqrt
+    )
+
+    print(
+        f(5)
+    )
+
+
+# ----------------------- GENERAL ------------------------
+def half(n):
+    return n / 2
+
+
+def succ(n):
+    return 1 + n
+
+
+if __name__ == '__main__':
+    main()

Task/Function-composition/Python/function-composition-5.py

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+# Contents of `pip install compositions'
+
+class Compose(object):
+    def __init__(self, func):
+        self.func = func
+
+    def __call__(self, x):
+        return self.func(x)
+
+    def __mul__(self, neighbour):
+        return Compose(lambda x: self.func(neighbour.func(x)))
+
+# from composition.composition import Compose
+if __name__ == "__main__":
+    # Syntax 1
+    @Compose
+    def f(x):
+        return x
+
+    # Syntax 2
+    g = Compose(lambda x: x)
+
+    print((f * g)(2))