Data commit

Task/SEDOLs/Python/sedols-1.py

@@ -0,0 +1,25 @@
+def char2value(c):
+  assert c not in 'AEIOU', "No vowels"
+  return int(c, 36)
+
+sedolweight = [1,3,1,7,3,9]
+
+def checksum(sedol):
+    tmp = sum(map(lambda ch, weight: char2value(ch) * weight,
+                  sedol, sedolweight)
+               )
+    return str((10 - (tmp % 10)) % 10)
+
+for sedol in '''
+    710889
+    B0YBKJ
+    406566
+    B0YBLH
+    228276
+    B0YBKL
+    557910
+    B0YBKR
+    585284
+    B0YBKT
+    '''.split():
+    print sedol + checksum(sedol)

Task/SEDOLs/Python/sedols-2.py

@@ -0,0 +1,125 @@
+'''SEDOL checksum digits'''
+
+from functools import reduce
+
+
+# sedolCheckSumDigitLR :: String -> Either String Char
+def sedolCheckSumDigitLR(s):
+    '''Either an explanatory message, or a
+       checksum digit character to append
+       to a given six-character SEDOL string.
+    '''
+    def goLR(lr, cn):
+        c, n = cn
+        return bindLR(lr)(
+            lambda a: bindLR(sedolValLR(c))(
+                lambda x: Right(a + x * n)
+            )
+        )
+    return bindLR(
+        reduce(
+            goLR,
+            zip(s, [1, 3, 1, 7, 3, 9]),
+            Right(0)
+        )
+    )(lambda d: Right(str((10 - (d % 10)) % 10)))
+
+
+# sedolValLR :: Char -> Either String Char
+def sedolValLR(c):
+    '''Either an explanatory message, or the
+       SEDOL value of a given character.
+    '''
+    return Right(int(c, 36)) if (
+        c not in 'AEIOU'
+    ) else Left('Unexpected vowel in SEDOL string: ' + c)
+
+
+# TEST -------------------------------------------------
+def main():
+    '''Append checksums where valid.'''
+
+    print(
+        fTable(__doc__ + ':\n')(str)(
+            either(str)(str)
+        )(sedolCheckSumDigitLR)(
+            '''710889
+               B0YBKJ
+               406566
+               B0YBLH
+               228276
+               B0YBKL
+               BOYBKL
+               557910
+               B0YBKR
+               585284
+               B0YBKT
+               B00030
+            '''.split()
+        )
+    )
+
+
+# GENERIC -------------------------------------------------
+
+
+# Left :: a -> Either a b
+def Left(x):
+    '''Constructor for an empty Either (option type) value
+       with an associated string.'''
+    return {'type': 'Either', 'Right': None, 'Left': x}
+
+
+# Right :: b -> Either a b
+def Right(x):
+    '''Constructor for a populated Either (option type) value'''
+    return {'type': 'Either', 'Left': None, 'Right': x}
+
+
+# bindLR (>>=) :: Either a -> (a -> Either b) -> Either b
+def bindLR(m):
+    '''Either monad injection operator.
+       Two computations sequentially composed,
+       with any value produced by the first
+       passed as an argument to the second.'''
+    return lambda mf: (
+        mf(m.get('Right')) if None is m.get('Left') else m
+    )
+
+
+# compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
+def compose(g):
+    '''Right to left function composition.'''
+    return lambda f: lambda x: g(f(x))
+
+
+# either :: (a -> c) -> (b -> c) -> Either a b -> c
+def either(fl):
+    '''The application of fl to e if e is a Left value,
+       or the application of fr to e if e is a Right value.'''
+    return lambda fr: lambda e: fl(e['Left']) if (
+        None is e['Right']
+    ) else fr(e['Right'])
+
+
+# fTable :: String -> (a -> String) ->
+#                     (b -> String) ->
+#        (a -> b) -> [a] -> String
+def fTable(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()