Add infix version of map (#28)

Author: dbrattli

oslash/maybe.py

@@ -66,6 +66,19 @@ def reducer(a, b):
 
         return reduce(reducer, xs, cls.empty())
 
+    def __rmod__(self, fn):
+        """Infix version of map.
+
+        Haskell: <$>
+
+        Example:
+        >>> (lambda x: x+2) % Just(40)
+        42
+
+        Returns a new Functor.
+        """
+        return self.map(fn)
+
 
 class Just(Maybe[TSource]):
     """A Maybe that contains a value.

setup.py

@@ -31,6 +31,7 @@
         'License :: OSI Approved :: MIT License',
         'Operating System :: OS Independent',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
         'Topic :: Software Development :: Libraries :: Python Modules',
     ],
     install_requires=['typing_extensions'],