"Either" and "Maybe" data structures
This library provides two fundamental near-trivial data structures for Python:
- Either also known as “coproduct”, “sum type”, “variant”, “tagged union”, “disjoint union”, etc: A value that comes from one of two sets
- Maybe also known as “option” or “Either Nothing”: A value that may be missing. (Python has “None” but it does not compose)
Each is ~10 lines, mostly boilerplate, but now they are in one place in a library.
If you are unfamiliar with these concepts, here is some reading from around the web:
- [Tagged union (Wikipedia)](http://en.wikipedia.org/wiki/Tagged_union)
- [Either (Scala)](http://www.scala-lang.org/api/current/scala/Either.html)
- [Boost.Variant (C++)](http://www.boost.org/doc/libs/1_50_0/doc/html/variant.html)
- [Data.Either (Haskell)](http://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Either.html)
- [std.variant (D)](http://dlang.org/phobos/std_variant.html)
- [Option (Scala)](http://www.scala-lang.org/api/current/scala/Option.html)
- [Maybe (Java)](https://github.com/npryce/maybe-java)
- [Maybe pattern (Python recipe)](http://code.activestate.com/recipes/577248-maybe-pattern/)
- [Data.Maybe (Haskell)](http://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Maybe.html)
- [Maybe (Ruby)](https://github.com/bhb/maybe)
Copyright and License
Copyright 2012- Kenneth Knowles
Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
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