You could do this with a macro, but... the best macro is a macro you don't maintain

datum is a pure functional and generic programming for Erlang. It had its origins in Purely Functional Data Structures by Chris Okasaki, on implementing a various higher rank functional abstractions and patterns, on dealing with scrap your boilerplate and gaining experience from other functional languages primary Scala and Haskell. The library is still testing the limits of functional abstractions in Erlang.

The feature overview provides an introduction to datum features, use-cases and reasoning of they existence:

• data structures with common behavior: foldable, traversable and map-like including
• pure functional data types: binary search tree, red-black tree, heap, queues, streams and others
• resembles concept of getters and setters (lenses) for complex algebraic data types
• define a category pattern and monads

The latest version of the library is available at its master branch. All development, including new features and bug fixes, take place on the master branch using forking and pull requests as described in contribution guidelines.

The stable library release is available via hex packages, add the library as dependency to rebar.config

{deps, [{datum}]}.

The library is Apache 2.0 licensed and accepts contributions via GitHub pull requests:

• Fork the repository on GitHub
• Read build instructions
• Make a pull request

The build process requires Erlang/OTP version 19.0 or later and essential build tools.

Build and run service in your development console. The following command boots Erlang virtual machine and opens Erlang shell.

git clone https://github.com/fogfish/datum
cd datum
make
make run

The commit message helps us to write a good release note, speed-up review process. The message should address two question what changed and why. The project follows the template defined by chapter Contributing to a Project of Git book.

Short (50 chars or less) summary of changes

More detailed explanatory text, if necessary. Wrap it to about 72 characters or so. In some contexts, the first line is treated as the subject of an email and the rest of the text as the body. The blank line separating the summary from the body is critical (unless you omit the body entirely); tools like rebase can get confused if you run the two together.

Further paragraphs come after blank lines.

Bullet points are okay, too

Typically a hyphen or asterisk is used for the bullet, preceded by a single space, with blank lines in between, but conventions vary here

If you experience any issues with the library, please let us know via GitHub issues. We appreciate detailed and accurate reports that help us to identity and replicate the issue.

• Specify the configuration of your environment. Include which operating system you use and the versions of runtime environments.

• Attach logs, screenshots and exceptions, in possible.

• Reveal the steps you took to reproduce the problem, include code snippet or links to your project.

The library uses semantic versions to identify stable releases.

• 4.1.x - Update interface(s) documentation
• 4.0.x - Re-implement monads through Kleisli category
• 3.7.x - Introduce category pattern
• 3.4.x - Improve monads for usage in production
• 3.3.x - Van Laahorven lenses and monads
• 2.7.x - enhance pure functional data-types with abstract interfaces such Foldable, Collections, etc
• 0.9.x - implement pure functional data-types: trees, queues, streams, etc

Copyright 2012 Dmitry Kolesnikov

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 http://www.apache.org/licenses/LICENSE-2.0.

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.