Awesome

redo

redo is like make, but better.

Like make, redo allows you to rebuild source files when they have changed. But unlike make, redo is simple, easy to learn, and flexible. redo exhibits its power the Unix way, by leveraging other tools. Build scripts for redo are simply shell scripts which follow a few conventions. If you don't like shell, redo also supports any language that can be run with a shebang (!#), ie. python, perl, etc.

While I wrote this implementation of redo, credit for the original design goes to D. J. Bernstein, who published its design in a set of notes on his website. Since djb has never released his version of redo, a few people have created and published their own implementations. Before writing this implementation, I used Avery Pennarun's python implementation on a daily basis in my projects. Later, I found Chris Forno's video series on implementing redo from scratch in Haskell. I was intrigued at the prospect of implementing an elegant program in an elegant language, and so I began implementing my own version of redo in Haskell. The end result is this version of redo, which looks and feels very similiar to apenwarr's implementation, but fixes some annoying bugs, and may run a bit faster.

I intend to continue maintaining and improving this implementation of redo for the forseeable future. If you encounter any problems, feel free to submit a pull request or post an issue. I continue to use this version of redo every day.

Compilation and Installation

To build redo, first make sure you have the Haskell Tool Stack installed.

Next, clone this repository and run:

./do

in the top level directory. A bin/ directory will be created with the redo, redo-ifchange, redo-ifcreate, and redo-always binaries. Add this bin/ directory to your path, or copy its contents to a directory on your path, and enjoy!

If you want to try redo without compiling, there is a Dockerfile available with redo preinstalled. This container also contains the Haskell Stack if you want to make modifications and recompile.

Documentation

I try to keep this implementation compatible with Avery Pennarun's Python implementation, plus some bug fixes, and extra features documented in redo -h. Thus, the best documentation on redo that exists is Avery's documentation via readthedocs.org

Note that redo's database is stored in ~/.redo. If redo ever gets confused for some reason, you can always reset its state by cleaning your project, running rm -r ~/.redo, and running your redo command again.

Credits

D. J. Bernstein conceived the idea behind redo and wrote some notes at http://cr.yp.to/redo.html.

I first became interested in redo after using Avery Pennarun's Python implementation to build my own projects.

Chris Forno created a fantastic on-camera implementation of redo in Haskell which served as the inspiration for this implementation.