edit: A monad for rewriting things.
Flags
Manual Flags
| Name | Description | Default |
|---|---|---|
| no_arbitrary | Removes QuickCheck as a dependency (so no Arbitrary instance is provided). | Disabled |
| no_comonad | Removes comonad as a dependency (so no Comonad instance is provided). | Disabled |
| tutorial | Build the tutorial. Adds dependencies on uniplate and containers. | Disabled |
Use -f <flag> to enable a flag, or -f -<flag> to disable that flag. More info
Downloads
- edit-1.0.1.0.tar.gz [browse] (Cabal source package)
- Package description (as included in the package)
Maintainer's Corner
For package maintainers and hackage trustees
Candidates
| Versions [RSS] | 0.0.1.0, 0.0.1.1, 1.0.0.0, 1.0.1.0 |
|---|---|
| Change log | ChangeLog.md |
| Dependencies | base (>=4.9 && <4.12), comonad, deepseq (>=1.1 && <1.5), QuickCheck (>=2.10 && <2.13), transformers (>=0.5 && <0.6) [details] |
| License | BSD-3-Clause |
| Copyright | Varun Gandhi 2018 |
| Author | Varun Gandhi <theindigamer15@gmail.com> |
| Maintainer | Varun Gandhi <theindigamer15@gmail.com> |
| Category | Data |
| Home page | https://github.com/theindigamer/edit |
| Source repo | head: git clone https://github.com/theindigamer/edit.git |
| Uploaded | by theindigamer at 2018-09-03T14:16:10Z |
| Distributions | |
| Reverse Dependencies | 1 direct, 0 indirect [details] |
| Downloads | 2303 total (4 in the last 30 days) |
| Rating | (no votes yet) [estimated by Bayesian average] |
| Your Rating | |
| Status | Docs available [build log] Last success reported on 2018-09-03 [all 1 reports] |
Readme for edit-1.0.1.0
[back to package description]Edit 
The Edit monad allows you to easily bubble up whether a change was made or not when rewriting things. Some cases where this can be handy:
- You are making a sequence of transformations on some type and want to keep track of whether any of them changed it or not.
- You are rewriting a recursive type (or a garden of mutually recursive types!) and want to bubble up information whether something was changed or not.
For example, Reddit user /u/p__bing says
[..] I work as an iOS developer and we have this same exact idea implemented, as a monad, in Swift, to make our UI updates faster (if a change goes through our model layer and comes out Clean, we don’t bother touching the UI).
A small example:
>>> halveEvens x = if x `mod` 2 == 0 then (Dirty $ x `div` 2) else (Clean x) >>> traverse halveEvens [1, 2, 3] Dirty [1,1,3] >>> traverse halveEvens [1, 3, 5] Clean [1,3,5] More thorough documentation is available on Hackage under the Data.Edit module. There is a tutorial too under Data.Edit.Tutorial.
There is also a corresponding monad transformer EditT available under Control.Monad.Trans.EditT.
Contributing
Please open an issue on the Github issue tracker to discuss missing documentation, API changes etc.