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https://github.com/phink/changeset
(unreleased) Data validation with first-class and first-order labels in OCaml
https://github.com/phink/changeset
data-validation ocaml
Last synced: 3 months ago
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(unreleased) Data validation with first-class and first-order labels in OCaml
- Host: GitHub
- URL: https://github.com/phink/changeset
- Owner: phink
- License: mit
- Created: 2018-05-23T23:05:40.000Z (over 6 years ago)
- Default Branch: develop
- Last Pushed: 2018-06-29T14:23:20.000Z (over 6 years ago)
- Last Synced: 2024-08-04T01:28:28.817Z (6 months ago)
- Topics: data-validation, ocaml
- Language: OCaml
- Homepage: https://phink.github.io/changeset/changeset_lib/index.html
- Size: 85.9 KB
- Stars: 30
- Watchers: 3
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
- awesome-list - changeset - class and first-order labels in OCaml | phink | 28 | (OCaml)
README
*This is WIP.*
| Service | OCaml | Service |
| ------- | ----- | ------- |
| Circle | 4.06 |[](https://circleci.com/gh/phink/changeset/tree/develop) |
# Changeset
**Data validation with first-class and first-order labels in OCaml.**
Homepage for the library is
[available here](https://phink.github.io/changeset/changeset_lib/index.html).
Changesets are tools to validate data while accumulating errors along the way.
They are composed of:
- **Changes**: an heterogeneous map whose keys are of type `'a label` and
values `'a`.
When deriving a changeset from a record type definition, the labels
correspond to the fields of this one.
- **Errors**: a list of strings associated with labels.
Labels are first-class, that means you can give them as argument to functions,
and first-order, so you can pattern match against them. The library
promotes the pipeline design approach.
There is a ppx deriving plugin so there is no need to write any
boilerplate code.
#### Install using opam
```
$ opam pin add changeset_lib https://github.com/phink/changeset.git
$ opam pin add ppx_changeset https://github.com/phink/changeset.git
```
#### Update the libraries and preprocess section in your jbuild file:
```
(libraries (... changeset))
(preprocess (pps (... ppx_changeset)))
```
### Minimal example
```ocaml
type t = {
age: int;
phone: string;
password: string;
} [@@deriving changeset]
let validate cset =
cset
|> Changeset.validate_int Age [`greater_than_or_equal_to 0]
|> Changeset.validate_string_length Password [`min 12]
|> Changeset.validate_format Phone (Str.regexp "^\\+?[1-9][0-9]+$")
let create t =
let cset = Changeset.from_record t in
Changeset.apply (validate cset)
let data = {age = 12; password = "dolphin"; phone = "+14155552671"}
let () = match create data with
| Ok t -> (* do what you want *)
| Error cset ->
Stdio.prerr_endline (Changeset.show_errors cset)
```
Execution
```json
{
"errors":{
"password":"should be at least 12 character(s)"
}
}
```
### Limitations
Parameterized source types are not yet supported.