https://github.com/simonrichardson/binoculars

Monadic Lenses for data
https://github.com/simonrichardson/binoculars

Last synced: 22 days ago
JSON representation

Monadic Lenses for data

• Host: GitHub
• URL: https://github.com/simonrichardson/binoculars
• Owner: SimonRichardson
• License: mit
• Created: 2014-09-11T10:34:51.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2014-10-08T20:08:25.000Z (about 10 years ago)
• Last Synced: 2024-05-01T23:21:22.081Z (6 months ago)
• Language: Go
• Homepage:
• Size: 207 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
binoculars

==========

## Lenses

Monadic Lenses for data

Lenses are composable, immutable getters and setters. Composable in

that they allow updating of nested data structures. Immutable in that

the setters return copies of the whole data structure.

## Examples

The [example](example.go) is a lot more up to date by it's very nature of being 

code, but to give you an idea, see the following:

### Nested updating

```go

type Person struct {

    Name     string

    Location Location

}

type Location struct {

    Number   int

    Street   string

    Postcode int

}

person := Person{

    Name: "Joe Smith",

    Location: Location{

        Number: 1006,

        Street: "Pearl St",

        Postcode: 80302,

    }

}

locationLens = binoculars.ObjectLens('Location'),

numberLens = binoculars.ObjectLens('Number'),

store = locationLens.AndThen(numberLens).Run(person);

console.log(store.Get());

// 1006

console.log(store.Set(1007));

// { Name: 'Joe Smith',

//   Location: { Number: 1007, Street: 'Pearl St', Postcode: 80302, },

// }

```

### Notes

Although some of the structs are named after other functional language types 

(Store, etc), they are not in fact the same. They're close, but each type has

been locked down to a tighter set of types, to prevent the need for type casting.

Which means they'll not pass any monadic laws!!