# sieve

Generic, dependency-free collection helpers that the standard library slices and maps packages lack: mapping, filtering, reducing, keying, grouping, deduplicating, partitioning and finding, plus a small set type.

`import "git.golem15.com/golem15/summercms/modules/sieve"`

**Name:** A sand sieve: you shake a collection through it and keep what you need; map, filter and reduce for slices and maps.

## Overview

`sieve` gives plain Go slices the collection operations that WinterCMS code reaches for on Laravel collections. Every function is eager and never modifies its input, results never share a backing array with the input, callbacks run once per element in input order, and nil or empty input yields a non-nil empty result, so `encoding/json` writes `[]` rather than `null`.

## Role in the framework

A dependency-free leaf with no imports, so any module, plugin or application can use it without import cycles.

## Features

- `sieve.Map` applies a function to every element and returns the results in order; with a field accessor it is the pluck operation.

## Usage

```go
package blog

import "git.golem15.com/golem15/summercms/modules/sieve"

type Post struct {
	ID    int
	Title string
}

func titles(posts []Post) []string {
	return sieve.Map(posts, func(p Post) string { return p.Title })
}
```

## API reference

| Identifier | Description |
|------------|-------------|
| `sieve.Map` | Returns f applied to each element, in input order. Nil input gives a non-nil empty slice. |

## Dependencies

- SummerCMS modules: none.
- Third-party: none.
- Standard library: none (the package has no imports).

## Testing

```sh
go test ./modules/sieve/...
```

The tests are in-memory and need no external services.