Add readme

Author: tomas-novotny

README.md

@@ -0,0 +1,151 @@
+# Extra
+
+[![Latest Stable Version][ico-release]][link-release]
+[![Build Status][ico-workflow]][link-workflow]
+[![Coverage Status][ico-coverage]][link-coverage]
+[![Go Report Card][ico-go-report-card]][link-go-report-card]
+[![Go Dev Reference][ico-go-dev-reference]][link-go-dev-reference]
+[![Software License][ico-license]][link-licence]
+
+Collection of extra packages that implement some useful features that are missing in the standard library.
+
+
+## Installation
+
+```bash
+go get github.com/gravitton/x
+```
+
+
+## Usage
+
+### Heap
+
+Generic Heap backed by slice implementation using `container/heap` package from existing [proposal](https://github.com/golang/go/issues/47632).
+
+```go
+package main
+
+import (
+	"cmp"
+	"fmt"
+
+	"github.com/gravitton/x/container/heap"
+)
+
+
+type priorityItem struct {
+	  value    string
+	  priority int
+	  index    int
+}
+
+func (i *priorityItem) Compare(item *priorityItem) int {
+	  return cmp.Compare(i.priority, item.priority)
+}
+
+func (i *priorityItem) setIndex(index int) {
+	  i.index = index
+}
+
+func main() {
+	  pq := heap.NewComparable[priorityItem]()
+	  pq.SetIndex((*priorityItem).setIndex)
+
+	  pq.Push(&priorityItem{value: "banana", priority: 3})
+	  pq.Push(&priorityItem{value: "apple", priority: 2})
+	  pq.Push(&priorityItem{value: "pear", priority: 4})
+
+    orange := &priorityItem{value: "orange", priority: 1}
+    pq.Push(orange)
+    orange.priority = 5
+    pq.Fix(orange.index)
+
+	  for pq.Len() > 0 {
+		    item := pq.Pop()
+		    fmt.Printf("%.2d:%s\n", item.priority, item.value)
+	  }
+	  
+	  // 02:apple 03:banana 04:pear 05:orange
+}
+```
+
+### Queue
+
+Generic queue implementation. It is just a wrapper around `[]T` with some extra methods.
+
+```go
+package main
+
+import (
+	"fmt"
+
+	"github.com/gravitton/x/container/queue"
+)
+
+func main() {
+	  q := queue.New[int]()
+	  q.Push(2)
+	  q.Push(3)
+	  q.Push(1)
+
+	  for q.Len() > 0 {
+		    val := q.Pop()
+		    fmt.Println(val)
+	  }
+
+	  // 2 3 1
+}
+```
+
+### Map
+
+Generic Map method for slices.
+
+```go
+package main
+
+import (
+	"fmt"
+	"math"
+
+	"github.com/gravitton/x/slices"
+)
+
+func main() {
+	  sf := slices.Map([]float64{1.1, 2.6, 3.4}, math.Round)
+	  si := slices.Map(sf, func(x float64) int {
+		    return 10 + int(x)
+	  })
+
+	  fmt.Println(si)
+	  // [11, 13, 13]
+}
+```
+## Credits
+
+- [Tomáš Novotný](https://github.com/tomas-novotny)
+- [All Contributors][link-contributors]
+
+
+## License
+
+The MIT License (MIT). Please see [License File][link-licence] for more information.
+
+
+[ico-license]:              https://img.shields.io/github/license/gravitton/x.svg?style=flat-square&colorB=blue
+[ico-workflow]:             https://img.shields.io/github/actions/workflow/status/gravitton/x/main.yml?branch=main&style=flat-square
+[ico-release]:              https://img.shields.io/github/v/release/gravitton/x?style=flat-square&colorB=blue
+[ico-go-dev-reference]:     https://img.shields.io/badge/go.dev-reference-blue?style=flat-square
+[ico-go-report-card]:       https://goreportcard.com/badge/github.com/gravitton/x?style=flat-square
+[ico-coverage]:             https://img.shields.io/coverallsCoverage/github/gravitton/x?style=flat-square
+
+[link-author]:              https://github.com/gravitton
+[link-release]:             https://github.com/gravitton/x/releases
+[link-contributors]:        https://github.com/gravitton/x/contributors
+[link-licence]:             ./LICENSE.md
+[link-changelog]:           ./CHANGELOG.md
+[link-workflow]:            https://github.com/gravitton/x/actions
+[link-go-dev-reference]:    https://pkg.go.dev/github.com/gravitton/x
+[link-go-report-card]:      https://goreportcard.com/report/github.com/gravitton/x
+[link-coverage]:            https://coveralls.io/github/gravitton/x

container/heap/heap_example_test.go

@@ -34,9 +34,12 @@ func ExampleHeap_priorityQueue() {
 
 	for pq.Len() > 0 {
 		item := pq.Pop()
-		fmt.Printf("%.2d:%s ", item.priority, item.value)
+		fmt.Printf("%.2d:%s\n", item.priority, item.value)
 	}
 
 	// Output:
-	// 02:apple 03:banana 04:pear 05:orange
+	// 02:apple
+	// 03:banana
+	// 04:pear
+	// 05:orange
 }