pair

The two-element composite of go-composites. A Pair is a fixed, heterogeneous grouping of two values — the natural key/value entry. It is interface-first and never goes nil: the Null-Object Pair honours the whole Interface.

Install

go get github.com/go-composites/pair

Usage

package main

import (
    "fmt"

    Pair "github.com/go-composites/pair/src"
)

func main() {
    entry := Pair.New("answer", 42)

    fmt.Println(entry.ToGoString())                    // (answer, 42)
    fmt.Println(entry.First())                         // answer
    fmt.Println(entry.Second())                        // 42
    fmt.Println(entry.Equal(Pair.New("answer", 42)))   // true
    fmt.Println(entry.ToArray().Len())                 // 2
}

API

Constructors

• New(first, second interface{}) Interface — a Pair holding the two values.
• Null() Interface — the Null-Object Pair.

Methods

method	returns	notes
First()	interface{}	the first slot
Second()	interface{}	the second slot
Equal(other)	Go bool	both slots reflect.DeepEqual (false against a null Pair)
ToArray()	Array.Interface	a two-element [first, second] Array
ToGoString()	Go string	"(first, second)" ("(null)" for the Null-Object)
IsNull()	Go bool	true only for the Null-Object

Null-Object

Null() returns the never-nil Null-Object Pair: its slots are nil, it Equals nothing (not even another null Pair), ToArray() is the empty Array, and ToGoString() renders "(null)". IsNull() reports true for it.

License

BSD-3-Clause © the go-composites/pair authors.