# README

unit

Unit is a library to parse user defined units in go. It was written with sizes in mind, but everything where the numeric part can be converted to an int64 is possible.

It can be used standalone, but also implements the flag interfaces.

Installing

go get -u github.com/rck/unit

Next, include unit in your application:

import "github.com/rck/unit"

Example

package main

import (
	"flag"
	"fmt"
	"log"

	"github.com/rck/unit"
)

func main() {
	size := unit.MustNewUnit(unit.DefaultUnits).MustNewValue(1, unit.None)
	flag.Var(size, "s", "Parse a size")
	flag.Parse()
	fmt.Println(size.Value)

	myUnits := unit.DefaultUnits
	myUnits["kB"] = unit.DefaultUnits["KB"]

	u, err := unit.NewUnit(myUnits)
	if err != nil {
		log.Fatalf("Could not create unit based on mapping: %v\n", err)
	}
	if v, err := u.ValueFromString("+1024K"); err == nil {
		fmt.Println(v.Value, v)
		switch v.ExplicitSign {
		case unit.Positive:
			fmt.Println("Explicit positive sign")
		case unit.Negative:
			fmt.Println("Explicit negative sign")
		case unit.None:
			fmt.Println("No xxplicit sign")
		default:
			fmt.Println("This can not happen :-)")
		}
	}

	// if called with -s 20M, prints:
	// 20971520
	// 1048576 +1M
	// Explicit positive sign
}