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main.go
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main.go
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package main
import (
"fmt"
"os"
"strconv"
"strings"
"github.com/bcicen/go-units"
"github.com/bcicen/xiny/log"
)
var (
version = "dev-build"
build = "unknown"
usageStr = []string{
"usage: xiny [options] [input]\n",
"e.g xiny 20kg in lbs\n",
"options",
}
versionStr = fmt.Sprintf("xiny version %s, build %s", version, build)
displayUnits = true // whether unit label will be displayed in output
)
var opts = []Opt{
{"i", "start xiny in interactive mode", func() { interactive() }},
{"n", "display only numeric output (exclude units)", func() { displayUnits = false }},
{"v", "enable verbose output", func() { log.Level = log.INFO }},
{"vv", "enable debug output", func() { log.Level = log.DEBUG }},
{"version", "print version info and exit", func() { fmt.Println(versionStr); os.Exit(0) }},
}
type Opt struct {
name string
desc string
handler func()
}
func handleOpt(s string) {
if s == "h" || s == "help" {
usage()
}
for _, opt := range opts {
if opt.name == s {
opt.handler()
return
}
}
exitErr(fmt.Errorf("unknown option: -%s", s))
}
func usage() {
var optUsage []string
for _, opt := range opts {
spacing := " "
if len(opt.name) <= 5 {
spacing = " "
}
line := fmt.Sprintf(" -%s%s%s", opt.name, spacing, opt.desc)
optUsage = append(optUsage, line)
}
fmt.Println(strings.Join(append(usageStr, optUsage...), "\n"))
os.Exit(0)
}
func failOnErr(err error, pfix ...string) {
if err != nil {
if len(pfix) != 0 {
err = fmt.Errorf("%s: %s", pfix[0], err)
}
exitErr(err)
}
}
func exitErr(err error) {
log.Error(err)
os.Exit(1)
}
func recovery(exit bool) {
var err error
if r := recover(); r != nil {
switch x := r.(type) {
case string:
err = fmt.Errorf(r.(string))
case error:
err = x
default:
panic(r)
}
log.Error(err)
if exit {
os.Exit(1)
}
}
if exit {
os.Exit(0)
}
}
func doConvert(cmd string) string {
x, fromStr, toStr, err := parseCmd(cmd)
if err != nil {
panic(fmt.Errorf("parse error: %s", err))
}
fromUnit, err := units.Find(fromStr)
if err != nil {
panic(err)
}
toUnit, err := units.Find(toStr)
if err != nil {
panic(err)
}
if fromUnit.Quantity != toUnit.Quantity {
e := fmt.Sprintf("%s -> %s", fromUnit.Quantity, toUnit.Quantity)
panic(fmt.Errorf("unit mismatch: cannot convert %s", e))
}
path, err := units.ResolveConversion(fromUnit, toUnit)
if err != nil {
panic(err)
}
var formula string
for _, conv := range path {
if formula != "" {
formula = fmt.Sprintf("(%s)", strings.Replace(conv.Formula, "x", formula, 1))
} else {
formula = fmt.Sprintf("(%s)", conv.Formula)
}
log.Debugf("%s -> %s: %s", conv.From(), conv.To(), conv.Formula)
x = conv.Fn(x)
}
log.Infof("%s -> %s: %s", fromUnit.Name, toUnit.Name, formula)
if !displayUnits {
return strconv.FormatFloat(x, 'f', 6, 64)
}
return units.NewValue(x, toUnit).String()
}
func main() {
defer recovery(true)
if len(os.Args) <= 1 {
usage()
}
cmd := strings.Join(os.Args[1:], " ")
for _, optName := range parseOpts(&cmd) {
handleOpt(optName)
}
fmt.Println(doConvert(cmd))
}