Add documents for godoc (#15)

internal/option/config.go

@@ -1,3 +1,4 @@
+// Package option provides utilities of option handling
 package option
 
 import (
@@ -6,18 +7,21 @@ import (
 	"github.com/spf13/viper"
 )
 
+// Flag represents flag which can be specified
 type Flag struct {
 	IsPersistent bool
 	Shorthand    string
 	Name         string
 	Usage        string
 }
 
+// StringFlag represents flag which can be specified as string
 type StringFlag struct {
 	*Flag
 	Value string
 }
 
+// BoolFlag represents flag which can be specified as bool
 type BoolFlag struct {
 	*Flag
 	Value bool
@@ -31,6 +35,7 @@ func getFlagSet(cmd *cobra.Command, flagConfig *Flag) (flagSet *pflag.FlagSet) {
 	}
 }
 
+// RegisterStringFlag register string flag to provided cmd and viper
 func RegisterStringFlag(cmd *cobra.Command, flagConfig *StringFlag) error {
 	flagSet := getFlagSet(cmd, flagConfig.Flag)
 	if flagConfig.Shorthand == "" {
@@ -45,6 +50,7 @@ func RegisterStringFlag(cmd *cobra.Command, flagConfig *StringFlag) error {
 	return nil
 }
 
+// RegisterBoolFlag register bool flag to provided cmd and viper
 func RegisterBoolFlag(cmd *cobra.Command, flagConfig *BoolFlag) error {
 	flagSet := getFlagSet(cmd, flagConfig.Flag)
 	if flagConfig.Shorthand == "" {

internal/selfupdate/selfupdate.go

@@ -1,3 +1,4 @@
+// Package selfupdate provides function to update binary
 package selfupdate
 
 import (
@@ -9,6 +10,7 @@ import (
 const Version = "1.2.3"
 const slug = "mpppk/cli-template"
 
+// Do execute updating binary
 func Do() (bool, error) {
 	v := semver.MustParse(Version)
 	latest, err := selfupdate.UpdateSelf(v, slug)

pkg/sum/sum.go

@@ -1,17 +1,20 @@
+// Package sum provides utilities for calculate sum of numbers
 package sum
 
 import (
 	"github.com/mpppk/cli-template/pkg/util"
 	"math"
 )
 
+// Sum returns sum of numbers
 func Sum(numbers []int) (sum int) {
 	for _, number := range numbers {
 		sum += number
 	}
 	return
 }
 
+// L1Norm returns L1 norm of numbers
 func L1Norm(numbers []int) (l1norm int) {
 	var absNumbers []int
 	for _, number := range numbers {
@@ -20,6 +23,7 @@ func L1Norm(numbers []int) (l1norm int) {
 	return Sum(absNumbers)
 }
 
+// SumFromString returns sum numbers which be converted from strings
 func SumFromString(stringNumbers []string) (sum int, err error) {
 	numbers, err := util.ConvertStringSliceToIntSlice(stringNumbers)
 	if err != nil {

pkg/util/util.go

@@ -1,13 +1,13 @@
+// Package util provides some utilities
 package util
 
 import (
-	"fmt"
-	"os"
 	"strconv"
 
 	"golang.org/x/xerrors"
 )
 
+// ConvertStringSliceToIntSlice converts string slices to int slices.
 func ConvertStringSliceToIntSlice(stringSlice []string) (intSlice []int, err error) {
 	for _, s := range stringSlice {
 		num, err := strconv.Atoi(s)
@@ -18,13 +18,3 @@ func ConvertStringSliceToIntSlice(stringSlice []string) (intSlice []int, err err
 	}
 	return
 }
-
-func EPrintlnIFErrExist(err error, msg string) (bool, error) {
-	if err != nil {
-		if _, err := fmt.Fprintln(os.Stderr, msg); err != nil {
-			return true, err
-		}
-		return true, nil
-	}
-	return false, nil
-}