refactor: store option short name as byte instead of string

Author: steverusso

builder.go

@@ -76,9 +76,9 @@ func (c *CommandInfo) prepareAndValidate() {
 	for i := 0; i < len(c.Opts)-1; i++ {
 		for z := i + 1; z < len(c.Opts); z++ {
 			// assert there are no duplicate long or short option names
-			if c.Opts[i].NameShort != "" && c.Opts[i].NameShort == c.Opts[z].NameShort {
+			if c.Opts[i].NameShort != 0 && c.Opts[i].NameShort == c.Opts[z].NameShort {
 				panic("command '" + strings.Join(c.Path, " ") +
-					"' contains duplicate option short name '" + c.Opts[i].NameShort + "'")
+					"' contains duplicate option short name '" + string(c.Opts[i].NameShort) + "'")
 			}
 			if c.Opts[i].NameLong != "" && c.Opts[i].NameLong == c.Opts[z].NameLong {
 				panic("command '" + strings.Join(c.Path, " ") +
@@ -149,7 +149,7 @@ func (c CommandInfo) Usage(lines ...string) CommandInfo {
 // pattern starting with the [NewOpt] function or its siblings).
 func (c CommandInfo) Opt(o InputInfo) CommandInfo {
 	// Assert `o` is not a positional arg by making sure it has at least one option name.
-	if o.NameShort == "" && o.NameLong == "" {
+	if o.NameShort == 0 && o.NameLong == "" {
 		panic(errEmptyOptNames)
 	}
 	c.Opts = append(c.Opts, o)
@@ -254,7 +254,7 @@ func (in InputInfo) WithParser(vp ValueParser) InputInfo {
 // Short sets this option's short name to the given character. In order to create an
 // option that has a short name but no long name, see [InputInfo.ShortOnly].
 func (in InputInfo) Short(c byte) InputInfo {
-	in.NameShort = string(c)
+	in.NameShort = c
 	return in
 }
 
@@ -315,5 +315,5 @@ func (in InputInfo) WithHelpGen(hg HelpGenerator) InputInfo {
 }
 
 func (in *InputInfo) isOption() bool {
-	return in.NameShort != "" || in.NameLong != ""
+	return in.NameShort != 0 || in.NameLong != ""
 }

cli.go

@@ -108,7 +108,7 @@ type CommandInfo struct {
 
 type InputInfo struct {
 	ID         string
-	NameShort  string
+	NameShort  byte
 	NameLong   string
 	HelpBlurb  string
 	EnvVar     string
@@ -293,7 +293,7 @@ func (h HelpRequestError) Error() string {
 	return h.HelpMsg
 }
 
-func lookupOptionByShortName(in *CommandInfo, shortName string) *InputInfo {
+func lookupOptionByShortName(in *CommandInfo, shortName byte) *InputInfo {
 	for i := range in.Opts {
 		if in.Opts[i].NameShort == shortName {
 			return &in.Opts[i]
@@ -392,7 +392,7 @@ func parse(c *CommandInfo, p *Command, args []string) error {
 		// which would be handled by the rest of the option parsing code in this loop.
 		if arg[0] != '-' && len(arg) > 1 && arg[1] != '=' {
 			for charIdx := range arg {
-				optName := string(arg[charIdx])
+				optName := arg[charIdx]
 				optInfo := lookupOptionByShortName(c, optName)
 				if optInfo == nil {
 					return UnknownOptionError{Name: "-" + string(arg[charIdx])}
@@ -411,17 +411,17 @@ func parse(c *CommandInfo, p *Command, args []string) error {
 						if i < len(args) {
 							rawValue = args[i]
 						} else {
-							return MissingOptionValueError{Name: optName}
+							return MissingOptionValueError{Name: string(optName)}
 						}
 					} else {
 						rawValue = arg[charIdx+1:]
 						skipRest = true
 					}
 				}
 
-				pi, err := newInput(optInfo, ParsedFrom{Opt: optName}, rawValue)
+				pi, err := newInput(optInfo, ParsedFrom{Opt: string(optName)}, rawValue)
 				if err != nil {
-					return fmt.Errorf("parsing option '%s': %w", optName, err)
+					return fmt.Errorf("parsing option '%c': %w", optName, err)
 				}
 
 				if optInfo.HelpGen != nil {
@@ -461,10 +461,14 @@ func parse(c *CommandInfo, p *Command, args []string) error {
 		}
 
 		var optInfo *InputInfo
-		for i := range c.Opts {
-			if name == c.Opts[i].NameShort || name == c.Opts[i].NameLong {
-				optInfo = &c.Opts[i]
-				break
+		if len(name) == 1 {
+			optInfo = lookupOptionByShortName(c, name[0])
+		} else {
+			for i := range c.Opts {
+				if name == c.Opts[i].NameLong {
+					optInfo = &c.Opts[i]
+					break
+				}
 			}
 		}
 		if optInfo == nil {
@@ -508,7 +512,7 @@ func parse(c *CommandInfo, p *Command, args []string) error {
 				if c.Opts[i].NameLong != "" {
 					name = "--" + c.Opts[i].NameLong
 				} else {
-					name = "-" + c.Opts[i].NameShort
+					name = "-" + string(c.Opts[i].NameShort)
 				}
 				missing = append(missing, name)
 			}

help.go

@@ -31,8 +31,8 @@ func DefaultShortHelp(c *CommandInfo) string {
 	u.WriteString("\noptions:\n")
 	opts := slices.Clone(c.Opts)
 	slices.SortStableFunc(opts, func(a, b InputInfo) int {
-		nameToCmpA := a.NameShort
-		nameToCmpB := b.NameShort
+		nameToCmpA := string(a.NameShort)
+		nameToCmpB := string(b.NameShort)
 		if a.NameLong != "" {
 			nameToCmpA = a.NameLong
 		}
@@ -73,11 +73,11 @@ func DefaultShortHelp(c *CommandInfo) string {
 			}
 			var namesAndVal string
 			{
-				if o.NameShort != "" {
-					namesAndVal += "-" + o.NameShort
+				if o.NameShort != 0 {
+					namesAndVal += "-" + string(o.NameShort)
 				}
 				if o.NameLong != "" {
-					if o.NameShort != "" {
+					if o.NameShort != 0 {
 						namesAndVal += ", "
 					}
 					namesAndVal += "--" + o.NameLong
@@ -179,8 +179,8 @@ func DefaultFullHelp(c *CommandInfo) string {
 	u.WriteString("\noptions:\n")
 	opts := slices.Clone(c.Opts)
 	slices.SortStableFunc(opts, func(a, b InputInfo) int {
-		nameToCmpA := a.NameShort
-		nameToCmpB := b.NameShort
+		nameToCmpA := string(a.NameShort)
+		nameToCmpB := string(b.NameShort)
 		if a.NameLong != "" {
 			nameToCmpA = a.NameLong
 		}
@@ -200,11 +200,11 @@ func DefaultFullHelp(c *CommandInfo) string {
 
 		var usgNamesAndArg string
 		{
-			if o.NameShort != "" {
-				usgNamesAndArg += "-" + o.NameShort
+			if o.NameShort != 0 {
+				usgNamesAndArg += "-" + string(o.NameShort)
 			}
 			if o.NameLong != "" {
-				if o.NameShort != "" {
+				if o.NameShort != 0 {
 					usgNamesAndArg += ", "
 				}
 				usgNamesAndArg += "--" + o.NameLong
@@ -280,14 +280,14 @@ func DefaultFullHelp(c *CommandInfo) string {
 
 func (o *InputInfo) leftPaddedNames() string {
 	var s string
-	if o.NameShort != "" {
-		s += "-" + o.NameShort
+	if o.NameShort != 0 {
+		s += "-" + string(o.NameShort)
 	} else {
 		s += "   "
 	}
 
 	if o.NameLong != "" {
-		if o.NameShort != "" {
+		if o.NameShort != 0 {
 			s += ", "
 		} else {
 			s += " "