Add option parsing

command.go

@@ -67,27 +67,34 @@ func (c *Command) Execute(args []string) {
 		args = args[1:]
 	}
 
-	if err := c.opts.Parse(args); err != nil {
+	restArgs, err := c.opts.Parse(args)
+	if err != nil {
 		c.ShowHelp()
 		return
 	}
 
-	if len(args) > 0 {
-		sc, ok := c.subcommands.Get(args[0])
-		if ok {
-			sc.Execute(args[1:])
-			return
-		}
+	restArgs, err = opts.Globals().Parse(restArgs)
+	if err != nil {
+		c.ShowHelp()
+		return
+	}
 
-		// TODO: remove when done with option parsing
-		if args[0] == "--help" {
-			c.ShowHelp()
+	if len(restArgs) > 0 {
+		sc, ok := c.subcommands.Get(restArgs[0])
+		if ok {
+			sc.Execute(restArgs[1:])
 			return
 		}
 	}
 
+	helpOpt, ok := opts.Globals().GetBool("help")
+	if ok && helpOpt.Value() {
+		c.ShowHelp()
+		return
+	}
+
 	if c.CanRun() {
-		c.Run(args)
+		c.Run(restArgs)
 		return
 	}
 

opts/bool.go

@@ -9,7 +9,7 @@ type BoolOption struct {
 	value       bool
 }
 
-var _ Option = (*StringOption)(nil)
+var _ Option = (*BoolOption)(nil)
 
 func Bool(name, shortName string, defaultValue bool, description string) *BoolOption {
 	return &BoolOption{
@@ -39,6 +39,7 @@ func (o *BoolOption) ShortName() string {
 // Value implements Option.
 func (o *BoolOption) Parse(raw string) error {
 	if raw == "" {
+		o.value = !o.value
 		return nil
 	}
 
@@ -51,6 +52,11 @@ func (o *BoolOption) Parse(raw string) error {
 	return nil
 }
 
+// TakesArg implements Option.
+func (*BoolOption) TakesArg() bool {
+	return false
+}
+
 func (o *BoolOption) Value() bool {
 	return o.value
 }

opts/float.go

@@ -51,6 +51,11 @@ func (o *FloatOption) Parse(raw string) error {
 	return nil
 }
 
+// TakesArg implements Option.
+func (*FloatOption) TakesArg() bool {
+	return true
+}
+
 func (o *FloatOption) Value() float64 {
 	return o.value
 }

opts/int.go

@@ -9,7 +9,7 @@ type IntOption struct {
 	value       int
 }
 
-var _ Option = (*StringOption)(nil)
+var _ Option = (*IntOption)(nil)
 
 func Int(name, shortName string, defaultValue int, description string) *IntOption {
 	return &IntOption{
@@ -51,6 +51,11 @@ func (o *IntOption) Parse(raw string) error {
 	return nil
 }
 
+// TakesArg implements Option.
+func (*IntOption) TakesArg() bool {
+	return true
+}
+
 func (o *IntOption) Value() int {
 	return o.value
 }

opts/option.go

@@ -7,6 +7,7 @@ type Option interface {
 	ShortName() string
 	Description() string
 	Parse(raw string) error
+	TakesArg() bool
 }
 
 func Names(o Option) string {

opts/parser.go

@@ -0,0 +1,143 @@
+package opts
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+var (
+	ErrInvalidShortOption = errors.New("invalid short option")
+	ErrCannotChainOption  = errors.New("cannot chain option as it takes an argument")
+)
+
+func (s Set) Parse(args []string) (restArgs []string, err error) {
+	for i := 0; i < len(args); i++ {
+		arg := args[i]
+
+		// Handle regular argument
+		if !strings.HasPrefix(arg, "-") {
+			restArgs = append(restArgs, arg)
+			continue
+		}
+
+		// Handle options terminator
+		if arg == "--" {
+			restArgs = append(restArgs, args[i+1:]...)
+			return
+		}
+
+		// Handle long option
+		if strings.HasPrefix(arg, "--") {
+			longName := arg[2:]
+			value := ""
+
+			equals := strings.Index(longName, "=")
+			if equals > 0 {
+				longName = longName[:equals]
+				value = longName[equals+1:]
+			} else if i < len(args)-1 && !strings.HasPrefix(args[i+1], "-") {
+				value = args[i+1]
+				i++
+			}
+
+			parsed := false
+			for _, opt := range s {
+				if opt.Name() != longName {
+					continue
+				}
+
+				if err = opt.Parse(value); err != nil {
+					return
+				}
+
+				parsed = true
+				break
+			}
+
+			if !parsed {
+				restArgs = append(restArgs, arg)
+			}
+
+			continue
+		}
+
+		// Handle short option
+		shortNames := arg[1:]
+		if len(shortNames) == 0 {
+			err = ErrInvalidShortOption
+		} else if len(shortNames) == 1 {
+			parsed := false
+			value := ""
+			if i < len(args)-1 && !strings.HasPrefix(args[i+1], "-") {
+				value = args[i+1]
+				i++
+			}
+
+			for _, opt := range s {
+				if opt.ShortName() != shortNames {
+					continue
+				}
+
+				if err = opt.Parse(value); err != nil {
+					return
+				}
+
+				parsed = true
+				break
+			}
+
+			if !parsed {
+				restArgs = append(restArgs, arg)
+			}
+		} else {
+			for j := 0; j < len(shortNames); j++ {
+				shortName := shortNames[j]
+				value := ""
+				takesValue := false
+				parsed := false
+
+				for _, opt := range s {
+					if opt.ShortName() != string(shortName) {
+						continue
+					}
+
+					if opt.TakesArg() {
+						if j > 0 {
+							err = ErrCannotChainOption
+							return
+						}
+
+						takesValue = true
+						value = shortNames[j+1:]
+						value = strings.TrimPrefix(value, "=")
+						if len(value) == 0 && i < len(args)-1 && !strings.HasPrefix(args[i+1], "-") {
+							value = args[i+1]
+							i++
+						}
+						j = len(shortNames)
+					}
+
+					parsed = true
+
+					if err = opt.Parse(value); err != nil {
+						return
+					}
+
+					break
+				}
+
+				if !parsed {
+					if takesValue {
+						restArgs = append(restArgs, arg)
+						break
+					} else {
+						restArgs = append(restArgs, fmt.Sprintf("-%c", shortName))
+					}
+				}
+			}
+		}
+	}
+
+	return
+}

opts/set.go

@@ -6,23 +6,6 @@ func NewSet() Set {
 	return Set{}
 }
 
-func (s *Set) Add(f Option) {
-	*s = append(*s, f)
-}
-
-func (s Set) Get(name string) (Option, bool) {
-	for _, f := range s {
-		if f.Name() == name {
-			return f, true
-		}
-
-		if f.ShortName() == name {
-			return f, true
-		}
-	}
-	return nil, false
-}
-
 func (s Set) MaxWidth() int {
 	max := 0
 	for _, f := range s {
@@ -33,7 +16,75 @@ func (s Set) MaxWidth() int {
 	return max
 }
 
-// TODO: Implement
-func (s Set) Parse(args []string) error {
-	return nil
+func (s *Set) Add(f Option) {
+	*s = append(*s, f)
+}
+
+func (s Set) Get(name string) (Option, bool) {
+	for _, o := range s {
+		if o.Name() == name {
+			return o, true
+		}
+
+		if o.ShortName() == name {
+			return o, true
+		}
+	}
+	return nil, false
+}
+
+func (s Set) GetBool(name string) (*BoolOption, bool) {
+	o, ok := s.Get(name)
+	if !ok {
+		return nil, false
+	}
+
+	b, ok := o.(*BoolOption)
+	if !ok {
+		return nil, false
+	}
+
+	return b, true
+}
+
+func (s Set) GetString(name string) (*StringOption, bool) {
+	o, ok := s.Get(name)
+	if !ok {
+		return nil, false
+	}
+
+	b, ok := o.(*StringOption)
+	if !ok {
+		return nil, false
+	}
+
+	return b, true
+}
+
+func (s Set) GetInt(name string) (*IntOption, bool) {
+	o, ok := s.Get(name)
+	if !ok {
+		return nil, false
+	}
+
+	b, ok := o.(*IntOption)
+	if !ok {
+		return nil, false
+	}
+
+	return b, true
+}
+
+func (s Set) GetFloat(name string) (*FloatOption, bool) {
+	o, ok := s.Get(name)
+	if !ok {
+		return nil, false
+	}
+
+	b, ok := o.(*FloatOption)
+	if !ok {
+		return nil, false
+	}
+
+	return b, true
 }

opts/string.go

@@ -43,6 +43,11 @@ func (o *StringOption) Parse(raw string) error {
 	return nil
 }
 
+// TakesArg implements Option.
+func (*StringOption) TakesArg() bool {
+	return true
+}
+
 func (o *StringOption) Value() string {
 	return o.value
 }