Bot API improvements

bot/ctx.go

@@ -143,6 +143,17 @@ func New(s *state.State, cmd interface{}) (*Context, error) {
 	return ctx, nil
 }
 
+func (ctx *Context) MustRegisterSubcommand(cmd interface{}) *Subcommand {
+	s, err := ctx.RegisterSubcommand(cmd)
+	if err != nil {
+		panic(err)
+	}
+
+	return s
+}
+
+// RegisterSubcommand registers and adds cmd to the list of subcommands. It will
+// also return the resulting Subcommand.
 func (ctx *Context) RegisterSubcommand(cmd interface{}) (*Subcommand, error) {
 	s, err := NewSubcommand(cmd)
 	if err != nil {

bot/extras/arguments/mention.go

@@ -3,6 +3,8 @@ package arguments
 import (
 	"errors"
 	"regexp"
+
+	"github.com/diamondburned/arikawa/discord"
 )
 
 var (
@@ -11,42 +13,52 @@ var (
 	RoleRegex    = regexp.MustCompile(`<@&(\d+)>`)
 )
 
-type ChannelMention string
+type ChannelMention discord.Snowflake
 
 func (m *ChannelMention) Parse(arg string) error {
-	return grabFirst(ChannelRegex, "channel mention", arg, (*string)(m))
+	return grabFirst(ChannelRegex, "channel mention",
+		arg, (*discord.Snowflake)(m))
 }
 
 func (m *ChannelMention) Usage() string {
 	return "#channel"
 }
 
-type UserMention string
+type UserMention discord.Snowflake
 
 func (m *UserMention) Parse(arg string) error {
-	return grabFirst(UserRegex, "user mention", arg, (*string)(m))
+	return grabFirst(UserRegex, "user mention",
+		arg, (*discord.Snowflake)(m))
 }
 
 func (m *UserMention) Usage() string {
 	return "@user"
 }
 
-type RoleMention string
+type RoleMention discord.Snowflake
 
 func (m *RoleMention) Parse(arg string) error {
-	return grabFirst(RoleRegex, "role mention", arg, (*string)(m))
+	return grabFirst(RoleRegex, "role mention",
+		arg, (*discord.Snowflake)(m))
 }
 
 func (m *RoleMention) Usage() string {
 	return "@role"
 }
 
-func grabFirst(reg *regexp.Regexp, item, input string, output *string) error {
+func grabFirst(reg *regexp.Regexp,
+	item, input string, output *discord.Snowflake) error {
+
 	matches := reg.FindStringSubmatch(input)
 	if len(matches) < 2 {
 		return errors.New("Invalid " + item)
 	}
 
-	*output = matches[1]
+	id, err := discord.ParseSnowflake(matches[1])
+	if err != nil {
+		return errors.New("Invalid " + item)
+	}
+
+	*output = id
 	return nil
 }

discord/snowflake.go

@@ -14,6 +14,15 @@ func NewSnowflake(t time.Time) Snowflake {
 	return Snowflake(TimeToDiscordEpoch(t) << 22)
 }
 
+func ParseSnowflake(sf string) (Snowflake, error) {
+	i, err := strconv.ParseInt(sf, 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	return Snowflake(i), nil
+}
+
 func (s *Snowflake) UnmarshalJSON(v []byte) error {
 	id := strings.Trim(string(v), `"`)
 	if id == "null" {