discord: Improve union interface documentation; fix *Option JSON

discord/command.go

@@ -255,6 +255,20 @@ const (
 
 // CommandOption is a union of command option types. The constructors for
 // CommandOption will hint the types that can be a CommandOption.
+//
+// The following types implement this interface:
+//
+//    - *SubcommandGroupOption
+//    - *SubcommandOption
+//    - *StringOption
+//    - *IntegerOption
+//    - *BooleanOption
+//    - *UserOption
+//    - *ChannelOption
+//    - *RoleOption
+//    - *MentionableOption
+//    - *NumberOption
+//
 type CommandOption interface {
 	Name() string
 	Type() CommandOptionType
@@ -329,6 +343,18 @@ func (s *SubcommandOption) UnmarshalJSON(b []byte) error {
 }
 
 // CommandOptionValue is a subcommand option that fits into a subcommand.
+//
+// The following types implement this interface:
+//
+//    - *StringOption
+//    - *IntegerOption
+//    - *BooleanOption
+//    - *UserOption
+//    - *ChannelOption
+//    - *RoleOption
+//    - *MentionableOption
+//    - *NumberOption
+//
 type CommandOptionValue interface {
 	CommandOption
 	_val()
@@ -641,3 +667,39 @@ func (u *UserOption) MarshalJSON() ([]byte, error) {
 		raw:  (*raw)(u),
 	})
 }
+
+// MarshalJSON marshals ChannelOption to JSON with the "type" field.
+func (c *ChannelOption) MarshalJSON() ([]byte, error) {
+	type raw ChannelOption
+	return json.Marshal(struct {
+		Type CommandOptionType `json:"type"`
+		*raw
+	}{
+		Type: c.Type(),
+		raw:  (*raw)(c),
+	})
+}
+
+// MarshalJSON marshals RoleOption to JSON with the "type" field.
+func (r *RoleOption) MarshalJSON() ([]byte, error) {
+	type raw RoleOption
+	return json.Marshal(struct {
+		Type CommandOptionType `json:"type"`
+		*raw
+	}{
+		Type: r.Type(),
+		raw:  (*raw)(r),
+	})
+}
+
+// MarshalJSON marshals MentionableOption to JSON with the "type" field.
+func (m *MentionableOption) MarshalJSON() ([]byte, error) {
+	type raw MentionableOption
+	return json.Marshal(struct {
+		Type CommandOptionType `json:"type"`
+		*raw
+	}{
+		Type: m.Type(),
+		raw:  (*raw)(m),
+	})
+}

discord/component.go

@@ -64,6 +64,13 @@ func (c *ContainerComponents) UnmarshalJSON(b []byte) error {
 // Component is a component that can be attached to an interaction response. A
 // Component is either an InteractiveComponent or a ContainerComponent. See
 // those appropriate types for more information.
+//
+// The following types satisfy this interface:
+//
+//    - *ActionRowComponent
+//    - *ButtonComponent
+//    - *SelectComponent
+//
 type Component interface {
 	// Type returns the type of the underlying component.
 	Type() ComponentType
@@ -73,6 +80,12 @@ type Component interface {
 // InteractiveComponent extends the Component for components that are
 // interactible, or components that aren't containers (like ActionRow). This is
 // useful for ActionRow to type-check that no nested ActionRows are allowed.
+//
+// The following types satisfy this interface:
+//
+//    - *ButtonComponent
+//    - *SelectComponent
+//
 type InteractiveComponent interface {
 	Component
 	// ID returns the ID of the underlying component.
@@ -83,6 +96,11 @@ type InteractiveComponent interface {
 // ContainerComponent is the opposite of InteractiveComponent: it describes
 // components that only contain other components. The only component that
 // satisfies that is ActionRow.
+//
+// The following types satisfy this interface:
+//
+//    - *ActionRowComponent
+//
 type ContainerComponent interface {
 	Component
 	_ctn()

discord/interaction.go

@@ -132,8 +132,16 @@ const (
 
 // InteractionData holds the respose data of an interaction, or more
 // specifically, the data that Discord sends to us. Type assertions should be
-// made on it to access the underlying data. The underlying types of the
-// Responses are value types. See the constructors for the possible types.
+// made on it to access the underlying data.
+//
+// The following types implement this interface:
+//
+//    - *PingInteraction
+//    - *AutocompleteInteraction
+//    - *CommandInteraction
+//    - *SelectInteraction (also ComponentInteraction)
+//    - *ButtonInteraction (also ComponentInteraction)
+//
 type InteractionData interface {
 	InteractionType() InteractionDataType
 	data()
@@ -173,8 +181,13 @@ func (*AutocompleteInteraction) InteractionType() InteractionDataType {
 func (*AutocompleteInteraction) data() {}
 
 // ComponentInteraction is a union component interaction response types. The
-// types can be whatever the constructors for this type will return. Underlying
-// types of Response are all value types.
+// types can be whatever the constructors for this type will return.
+//
+// The following types implement this interface:
+//
+//    - *SelectInteraction
+//    - *ButtonInteraction
+//
 type ComponentInteraction interface {
 	InteractionData
 	// ID returns the ID of the component in response. Not all component

utils/generate-option-marshalers.sh

@@ -12,29 +12,19 @@ types=(
 	MentionableOption
 )
 
-recvs=(
-	s
-	s
-	s
-	i
-	b
-	u
-	c
-	r
-	m
-)
+for ((i = 0; i < ${#types[@]}; i++)); {
+	recv=$(head -c1 <<< "${types[$i]}" | tr "[:upper:]" "[:lower:]")
 
-for ((i = 0; i < 6; i++)); {
 	cat<<EOF
 // MarshalJSON marshals ${types[$i]} to JSON with the "type" field.
-func (${recvs[$i]} *${types[$i]}) MarshalJSON() ([]byte, error) {
+func (${recv} *${types[$i]}) MarshalJSON() ([]byte, error) {
 	type raw ${types[$i]}
 	return json.Marshal(struct {
 		Type CommandOptionType \`json:"type"\`
 		*raw
 	}{
-		Type: ${recvs[$i]}.Type(),
-		raw:  (*raw)(${recvs[$i]}),
+		Type: ${recv}.Type(),
+		raw:  (*raw)(${recv}),
 	})
 }