New syntax to include or add spice into bot scripts (directive)

[vunb]

New syntax in BotScript document: Directive

• Directive is an instruction that helps Engine understand enhanced implementation

# include bot scripts from url (support get method only)
/include: text or [definition]
- url 1
- url 2

# use your custom nlu server
/nlu: text or [definition]
- server 1
- server 2