How does params come into scope in Rails? -

How does params come into scope in Rails? -

in illustration code below new user created based on result of calling method user_params. method uses params. how params variable come scope? not prefixed @ symbol nor user_params take argument.

class userscontroller < applicationcontroller . . . def create @user = user.new(user_params) if @user.save # handle successful save. else render 'new' end end private def user_params params.require(:user).permit(:name, :email, :password, :password_confirmation) end end

the params instance method of class actioncontroller:: metal.

it extended by class actioncontroller::base.

ruby-on-rails