How can I autocomplete $ after typing PHP variables


As the screenshot shown, when I type token, suggestion tokenExpried appears with a letter “v” in front of it. But the autocomplete will only complete the whole word without sign in PHP. What I want is to type some part of variable -> given some suggestions -> select a suggestion -> autocomplete variable with prepend. Is it possible with some plugin now? Or If I want to implement this feature, where should I begin?

Thank you.