kapil___, in more recent Ruby there is Hash#dig, but you'll still have to worry about type-safety. Why don't you know your the kind of data anyway?
I'm working with vim, have done so for the past 20 years, but I don't know what you're talking about :-)
Looks like #send syntax. Based on language, my guess is that it's a dangerous monkey patch to Object. I'd imagine it checks presence of given method, and #sends given arguments if present, or return nil or something similar if not.
I haven't bothered to check ruby lexer, but practical experience says you can't have whitespace between a method name and its parameters /if/ you're using parenthesis when calling a method. "rrr(3,4)" and "rrr 3, 4" are fine, "rrr (3, 4)" is not.