[plt-scheme] Word completion

Hi all,

Today (prompted by a student's penchant for impenetrably terse  
identifier names) I spent some time looking at the word completion  
feature in DrScheme.  AFAICT the only words that can be auto-completed  
(at least via C-/) are those drawn from the docs.  Is that correct?

In searching I found some (fairly old) posts suggesting that  
completion wasn't offered for names in the program text, because  
recognizing defined names would be complicated by the presence of  
macros.  Is that still the case?

If so, it would be Really Neat to have something like the completion I  
know & love from vim (yes, I'm a wacky vi-using schemer), where you  
can type the first few letters of a word, then use C-p and C-n to  
cycle through completions drawn from the nearest identically-prefixed  
words before and after (respectively) the insertion point.  Usually  
the names I want to complete are nearby anyway, so it works well.   
Does this functionality (or similar) exist?

Best,
Jordan