[plt-scheme] drscheme and 'dabbrev-expand'

Hi,

It looks like DrScheme doesn't have a command for auto-completing words. 
  Is this true?  Is anyone working on this?  If not, I'll start digging 
into DrScheme extensions.  I want something like emacs's 
'dabbrev-expand', which is not semantically aware but is still very 
useful for saving typing and spelling mistakes on long identifiers.

Rob