[R] trying to mimic page 70 of Software for Data Analysis

[markleeds at verizon.net]

I was trying to do what is on page 70 of John Chambers' new book namely 
using trace to invoke the browser by doing

trace(zapsmall, edit = TRUE)

but , typing above at an R prompt, I get

  trace(zapsmall, edit=TRUE)
sh: EMACS: command not found
Error in edit(name, file, title, editor) :
   problem with running editor EMACS

I looked in the archives but maybe it's a problem with the keywords I 
was using. If anyone could tell me what I need to do, it would be great. 
I'm thinking that I need to put something in my .Rprofile but I'm not 
sure what.  Thanks.

Oh, I use linux and my sessionInfo is below and I am using  GNU Emacs 
22.1.1. I usually use ESS and EMACS together but for this I figured it 
would be simpler to start from the R-prompt so that I was aligned with 
John's book as much as possible.

 
#============================================================================

sessionInfo()
R version 2.7.0 (2008-04-22)
i686-redhat-linux-gnu

locale:
 
LC_CTYPE=en_US.UTF-8;LC_NUMERIC=C;LC_TIME=en_US.UTF-8;LC_COLLATE=en_US.UTF-8;LC_MONETARY=C;LC_MESSAGES=en_US.UTF-8;LC_PAPER=en_US.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_IDENTIFICATION=C

attached base packages:
[1] datasets  utils     stats     graphics  grDevices methods   base

other attached packages:
  [1] gsubfn_0.3-3       proto_0.3-8        latticeExtra_0.4-1 
RColorBrewer_1.0-2 lattice_0.17-7     faraway_1.0.3      nnet_7.2-42 
car_1.2-8          reshape_0.8.0
[10] zoo_1.5-3          chron_2.3-22       MASS_7.2-42

loaded via a namespace (and not attached):
[1] grid_2.7.0