is it possible to high a block of code?

[Stephen Eglen]

 > as well as the other suggestions (narrowing, and outline mode),
 > emacswiki.org has the following, which seems to hide a currently
 > defined region.  If you want to mark up hideable regions using regexps
 > in your text, I doubt this will work, but the author of this package
 > might be able to point you in the right direction.
 > 
 > http://www.emacswiki.org/cgi-bin/wiki/HideRegion

p.s. the Emacswiki also reminded me about hide-ifdef-mode which comes
with Emacs; it was designed for hiding #ifdef ... #endif regions in C
code.  That might be adaptable to your case.

stephen