Parse-tree driven diff

[Jonathan P. Leech]

    Does  anyone  out  there  know  of	a  'diff'-like	program  which
compares the parse trees of C source code? I am faced  with  the  task
of merging two copies of a fairly large (~30000) lines	program  which
have diverged significantly over several years,  to  the  point  where
diff will spew out almost the  entire  files  -  yet  the  same  basic
structure is still there.
    In the (unlikely) event of positive responses, I'll  summarize  to
the net.
	Thanks,
	Jon Leech (jon at csvax.caltech.edu || seismo!cit-vax!jon)
	__@/