It has the look of a production grammar with the reduction actions stripped out (but whatever they used didn't strip the %{ initializer block).  I would say that, for starters, you want to strip or modify the %{ block, and possibly remove/replace the empty { } actions in the grammar.  More I can't say; I know yacc, not happy.

-- 

brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com

system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu

electrical and computer engineering, carnegie mellon university    KF8NH