some treetop debug tips

Treetop seems pretty nice, but information on it’s usage is kind of scattered all over internet . Here are a few tips that I used to debug grammars:

1. You can try a specific rule by writing this:
   
tree = parser.parse(content,:root => "rule_name")

2. I usually have my code structured like this, to get some info about where the parser chokes:

   
   if tree
       puts "succesful"
   else
       puts "unsuccesful at #{parser.index}"
       puts parser.failure_reason
   end
   

Hope this helps you as much as it helped me.