# File lib/squish.rb, line 435
def extractAllVars
  ## todo: reset state first? same issue re xmlns / USING...
  clauses.each { |qt|
    parts = qt[0..3]
    parts.each { |term|
     if term =~ /^\?(.*)/
       l = self.all_vars[$1] # look for list of clauses using this variable
       if l == nil
         self.all_vars[$1] = [qt]
       else
        self.all_vars[$1].push(qt)
       end
     end
    }
  }
end