function [match,idx] = match_production(top,rule)idx = 1;match = 0;while (idx+length(rule)-1 <= length(top)) && ~(match)  match = 1;  for k = 1:length(rule)    if ~strcmp(top{idx+k-1}.symbol,rule{k})      match = 0;      break;    end  end  if ~match    idx = idx + 1;  endend% -----------------------------------------------------------------------------