function node = visit(node)global AP_NAME AP_BUILD_INFO% traverse the tree to find atomic propositionsif strcmp(node.symbol,'ap')  switch node.production    case 'polyap',      apname = node.value{1}.value;      if ~ismember(apname,AP_NAME)        new = length(AP_NAME)+1;        AP_NAME{new} = apname;        AP_BUILD_INFO{new} = {'polyap'};      end      % replace subtree by a single leaf node representing apname      node.production = 'none';      node.value = apname;    case 'fsmap',      fsmname = node.value{1}.value;      statename = node.value{3}.value;      apname = [fsmname '_in_' statename];      if ~ismember(apname,AP_NAME)        new = length(AP_NAME)+1;        AP_NAME{new} = apname;        AP_BUILD_INFO{new} = {'fsmap' fsmname statename};      end      % replace subtree by a single leaf node representing this finite      % state machine atomic proposition      node.production = 'none';      node.value = apname;    otherwise,      error(['Unknown production ''' node.production              ''' for atomic proposition'])% moved  endelse  if ~ischar(node.value)    for k = 1:length(node.value)      node.value{k} = visit(node.value{k});    end  endend