BlockVariableMap &else_variables = variables.back();
for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
{
BlockVariableMap::iterator j = if_variables.find(i->first);
if(j!=if_variables.end())
{
BlockVariableMap &else_variables = variables.back();
for(BlockVariableMap::iterator i=else_variables.begin(); i!=else_variables.end(); ++i)
{
BlockVariableMap::iterator j = if_variables.find(i->first);
if(j!=if_variables.end())
{