PARSER_BEGIN(prefix2)

public class prefix2 {
}


PARSER_END(prefix2)
SKIP : 
{
        " "
|       "\n"
}

TOKEN : 
{
        < PLUS: "+">
|       < MINUS: "-">
|       < TIMES: "*">
|       < DIVIDE: "/">
|       < INTEGER_LITERAL: (["0"-"9"])+ >
}

void program():
{}
{    expression() <EOF>
}

void expression():
{}
{
       (<PLUS> | <MINUS> | <TIMES> | <DIVIDE>) expression() expression()
|       <INTEGER_LITERAL>
}