Omron PLC与Kepware OPC通信Omron PLC与Kepware OPC通信Omron PLC与Kepware OPC通信

三地址代码是编译原理语法分析后的中间语言的一种，这是我刚完成的三地址代码生成器，符合的语法规则及其语义规则如下（S→if C then S1 else S2，这条规则没有加，其余都已完成，也许还有bug，欢迎大家给予指正）：产生式 语义规则S → id = E S.code = E.code || gen(id.place’:=’E.place)S → if C then S1 C.true = newlabel; C.false = S.next;S1.next = S.next;S.code = C.code || gen(E.true’:’) || S1.codeS → if C then S1 else S2 C.true = newlabel; C.false = newlabel;S1.next = S2.next =S.next;S.code = C.code || gen(E.true’:’) || S1.code ||gen(‘goto’,S.next)|| gen(E.false’:’) || S2.codeS → while C do S1 S.begin = newlabel; C.true = newlabel;C.false = S.next; S1.next = S.begin;S.code = gen(S.begin’:’) || C.code ||gen(E.true’:’) || S1.code || gen(‘goto’S.begin);C → E1 > E2 C.code = E1.code || E2.code ||gen(‘if’E1.place’>’E2.place’goto’C.true) ||gen(‘goto’C.false)C → E1 < E2 C.code = E1.code || E2.code ||gen(‘if’E1.place’<’E2.place’goto’C.true) ||gen(‘goto’C.false)C → E1 = E2 C.code = E1.code || E2.code ||gen(‘if’E1.place’=’E2.place’goto’C.true) ||gen(‘goto’C.false)E → E1 + T E.place = newtemp;E.code = E1.code||T.code||gen(E.place’:=’E1.place’+’T.place)E → E1 - T E.place = newtemp; E.code = E1.code || T.code ||gen(E.place’:=’E1.place’-’T.place)E → T E.place = T.place; E.code = T.codeT → F T.place = F.place; T.code = F.codeT → T1 * F T.place = newtemp;T.code = T1.code || F.code ||gen(T.place’:=’T1.place’*’F.place)T → T1 / F T.place = newtemp; T.code = T1.code || F.code ||gen(T.place’:=’T1.place’/’F.place)F → ( E ) F.place = E