Recipient Command Exp Command Address Command HASH function

非終端記号(生成規則)定義 Recipient : = Command. Exp : = [Command] Address Command : = HASH function [PERIOD alias] HASH Address : = Add. Exp AT Domain : = Subdomain [PERIOD Domain. Arg]+ Add. Exp : = Mul. Exp [MINUS Mul. Exp | PLUS Mul. Exp] Mul. Exp : = Exp [PERIOD Exp] Exp : = rule OP_BRACE Paralist END_BRACE Paralist : = Para [PLUS Para] Para : = value [MINUS value]

文法(生成規則)定義 ( )* : 0回以上の繰り返し ( )+: 1回以上の繰り返し ( )? : 0回または 1回 Command. Exp() {　( Command() )? Address()　} Command() {　<HASH> Arg() (<PERIOD> Arg() )* <HASH>　} Address() {　Add. Exp() <AT> domain()　} domain() {　Arg() (<PERIOD> Arg() )+　} Add. Exp() {　Mul. Exp() ( <MINUS> Mul. Exp() |<PLUS> Mul. Exp() )*　} Mul. Exp() {　Exp() ( <PERIOD> Exp() )*　} Exp() {　Arg() <OP_BRACE> Paralist() <END_BRACE>　} Paralist() {　Para() ( <PLUS> Para() )*　} Para() {　Arg() ( <MINUS> Arg() )*　} Arg() {　<ARG>　}

dept{ics}. grade{3 -4}@keio. rmx. jp rule: dept grade Address (q 1) intersect (q 3) Mul. Exp q 1 rule [dept] Exp q 3 value [ics] keio. properties dept[1]=q 1 grade[1]=q 2 grade[2]=q 3 Domain q 3 rule sub d. Arg [keio] [rmx] d. Arg [jp] Paralist q 3 [grade] Para value [3] [4]