4 EBNF 句法
- 用小写标识符代表语法结构，用大写标识符代表结构词类即终结符
- 用并置表示连接，用
|表示选择，用&同时表示二者（如A & B等价于A | B | A B） - 用
[]表示可选（\(0\) 或 \(1\) 次），用+表示重复（\(1\) 或多次），用A *表示[A +]（\(0\) 或多次） -
用
()改变优先级（+ > & > |），用//表示可省略终止符text := [NAI +] [CMENE + * | (indicators & free +)] [joik-jek] text-1 text-1 := [(I [jek | joik] [[stag] BO] *) + | NIhO + *] [paragraphs] paragraphs := paragraph [NIhO + * paragraphs] paragraph := (statement | fragment) [I * [statement | fragment]] + statement := statement-1 | prenex statement statement-1 := statement-2 [I joik-jek [statement-2]] + statement-2 := statement-3 [I [jek | joik] [stag] BO * [statement-2]] statement-3 := sentence | [tag] TUhE * text-1 /TUhU*/ fragment := ek * | gihek * | quantifier | NA * | terms /VAU*/ | prenex | relative-clauses | links | linkargs prenex := terms ZOhU * sentence := [terms [CU *]] bridi-tail subsentence := sentence | prenex subsentence bridi-tail := bridi-tail-1 [gihek [stag] KE * bridi-tail /KEhE*/ tail-terms] bridi-tail-1 := bridi-tail-2 [gihek * bridi-tail-2 tail-terms] + bridi-tail-2 := bridi-tail-3 [gihek [stag] BO * bridi-tail-2 tail-terms] bridi-tail-3 := selbri tail-terms | gek-sentence gek-sentence := gek subsentence gik subsentence tail-terms | [tag] KE * gek-sentence /KEhE*/ | NA * gek-sentence tail-terms := [terms] /VAU*/ terms := terms-1 + terms-1 := terms-2 [PEhE * joik-jek terms-2] + terms-2 := term [CEhE * term] + term := sumti | (tag | FA *) (sumti | /KU*/) | termset | NA KU * termset := NUhI * gek terms /NUhU*/ gik terms /NUhU*/ | NUhI * terms /NUhU*/ sumti := sumti-1 [VUhO * relative-clauses] sumti-1 := sumti-2 [(ek | joik) [stag] KE * sumti /KEhE*/] sumti-2 := sumti-3 [joik-ek sumti-3] + sumti-3 := sumti-4 [(ek | joik) [stag] BO * sumti-3] sumti-4 := sumti-5 | gek sumti gik sumti-4 sumti-5 := [quantifier] sumti-6 [relative-clauses] | quantifier selbri /KU*/ [relative-clauses] sumti-6 := (LAhE * | NAhE BO *) [relative-clauses] sumti /LUhU*/ | KOhA * | lerfu-string /BOI*/ | LA * [relative-clauses] CMENE + * | (LA | LE) * sumti-tail /KU*/ | LI * mex /LOhO*/ | ZO any-word * | LU text /LIhU*/ | LOhU any-word + LEhU * | ZOI any-word anything any-word * sumti-tail := [sumti-6 [relative-clauses]] sumti-tail-1 | relative-clauses sumti-tail-1 sumti-tail-1 := [quantifier] selbri [relative-clauses] | quantifier sumti relative-clauses := relative-clause [ZIhE * relative-clause] + relative-clause := GOI * term /GEhU*/ | NOI * subsentence /KUhO*/ selbri := [tag] selbri-1 selbri-1 := selbri-2 | NA * selbri selbri-2 := selbri-3 [CO * selbri-2] selbri-3 := selbri-4 + selbri-4 := selbri-5 [joik-jek selbri-5 | joik [stag] KE * selbri-3 /KEhE*/] + selbri-5 := selbri-6 [(jek | joik) [stag] BO * selbri-5] selbri-6 := tanru-unit [BO * selbri-6] | [NAhE *] guhek selbri gik selbri-6 tanru-unit := tanru-unit-1 [CEI * tanru-unit-1] + tanru-unit-1 := tanru-unit-2 [linkargs] tanru-unit-2 := BRIVLA * | GOhA [RAhO] * | KE * selbri-3 /KEhE*/ | ME * sumti /MEhU*/ [MOI *] | (number | lerfu-string) MOI * | NUhA * mex-operator | SE * tanru-unit-2 | JAI * [tag] tanru-unit-2 | any-word (ZEI any-word) + | NAhE * tanru-unit-2 | NU [NAI] * [joik-jek NU [NAI] *] + subsentence /KEI*/ linkargs := BE * term [links] /BEhO*/ links := BEI * term [links] quantifier := number /BOI*/ | VEI * mex /VEhO*/ mex := mex-1 [operator mex-1] + | FUhA * rp-expression mex-1 := mex-2 [BIhE * operator mex-1] mex-2 := operand | [PEhO *] operator mex-2 + /KUhE*/ rp-expression := rp-operand rp-operand operator rp-operand := operand | rp-expression operator := operator-1 [joik-jek operator-1 | joik [stag] KE * operator /KEhE*/] + operator-1 := operator-2 | guhek operator-1 gik operator-2 | operator-2 (jek | joik) [stag] BO * operator-1 operator-2 := mex-operator | KE * operator /KEhE*/ mex-operator := SE * mex-operator | NAhE * mex-operator | MAhO * mex /TEhU*/ | NAhU * selbri /TEhU*/ | VUhU * operand := operand-1 [(ek | joik) [stag] KE * operand /KEhE*/] operand-1 := operand-2 [joik-ek operand-2] + operand-2 := operand-3 [(ek | joik) [stag] BO * operand-2] operand-3 := quantifier | lerfu-string /BOI*/ | NIhE * selbri /TEhU*/ | MOhE * sumti /TEhU*/ | JOhI * mex-2 + /TEhU*/ | gek operand gik operand-3 | (LAhE * | NAhE BO *) operand /LUhU*/ number := PA [PA | lerfu-word] + lerfu-string := lerfu-word [PA | lerfu-word] + lerfu-word := BY | any-word BU | LAU lerfu-word | TEI lerfu-string FOI ek := [NA] [SE] A [NAI] gihek := [NA] [SE] GIhA [NAI] jek := [NA] [SE] JA [NAI] joik := [SE] JOI [NAI] | interval | GAhO interval GAhO interval := [SE] BIhI [NAI] joik-ek := joik * | ek * joik-jek := joik * | jek * gek := [SE] GA [NAI] * | joik GI * | stag gik guhek := [SE] GUhA [NAI] * gik := GI [NAI] * tag := tense-modal [joik-jek tense-modal] + stag := simple-tense-modal [(jek | joik) simple-tense-modal] + tense-modal := simple-tense-modal * | FIhO * selbri /FEhU*/ simple-tense-modal := [NAhE] [SE] BAI [NAI] [KI] | [NAhE] (time [space] | space [time]) & CAhA [KI] | KI | CUhE time := ZI & time-offset + & ZEhA [PU [NAI]] & interval-property + time-offset := PU [NAI] [ZI] space := VA & space-offset + & space-interval & (MOhI space-offset) space-offset := FAhA [NAI] [VA] space-interval := ((VEhA & VIhA) [FAhA [NAI]]) & space-int-props space-int-props := (FEhE interval-property) + interval-property := number ROI [NAI] | TAhE [NAI] | ZAhO [NAI] free := SEI * [terms [CU *]] selbri /SEhU/ | SOI * sumti [sumti] /SEhU/ | vocative [relative-clauses] selbri [relative-clauses] /DOhU/ | vocative [relative-clauses] CMENE + * [relative-clauses] /DOhU/ | vocative [sumti] /DOhU/ | (number | lerfu-string) MAI | TO text /TOI/ | XI * (number | lerfu-string) /BOI/ | XI * VEI * mex /VEhO/ vocative := (COI [NAI]) + & DOI indicators := [FUhE] indicator + indicator := (UI | CAI) [NAI] | Y | DAhO | FUhO word := [BAhE] any-word [indicators] any-word := "any single word (no compound cmavo)" anything := "any text at all, whether Lojban or not" null := any-word SI | utterance SA | text SU