sentence: see also extended backus–naur form augmented backus–naur form translational backus-naur form syntax diagram ( railroad diagram ) definite clause grammar , a more expressive alternative to bnf used in prolog wirth syntax notation , an alternative to bnf from 1977 pseudocode , a similar concept metalanguage software using bnf antlr , another parser generator written in java bnf converter ( bnfc ) coco/r , compiler generator accepting an attributed grammar in ebnf dms software reengineering toolkit , program analysis and transformation system for arbitrary languages gold bnf parser gnu bison , gnu version of yacc rpa bnf parser .