tidoust
commented
3 years ago I'm closing this issue as the spec now integrates railroad diagrams. The update process is slightly convoluted (ABNF => EBNF => XHTML => HTML) but in practice one only needs to run npm run update-grammar.
The ABNF grammar format is hard to understand, so it would make sense to include the much easier railroad diagrams for productions. The following were produced using Gunther Rademacher's https://bottlecaps.de/rr/ui online generator with the following grammar:
chunksDoc ::= ws (statement (sep statement) ws)? sep ::= ws (";" | #xA) ws / xA is linefeed or \n */ statement ::= link | rule | chunk link ::= name ws+ name ws+ name rule ::= chunklist ws "=>" ws chunklist chunklist ::= chunk ( ws ',' ws chunk ) chunk ::= type ws+ ID? ws "{" property "}" type ::= name ID ::= name property ::= ws name ws+ valuelist sep valuelist ::= value (ws "," ws valuelist) value ::= boolean | number | name | ISO8601 | string name ::= '@'? [a-zA-Z.-_:/]+ digit boolean ::= "true" | "false" number ::= integer | decimal | double integer ::= [+-]? digit+ decimal ::= [+-]? digit+ '.' digit+ double ::= [+-]? (digit+ '.' digit exp | '.' digit+ exp | digit+ exp) exp ::= [eE] [+-]? digit+ string ::= '"' ([^#x22#x5C#xA#xD] | ECHAR | UCHAR) '"' /* string literals exclude #x22=" #x5C=\ #xA=new line #xD=carriage return / ws ::= #x20 | #x9 | #xD | #xA /* #x20=space #x9=character tabulation #xD=carriage return #xA=new line / ISO8601 ::= year ("-" month ("-" day ("T" hour ":" minute second? timezone?)?)?)? /* a commonly used subset of the full ISO 8601 standard */ year ::= digit digit digit digit month ::= digit digit day ::= digit digit hour ::= digit digit minute ::= digit digit second ::= ":" digit digit ("." digit+)? timeszone ::= "Z" | ([+-] h h (":" m m)?) h ::= digit m ::= digit digit ::= [0-9]
See PNG diagrams in chunk-grammar.zip n.b. Github wouldn't accept the XHTML file with embedded SVG, and doesn't appear to accept SVG either, sigh.