Generate BNF diagrams from an antlr grammar?

Question

I may well be asking something not achievable here.. Maybe someone can point out either

(a) What would be some steps (/tools?) to at least partially achieve creation of bnf diagrams from a (rather complex) antlr grammar

(b) why (if it were the case) this simply can not be achieved. E.g. maybe since antlr is extended BNF and its recursive structure differs from bnf requirements.. Along those lines.

Answer 1

ANTLRWorks 1 works for generating diagrams, one at a time, for rule.

for v4, ANTLRWorks 2 also generates them though I'm not sure it can save them to disk.

Ter

Answer 2

If it is an ANTLR 3 grammar, you could

• use http://bottlecaps.de/convert to convert it to W3C notation,
• with the result, proceed to http://bottlecaps.de/rr/ui for generating syntax diagrams.

Answer 3

Grako has an ANTLR3-to-EBNF translator in its examples. You can customize it to the BNF style you require (or to ANTLR4).