detect recursive rules

optimize 0*1x to [x]. already do this for 0*1(x).

word-wrap output.

intelligently word-wrap output. (is there such a thing?)

handle syntax error of missing rule, just leading "="

(initial attempts caused shift/reduce or reduce/reduce conflicts!)

canonify "a" / "A" (really "a"/foo/bar/baz/zip/dop/"A")

canonify "foo / foo"

Read in dependencies (including a built-in core.abnf?), don't check

their syntax and don't output them, just read in the rule names.

Parse inputs based on the grammar, say report whether or not they

match.

Play madlibs with the grammar, to see what else it might accept

why doesn't

foo = bar *

baz

fail?

check out indentation rules:

a = X

; this comment is indented wrong.

Y

and

a = X$

$

Y$

the WSP-only line is indented wrong.

return error if accepting ".." as range

Change error:

foo = bar

baz

to not just say that baz is not a valid new rule, but

also might be an indentation error. Do this only if

there was a def'n on the rpeviousline with no whitespace?