A tiny DSL in C to parse and validate complicated options
such as the device (,) stream (:) specifiers in ffmpeg.
Parse arg according to .spec and the vc validators at vv.
Return 1 if all the validators wrote their outs.
Otherwise complain as av0 and return 0.
(spec+1) is a string of fields in arg divided by *spec.
Example: The following code parses arg on '-'s into f, n, and u,
describing them as "filename", "count", and "uuid" in
error messages from "wtf" whenever there's a problem.
char f[PATH_MAX]; long n; uuid_t u;
const wtf_valid_t vs[] = {
{ &wtf_filename, f }, { &wtf_slongint, &n }, { &wtf_someuuid, u }
};
const wtf_validator_t validator = {
.av0 = "wtf", .vc = sizeof vs / sizeof vs[0], .vv = vs,
.spec = "-" "filename-count-uuid"
};
assert(wtf_validate(&validator, arg));
You may need a uuid_t type. See wtf_someuuid() in wtf.c.