Replaces []Format with a Group type.
A bit more type safe.
Breaking change for RegisterFormat, now takes a first argument that is a "single" format group.
Lots of naming cleanup.
This is also preparation for decode group argument which will enable doing intresting
probing, ex a format decoder could know it's decode as part of probe group (html could
be probed possibly), or have "arg probe" group for decoder who inspect args to know
if they should probe (-d /path/to/schema etc) to enable nice CLI-ergonomics.
This will allow passing both cli options and format options to sub decoder.
Ex: pass keylog option to a tls decoder when decoding a pcap.
Ex: pass decode options to a format inside a http body inside a pcap.
Add ArgAs method to lookup argument based on type. This also makes the format
decode function have same signature as sub decoders in the decode API.
This change decode.Format a bit:
DecodeFn is now just func(d *D) any
DecodeInArg renamed to DefaultInArg
Feels less cluttered, easier to read and more consistent.
Still keep tovalue, tobytes etc that are more basic functions this
only renamed format related functions.
Also there is an exceptin for to/fromjson as it comes from jq.
Also fixes lots of spelling errors while reading thru.
Preparation to make decoder use less memory and API more type safe.
Now each scalar type has it's own struct type so it can store different
things and enables to have a scalar interface.
Also own types will enable experimenting with decode DLS designs like
using chained methods that are type aware.
json, yaml, toml, xml, html, csv are now normal formats and most of them also particiate
in probing (not html and csv).
Also fixes a bunch of bugs in to/fromxml, to/fromjq etc.
