[RFC v2 0/4] flow_compile: textual flow rule compiler

[Bruce Richardson]

On Thu, May 07, 2026 at 09:09:23AM -0700, Stephen Hemminger wrote:
> On Thu, 7 May 2026 09:10:48 +0100
> Bruce Richardson <bruce.richardson at intel.com> wrote:
> 
> > > 1. API shape.  pcap_compile-style (one string -> opaque object ->
> > >    arrays) versus the three-call attr/pattern/actions form
> > >    Sismis's v12 exposes.  What does your application actually
> > >    want?
> > >   
> > 
> > For this, I wonder if we also could do with a second API for the creation
> > which takes a list of tokens rather than just a single string. Thinking
> > about integration with testpmd, or with apps which already have some
> > commandline interface which produces a list of tokens, having to re-stitch
> > the tokens together into one string seems awkward.
> > 
> > Also, have you already investigated how this might be integrated into
> > testpmd? Do we have the capability to pass multi-token strings via cmdline?
> 
> Lex pass does tokenizing in a way that is different than simple string split.
> Could have a wrapper that takes list of tokens and quotes them back to
> a string.
> 
> For testpmd integration.
>  - the new compiler may intentionally diverge from existing adhoc
>    parsing. The AI code generation already flagged a couple of these
>    and put note in documentation.
> 
>  - testpmd (and probably cmdline) will need ability to not pass unparsed
>    string, may need new cmdline type for "rest of line as string"
> 

Checking with Claude, it seems it's there already:

Multi-string (TOKEN_STRING_MULTI) — reads until cmdline_isendofcommand(), which stops only at \n, \r, \0, or #. This captures the entire remainder of the line including spaces.

>  - AI proposed new syntax:
>     flow compile <port> "quote rule"

I tend to prefer explicit pre-field names in the syntax as a general rule
as it makes it clearer what the numeric values in the command are. So I
suggest e.g.:

"flow_compile port <N> rule: ...."

In the absense of quoting, I think having a ":" at the end of rule helps to
separate the testpmd syntax from the rule syntax.

/Bruce