[bug#61527] [PATCH] Add edgelist graph backend

[Simon Tournier]

Hi Kyle,

Thank you for your inputs on the topic. :-)


On lun., 27 févr. 2023 at 23:48, Ludovic Courtès <ludo@gnu.org> wrote:

> Is “CSV edge list” some sort of a standard format, or is it more of an
> idea you came up with?

In addition to Ludo’s suggestions below, and commenting your answer [1],
instead of “edgelist” backend – which seems well documented by igraph so
it could be confusing for igraph folk, if any :-) – instead of
“edgelist” backend I would use “csv”.  WDYT?

Quoting [1] for context:

> > Here, I would add the description of the data as header of the CSV-like
> > file.  For instance, something:
> >
> > --8<---------------cut here---------------start------------->8---
> > # type, name-or-edge1, item-or-edge2
> > # package, name, item
> > # depends, edge1, edge2
> > --8<---------------cut here---------------end--------------->8---
>
> I toyed with calling columns 2 and 3 "parent/child", "source/sink",
> "input/output", "origin/destination". The "input/output" option sounds
> the best to me.

This “input/output” does not sound to me.  I would keep something like:

--8<---------------cut here---------------start------------->8---
# type, name-or-from, vertex-or-to
# package, name, vertex
# depends, from, to
--8<---------------cut here---------------end--------------->8---

Thinking a bit about this format, I agree with you that this “format”
covers various needs feeding Python, R, etc. graph libraries.  And it is
easy to filter via plain pipe “| grep depends“ or else.


1: <878rgynpox.fsf@posteo.net">https://issues.guix.gnu.org/msgid/878rgynpox.fsf@posteo.net>


> The patch LGTM but we’ll need a couple more things:
>
>   1. Maybe emitting extra metadata as Simon suggested.
>
>   2. Adding documentation under “Invoking guix graph”.  In particular,
>      it’d be nice to have an example showing how to query the generated
>      CSV with igraph.
>
>   3. Ideally a full patch with commit log as generated with ‘git
>      format-patch’.  :-)
>
> Could you send an updated patch?

Let me know if you need help. :-)

Cheers,
simon