[bug#27907] [PATCH] graph: Provide access to the package record in the emit

[Roel Janssen]

Ludovic Courtès writes:

> Roel Janssen <address@hidden> skribis:
>
>> Oops!  I am sorry about this.  Would it not break if we include a check for 
>> whether
>> the node type is a package or not.  Then, non-package node types are
>> handled the “old way” and packages are handled the “new way”.
>>
>> I think we cannot have a generic way of exposing the specifics of a node
>> type, so if we need to expose more information for the other node types,
>> we have to add a type-specific implementation.
>
> Actually, we might need to discuss the specifics of why you wanted to do
> it in the first place.  :-)
>
> It is to pass extra rendering info to the backends?  (It would be
> helpful for instance to adjust the node color or size depending on
> certain parameters such as its size or number of dependents.)

Not necessarily rendering information, even though it could improve the
displayment of packages like you say.  I'd like to export more
information to a graph database, so that the packages can be searched,
explored and linked to in a graph that also contains stuff like how
programs were run and what files that run produced.

So, this is essentially an interoperability thing for communicating with
other systems.

>
>> If this sounds like a good idea I'll write a new patch.  And while I'm
>> at it, what set of commands fully cover the graph code for all node
>> types?  Just all variants in 'guix graph --type=X'?
>
> “make check TESTS=tests/graph.scm” covers all the node types I think.
>
> Ludo’.

Then I will run that command before I propose a new patch.

Kind regards,
Roel Janssen