GNU bug report logs - #50286
[RFC PATCH] Let 'package-location' returns location of surrounding 'let'.

Previous Next

Full log

View this message in rfc822 format

From: Ludovic Courtès <ludo <at> gnu.org>
To: Maxime Devos <maximedevos <at> telenet.be>
Cc: iskarian <at> mgsn.dev, 50286 <at> debbugs.gnu.org
Subject: [bug#50286] [RFC PATCH] Let 'package-location' returns location of surrounding 'let'.
Date: Wed, 08 Sep 2021 15:38:39 +0200

Hello,

Maxime Devos <maximedevos <at> telenet.be> skribis:

> Why not always let the location of a package be the location of the
> surrounding define-public* form, instead of having two separate
> locations?  Letting the location of a package be the location of the
> define-public* form (or 'let' form) seems more useful to people using
> "guix edit minetest-etheral" for example, and the package-field-location
> code can easily be adjusted to support 'define-public*' (or let) forms.
>
> If two separate package-definition-location and package-location are
> introduced, what should "guix show minetest-ethereal" show?  The location
> of the 'package' form, the location of the 'let' form or the location
> of the 'define-public' form?

A package always has a ‘location’, but it may lack a definition
location, for instance if it’s produced by a procedure, or if it’s not
bound to a top-level variable.

Things like ‘package-field-location’ are likely more accurate if they
start searching from the beginning of the (package …) sexp.

These patches leave the UIs unchanged (‘guix show’, ‘guix edit’, etc.)
because I think ‘location’ is good for these.

> Having two separate define-public* and define-public macros might be a
> little confusing.  Would it be possible to let 'define-public*' replace
> 'define-public'?

‘define-public*’ is exported as ‘define-public’, so package definitions
do not need to be changed:

  #:replace ((define-public* . define-public))

> I don't really have an opinion on whether package-[field-]location should
> return the location of the 'let' form or the location of the 'define-public'
> form.  I think 'package-location' should return the location of the 'let'
> form (or a surrounding form), because the 'commit' and 'version' variable
> from the 'let' form are part of the package -- change them, and you'll
> get a different package.

Yeah, I see what you mean.  The work ‘guix refresh -u’ and ‘guix style’
do is essentially correlating live objects (package records) to their
source code.  This is necessarily an approximation; it’s similar to
version strings constructed with ‘string-append’: that’s something that
inspection of the live object cannot reveal, so we use heuristic to
match common conventions.

Thoughts?

Thanks,
Ludo’.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.