Re: Early feedback on Guix Home

[Andrew Tropin]

Ludovic Courtès <ludo@gnu.org> writes:

> Hi,
>
> (Sorry for the late reply…)
>
> Andrew Tropin <andrew@trop.in> skribis:
>
>> Ludovic Courtès <ludo@gnu.org> writes:
>
> [...]
>
>>>>> Possible action:
>>>>>
>>>>>   1. Change config records to accept file-like objects instead of
>>>>>      strings.  That way, users can choose to have snippets inlined (in a
>>>>>      ‘plain-file’ object) or separate (via ‘local-file’).  See for
>>>>>      example how ‘tor-configuration->torrc’ does it.
>>>>
>>>> Yeah, there is a ‘slurp-file-gexp’ procedure that let’s one read an
>>>> extenal file, but using existing APIs like ‘local-file’ is probably a
>>>> better idea.
>>>
>>> Yes, it feels more natural.  Also, ‘slurp-file-gexp’ returns a gexp (a
>>> code snippet), but as a user you don’t know where that snippet is going
>>> to be inserted; it may not work in some contexts.
>>
>> Acually, the idea behind `slurp-file-gexp` is that you always know where
>> it will be inserted, because it will be inside the specific section of
>> the configuration.  Take a look at emacs home-service example:
>> https://git.sr.ht/~abcdw/rde/tree/master/item/gnu/home-services/emacs.scm#L91
>
> What I mean is that, in a general sense, one cannot know whether the
> gexp will be inserted in a place where it’s “valid”.  Consider the
> following examples, where the gexp is meant to be inserted in lieu of
> “PLACEHOLDER”:
>
>   #~(list '(#$PLACEHOLDER))  ;it’s quoted
>
>   #~(let ((call-with-input-file (const #f)))
>       #$PLACEHOLDER)
>
> These are “hygiene” problems discussed in the “Code Staging in GNU Guix”
> paper.
>
> All this to say that, from an API viewpoint, I think it’s (1) more
> robust, as I wrote, and (2) clearer to expect file-like objects in such
> places.  It’s clearer because users can be expected to have an
> understanding of what ‘local-file’ does, whereas ‘slurp-file-gexp’ is
> more involved.
>
> I hope this clarifies what I had in mind!
>
> Ludo’.

Got the problem.  Will take a closer look, when will be preparing this
code for upstreaming and maybe will reconsider the approach or will rise
another discussion on that.  Also, need to schedule a reading of your
paper on gexps)

Thank you for clarification!)

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