Re: How do I build a derivation with guix build?

[Timothy Sample]

Hi divoplade,

As I understand it, ‘gexp->derivation’ returns a value in the store
monad.  I’m not sure why ‘guix build’ doesn’t know how to use it
directly, but you can get at the derivation by wrapping it with
‘run-with-store’:

    (run-with-store (open-connection)
      (gexp->derivation "the-thing" build-exp))

Don’t forget to use the ‘(guix store)’ module for this.

But!  There’s a better way!!  :)

You can use the “declarative interface”.  Just replace
‘gexp->derivation’ with ‘computed-file’:

    (computed-file "the-thing" build-exp)

Now there’s no need for ‘(guix store)’.

HTH!


-- Tim

divoplade <d@divoplade.fr> writes:

> Hello,
>
> I am still learning how to use gexps, and I thought that running this
> would work:
>
> guix build -f example.scm
>
> with example.scm containing:
>
> (use-modules (gnu packages base))
> (use-modules (guix gexp))
>
> (define build-exp
>   #~(begin
>       (mkdir #$output)
>       (chdir #$output)
>       (symlink (string-append #$coreutils "/bin/ls")
>                "list-files")))
>
> (gexp->derivation "the-thing" build-exp)
>
> This is a copy of what's on the manual for explaining G-expressions.
>
> The guix build -f command should, according to the --help output:
> "build the package or derivation that the code within FILE evaluates
> to"
>
> However, I get an exception, "Wrong number of arguments to #<procedure
> 7f775f854f00 at guix/gexp.scm:1064:2 (state)>", after a backtrace that
> does not even contains example.scm.
>
> What is going on? How do you build the derivation?
>
> Best regards,
>
> divoplade