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 #$coreutils "/bin/ls") "list-files"))) (gexp->derivation "the-thing" build-exp) This is a copy of what's on the manual for explaining G-expressions. The guix build -f command should, according to the --help output: "build the package or derivation that the code within FILE evaluates to" However, I get an exception, "Wrong number of arguments to #<procedure 7f775f854f00 at guix/gexp.scm:1064:2 (state)>", after a backtrace that does not even contains example.scm. What is going on? How do you build the derivation? Best regards, divoplade
Hi divoplade,
As I understand it, ‘gexp->derivation’ returns a value in the store
monad. I’m not sure why ‘guix build’ doesn’t know how to use it
directly, but you can get at the derivation by wrapping it with
‘run-with-store’:
(run-with-store (open-connection)
(gexp->derivation "the-thing" build-exp))
Don’t forget to use the ‘(guix store)’ module for this.
But! There’s a better way!! :)
You can use the “declarative interface”. Just replace
‘gexp->derivation’ with ‘computed-file’:
(computed-file "the-thing" build-exp)
Now there’s no need for ‘(guix store)’.
HTH!
-- Tim
divoplade <d@divoplade.fr> writes:
> Hello,
>
> I am still learning how to use gexps, and I thought that running this
> would work:
>
> guix build -f example.scm
>
> with example.scm containing:
>
> (use-modules (gnu packages base))
> (use-modules (guix gexp))
>
> (define build-exp
> #~(begin
> (mkdir #$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
Hello, Le samedi 05 septembre 2020 à 22:40 -0400, Timothy Sample a écrit : > 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. OK, I think I understand: "you exit a monad like you exit a building on fire: by running" So, I cannot simply return a monadic value to guix build. It needs a real value. > > 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)’. Thank you, that was exactly what I was looking for! divoplade