> Hi, > > Looking at this definition in gnu/system.scm [1] I am trying to figure > out what 'os' is: > > (define* (operating-system-kernel-arguments > os root-device #:key (version %boot-parameters-version)) > "Return all the kernel arguments, including the ones not specified > directly > by the user. VERSION should match that of the target <boot-parameters> > record > object that will contain the kernel parameters." > (append (bootable-kernel-arguments os root-device version) > (operating-system-user-kernel-arguments os))) > > The same file also contains a record definition for <operating-system> > so it seemed reasonable to assume that 'os' referred to such a > record. In fact, the second procedure inside the 'append' above, > operating-system-user-kernel-arguments, is one of the accessors [2] > (even though the name does not match the field).
Yes, it is supposed to be an <operating-system> record (of course, scheme does not enforce that in any way and it may end up being any other type during runtime if there is a bug in some other code). > In the first procedure bootable-kernel-arguments [3] however, 'os' > (which is called 'system' there) is used like a string, although inside > a gexp: > > (define* (bootable-kernel-arguments system root-device version) > "Return a list of kernel arguments (gexps) to boot SYSTEM from > ROOT-DEVICE. > VERSION is the target version of the boot-parameters record." > ;; If the version is newer than 0, we use the new style initrd parameter > ;; names, otherwise we use the legacy ones. This is to maintain backward > ;; compatibility when producing bootloader configurations for older > ;; generations. > (define version>0? (> version 0)) > (list (string-append (if version>0? "root=" "--root=") > ;; Note: Always use the DCE format because that's > what > ;; (gnu build linux-boot) expects for the 'root' > ;; kernel command-line option. > (file-system-device->string root-device > #:uuid-type 'dce)) > #~(string-append (if #$version>0? "gnu.system=" "--system=") > #$system) > #~(string-append (if #$version>0? "gnu.load=" "--load=") > #$system "/boot"))) > > I know objects in the store become paths when unquoted via '#$'. Does > that also work for Guix records declared via define-record-type* [4] > (please note the asterisk)? Thanks! The <operating-system> record is expanded to a store path because there is a (define-gexp-compiler ...) form for it in gnu/system.scm[1]. The gexp expansion mechanism is explained quite well in a "Dissecting Guix" blog post[2]. [1]: https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/system.scm#n1623 [2]: https://guix.gnu.org/en/blog/2023/dissecting-guix-part-3-g-expressions/
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