Re: Article: Playing with Guix REPL from scratch

[swedebugia <swedebugia@riseup.net>]

On 2018-12-25 12:47, swedebugia wrote:
> Hi people
> 
> Today I wrote this draft blog post while playing around:
> 
> Playing with Guix REPL from scratch
> 
> This is a small example of how to quickly get an environment to play 
> with Guix in guile.
> 
> First setup your environment.
> 
> I choose a x86_64 PC and booted up the installer from an usb stick.
> 
> This is a nice environment because it already is running GuixSD in a
> console and you have are in Guix land with 8500 packages at your
> fingertips.
> 
> I started by installing a sensible array of packages:
> 
>   $ guix package -i emacs-no-x lynx git-minimal guile-readline
> guile-colorized emacs-paredit nss-certs
> 
> To set this up as intended then run:
> 
>   $ export
> GUILE_LOAD_PATH=$HOME/.guix-profile/share/guile/site/2.2:/run/current-system/profile/share/guile/site/2.2 
> 
>   $ export SSL_CERT_DIR=/root/.guix-profile/etc/ssl/certs
> 
> Now fire up the guix repl with
> 
>   $guix repl
> 
> Load e.g. this to start hacking on package records:
> 
> (use-modules
>      (guix packages)
>      (guix import utils)
>      (gnu)
>      (gnu packages sync))
> 
> Now you can start hacking on all packages in sync.scm using Scheme
> procedures from (gnu packages) (see the source of this module for
> details or guess and press tab)
> 
> E.g. (package<TAB><TAB> shows this list of nice procedures availiable:
> package
> package->cross-derivation
> package->definition
> package->derivation
> package-build-system
> package-cross-build-system-error?
> package-cross-derivation
> package-derivation
> package-description
> package-direct-inputs
> package-direct-sources
> package-error-invalid-input
> package-error-package
> package-error?
> package-field-location
> package-file
> package-full-name
> package-grafts
> package-home-page
> package-input-error?
> package-input-rewriting
> package-inputs
> package-license
> package-location
> package-maintainers
> package-mapping
> package-name
> package-native-inputs
> package-native-search-paths
> package-output
> package-outputs
> package-patched-vulnerabilities
> package-propagated-inputs
> package-properties
> package-search-paths
> package-source
> package-source-derivation
> package-superseded
> package-supported-systems
> package-synopsis
> package-transitive-inputs
> package-transitive-native-inputs
> package-transitive-native-search-paths
> package-transitive-propagated-inputs
> package-transitive-sources
> package-transitive-supported-systems
> package-transitive-target-inputs
> package-upstream-name
> package-version
> package/inherit
> package?
> 
> In addition to this there are the following origin-record-procedures:
> 
> E.g. (origin<TAB><TAB> shows this list
> origin
> origin->derivation
> origin-actual-file-name
> origin-file-name
> origin-method
> origin-modules
> origin-patch-flags
> origin-patch-guile
> origin-patch-inputs
> origin-patches
> origin-sha256
> origin-snippet
> origin-uri
> origin?
> 
> What can we do with this you might ask?
> 
> Well how about getting the url of a specific package?
> 
> scheme@(guix-user)> (origin-uri (package-source lsyncd))
> $4 = "https://github.com/axkibe/lsyncd/archive/release-2.2.2.tar.gz"
> 
> Fetching it?
> 
> scheme@(guix-user)> (url-fetch
>               (origin-uri (package-source lsyncd)) "temp")
> 
> Starting download of temp
>  From https://github.com/axkibe/lsyncd/archive/release-2.2.2.tar.gz...
> following redirection to
> `https://codeload.github.com/axkibe/lsyncd/tar.gz/release-2.2.2'...
>   release-2.2.2.tar.gz                         253KiB/s 00:00 | 80KiB
>   transferred
>   $3 = "temp"
> 
> With fold-packages you can walk through the whole stack of package
> records if you would like and count say the number of packages with
> the prefix "python-":
> 
> scheme@(guile-user)> (define snakes
>                         (fold-packages
>                              (lambda (package lst)
>                                    (if (string-prefix? "python"
>                                        (package-name package))
>                         (cons package lst)
>                   lst))
>              '()))
> 
> Now we can work on this list. As of writing this we have this many
> items in the list:
> 
> scheme@(guix-user)> (length snakes)
> $5 = 1532
> 
> scheme@(guile-user)> (define snakes
>                         (fold-packages
>                              (lambda (package lst)
>                                    (if (string-prefix? "python"
>                                        (package-name package))
>                         (cons (origin-url package) lst)
>                   lst))
>              '()))
> 
> If you create something worth saving, mount an USB stick or a harddisk
> partition and save it there.

FYI:
I would like to publish it in the guix blog when it is ready. I 
published it here just to get comments/review as it is my first post to 
the blog :-)

-- Cheers Swedebugia

-- 
Cheers Swedebugia