* emacs/guix-hydra.el (guix-hydra-job-name-specification): New procedure. * emacs/guix-ui-package.el (guix-package-info-insert-systems) (guix-package-list-latest-builds): Use it.
* emacs/guix-utils.el (guix-hexify, guix-number->bool): New procedures. (guix-while-null): New macro. * emacs/guix-hydra.el: New file. * emacs/guix-hydra-build.el: New file. * emacs/guix-hydra-jobset.el: New file. * emacs.am (ELFILES): Add them. * doc/emacs.texi (Emacs Hydra): New node. (Emacs Interface): Add it. * doc/guix.texi (Top): Add it. (Substitutes): Mention Emacs interface.