nongnu: Add emacs-eli.

* nongnu/packages/emacs.scm (emacs-eli): New variable.

nongnu/packages/emacs.scm

@@ -20,8 +20,11 @@
 (define-module (nongnu packages emacs)
   #:use-module (guix packages)
   #:use-module (guix build-system emacs)
+  #:use-module (guix build-system copy)
   #:use-module (guix download)
-  #:use-module (nonguix licenses))
+  #:use-module (guix git-download)
+  #:use-module (nonguix licenses)
+  #:use-module (nongnu packages lisp))
 
 (define-public clhs
   (package
@@ -70,3 +73,61 @@ browsing. An Emacs package is provided for easy access.  Load it with:
 @end lisp
 ")
     (license (nonfree "http://quickdocs.org/clhs/"))))
+
+(define-public emacs-eli
+  ;; 10.1 HEAD has a fix for Emacs 28.1, as opposed to the latest "express" tag.
+  (let ((commit "8f9a8b9eb1aa518774c54d51e4f38ba534356415"))
+    (package
+      (name "emacs-eli")
+      (version (git-version "acl10.1express_Feb2022update2022-02-11" "1" commit))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/franzinc/eli/")
+               (commit commit)))
+         (file-name (git-file-name "emacs-eli" version))
+         (sha256
+          (base32
+           "0w1hdkr9x3byf1l6dbcbnd4x8110wvps3527ivyj1bmdk1hyqnzb"))))
+      ;; The `emacs-build-system' fails here, probably because ELI is meant to
+      ;; be load with (load "fi-site-init.el") and not with `require'.  See
+      ;; https://franz.com/emacs/.
+      (build-system copy-build-system)
+      (inputs (list allegro-cl))
+      (arguments
+       `(#:install-plan
+         `(("." ,,(string-append "share/emacs/site-lisp/eli-" version)
+            ;; Remove useless Windows or build files.
+            #:exclude ("emacsdir.pl" "nsis" "Makefile" "local.mak")))
+         #:phases
+         (modify-phases %standard-phases
+           (add-after 'unpack 'patch-paths
+             (lambda* (#:key inputs #:allow-other-keys)
+               (let ((allegro-cl (assoc-ref inputs "allegro-cl")))
+                 ;; FIXME: Can't get `emacs-substitute-variables' to work here, why?
+                 (substitute* "fi-vars.el"
+                   (("defvar fi:common-lisp-image-name \"alisp\"")
+                    (string-append "defvar fi:common-lisp-image-name \""
+                                   allegro-cl "/bin/alisp\""))
+                   (("defvar fi:common-lisp-image-file nil")
+                    (string-append "defvar fi:common-lisp-image-file \""
+                                   allegro-cl "/share/allegro-cl/alisp.dxl\""))
+                   (("defvar fi:common-lisp-directory nil")
+                    (string-append "defvar fi:common-lisp-directory \""
+                                   allegro-cl "/share/allegro-cl\"")))))))))
+      (home-page "https://franz.com/emacs/")
+      (synopsis "Allegro Common Lisp Emacs interface")
+      (description
+       "An integral part of the Allegro CL programming environment is the interface
+between Emacs and Allegro CL, hereafter referred to as the Emacs-Lisp
+interface.  This interface allows the editing and running of Common Lisp
+programs, and contains enhancements that allow a tight coupling between Emacs
+and Lisp, very similar to those which used to be available only on Lisp
+machines.
+
+To load it, call @code{(load \"fi-site-init.el\")} from Emacs.
+Then you can start Allegro CL by entering @code{M-x fi:common-lisp}.")
+      ;; While this may be a free license, this Emacs package is only useful
+      ;; with the non-free Allegro CL.
+      (license (nonfree "https://raw.githubusercontent.com/franzinc/eli/acl10.1express_Feb2022update2022-02-11/LICENSE")))))