formula.rb: define `elisp` and `opt_elisp`

Closes Homebrew/homebrew#45567.

Signed-off-by: Alex Dunn <dunn.alex@gmail.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index ffbd02cfc..d0d1e269b 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -600,6 +600,15 @@ class Formula
     prefix+"share"+name
   end
 
+  # The directory where Emacs Lisp files should be installed, with the
+  # formula name appended to avoid linking conflicts.
+  #
+  # Install an Emacs mode included with a software package:
+  # <pre>elisp.install "contrib/emacs/example-mode.el"</pre>
+  def elisp
+    prefix+"share/emacs/site-lisp"+name
+  end
+
   # The directory where the formula's Frameworks should be installed.
   # This is symlinked into `HOMEBREW_PREFIX` after installation or with
   # `brew link` for formulae that are not keg-only.
@@ -759,6 +768,10 @@ class Formula
     opt_prefix+"share"+name
   end
 
+  def opt_elisp
+    opt_prefix+"share/emacs/site-lisp"+name
+  end
+
   def opt_frameworks
     opt_prefix+"Frameworks"
   end