Proof General 4.1

Closes Homebrew/homebrew#14827.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/proof-general.rb

@@ -0,0 +1,64 @@
+require 'formula'
+
+class ProofGeneral < Formula
+  homepage 'http://proofgeneral.inf.ed.ac.uk'
+  url 'http://proofgeneral.inf.ed.ac.uk/releases/ProofGeneral-4.1.tgz'
+  sha1 '0dd18bd0bdad8faab76f61bffc8e432c3ed7aeaf'
+
+  option 'with-doc', 'Install documentations'
+  option 'with-emacs=</path/to/emacs>', 'Re-compile the lisp files with a specified emacs'
+
+  def which_emacs
+    ARGV.each do |a|
+      if a.index('--with-emacs')
+        emacs = a.sub('--with-emacs=', '')
+        raise "#{emacs} not found" if not File.exists? "#{emacs}"
+        ohai "Use Emacs: #{emacs}"
+
+        version = `#{emacs} --version | grep -Eo "GNU Emacs \\d+(\\.\\d+)+"`.gsub /\n/, ""
+        ohai "Emacs version: #{version}"
+        major = `echo "#{version}" | awk {'print $3'} | cut -d "." -f 1`.gsub /\n/, ""
+        raise "Only Emacs of major version 23 is supported." if major != "23"
+        return emacs
+      end
+    end
+    return ""
+  end
+
+  def install
+    emacs = which_emacs
+    args = ["PREFIX=#{prefix}",
+            "DEST_PREFIX=#{prefix}",
+            "ELISPP=share/emacs/site-lisp/ProofGeneral",
+            "ELISP_START=#{share}/emacs/site-lisp/site-start.d",
+            "EMACS=#{emacs}"];
+
+    Dir.chdir "ProofGeneral" do
+      if emacs != ""
+        system "make clean"
+        system "make", "compile", *args
+      end
+      system "make", "install", *args
+      man1.install "doc/proofgeneral.1"
+      info.install "doc/ProofGeneral.info", "doc/PG-adapting.info"
+
+      doc.install "doc/ProofGeneral", "doc/PG-adapting" if build.include? 'with-doc'
+    end
+  end
+
+  def caveats
+    doc = ""
+    if build.include? 'with-doc'
+      doc += <<-EOS.undent
+         The HTML documentations are available in:
+               #{HOMEBREW_PREFIX}/share/doc/proof-general
+      EOS
+    end
+
+    <<-EOS.undent
+    To use ProofGeneral with Emacs, add the following line to your ~/.emacs file:
+      (load-file "#{HOMEBREW_PREFIX}/share/emacs/site-lisp/ProofGeneral/generic/proof-site.el")
+    #{doc}
+    EOS
+  end
+end