brew tap and brew untap

.gitignore

@@ -7,4 +7,5 @@
 !/bin/brew
 !/share/man/man1/brew.1
 .DS_Store
-/Library/LinkedKegs
+/Library/LinkedKegs
+/Library/Taps

Library/Homebrew/cmd/tap.rb

@@ -0,0 +1,38 @@
+HOMEBREW_LIBRARY = HOMEBREW_REPOSITORY/"Library"
+
+module Homebrew extend self
+
+  def tap
+    if ARGV.empty?
+      (HOMEBREW_LIBRARY/"Taps").children.each do |tap|
+        puts tap.basename.sub('-', '/') if (tap/'.git').directory?
+      end
+    else
+      install_tap(*tap_args)
+    end
+  end
+
+  def install_tap user, repo
+    raise "brew install git" unless system "/usr/bin/which -s git"
+
+    tapd = HOMEBREW_LIBRARY/"Taps/#{user}-#{repo}"
+    raise "Already tapped!" if tapd.directory?
+    abort unless system "git clone https://github.com/#{user}/homebrew-#{repo} #{tapd}"
+
+    cd HOMEBREW_LIBRARY/"Formula"
+    tapd.find_formula do |relative_pathname|
+      # using the system ln is the only way to get relative symlinks
+      system "ln -s ../Taps/#{user}-#{repo}/#{relative_pathname} 2>/dev/null"
+      opoo "#{relative_pathname.basename(".rb")} conflicts" unless $?.success?
+    end
+  end
+
+  private
+
+  def tap_args
+    ARGV.first =~ %r{^(\w+)/(homebrew-)?(\w+)$}
+    raise "Invalid usage" unless $1 and $3
+    [$1, $3]
+  end
+
+end

Library/Homebrew/cmd/untap.rb

@@ -0,0 +1,17 @@
+require 'cmd/tap' # for Pathname.recursive_formula
+
+module Homebrew extend self
+  def untap
+    user, repo = tap_args
+    tapd = HOMEBREW_PREFIX/"Library/Taps/#{user}-#{repo}"
+
+    raise "No such tap!" unless tapd.directory?
+
+    tapd.find_formula do |pn|
+      pn = HOMEBREW_REPOSITORY/"Library/Formula"/pn.basename
+      pn.delete if pn.symlink? and pn.realpath.to_s =~ %r[^#{tapd.realpath}]
+    end
+
+    rm_rf tapd
+  end
+end

Library/Homebrew/extend/pathname.rb

@@ -313,6 +313,17 @@ class Pathname
     end
     system '/usr/bin/install-info', '--delete', '--quiet', self.to_s, (self.dirname+'dir').to_s
   end
+
+  def find_formula pwd = self
+    children.map{ |child| child.relative_path_from(pwd) }.each do |pn|
+      yield pn if pn.to_s =~ /.rb$/
+    end
+    children.each do |child|
+      child.find_formula(pwd) do |pn|
+        yield pn
+      end if child.directory?
+    end
+  end
 end
 
 # sets $n and $d so you can observe creation of stuff