1 files changed, 48 insertions, 0 deletions
diff --git a/Library/Homebrew/cmd/missing.rb b/Library/Homebrew/cmd/missing.rb
new file mode 100644
index 000000000..26d6e3340
--- /dev/null
+++ b/Library/Homebrew/cmd/missing.rb
@@ -0,0 +1,48 @@
+require 'formula'
+require 'cmd/outdated'
+
+module Homebrew extend self
+  def installed_brews
+    formulae = []
+    HOMEBREW_CELLAR.subdirs.each do |rack|
+      f = Formula.factory rack.basename.to_s rescue nil
+      formulae << f if f and f.installed?
+    end
+    formulae
+  end
+
+  def find_missing_brews top_level
+    # Names of outdated brews; they count as installed.
+    outdated = Homebrew.outdated_brews.collect{ |b| b.name }
+
+    brews = []
+    top_level.each do |f|
+      missing_deps = f.recursive_deps.map{ |g| g.name }.uniq.reject do |dep_name|
+        Formula.factory(dep_name).installed? or outdated.include?(dep_name)
+      end
+
+      unless missing_deps.empty?
+        brews << [f.name, missing_deps]
+      end
+    end
+    brews
+  end
+
+  def missing
+    return unless HOMEBREW_CELLAR.exist?
+
+    formulae_to_check = if ARGV.named.empty?
+      installed_brews
+    else
+      ARGV.formulae
+    end
+
+    missing_deps = find_missing_brews(formulae_to_check)
+    missing_deps.each do |d|
+      name = d[0]
+      missing = d[1]
+      print "#{name}: " if formulae_to_check.size > 1
+      puts "#{missing * ' '}"
+    end
+  end
+end