New command 'brew deps [formula]'

Where brew info will show the next-level-down dependencies, brew deps
will show all of the formulae that a given formula depends on.

Library/Homebrew/formula.rb

@@ -38,10 +38,25 @@ class Formulary
   # Returns all formula names as strings, with or without aliases
   def self.names with_aliases=false
     everything = (HOMEBREW_REPOSITORY+'Library/Formula').children.map{|f| f.basename('.rb').to_s }
-    everything.push *Formulary.get_aliases.keys if with_aliases
+    if with_aliases
+      everything.push *Formulary.get_aliases.keys
+    end
     everything.sort
   end
   
+  def self.read name
+    Formulary.names.each do |f|
+      next if f != name
+
+      require Formula.path(name)
+      klass_name = Formula.class_s(name)
+      klass = eval(klass_name)
+      return klass        
+    end
+    
+    return nil
+  end
+  
   # Loads all formula classes.
   def self.read_all
     Formulary.names.each do |name|

bin/brew

@@ -247,6 +247,35 @@ begin
       end
     end
     
+  when 'deps'
+    require 'formula'
+
+    ARGV.formulae.each do |f|
+      name = f.name
+
+      our_deps = []
+      checked = {}
+      to_check = [name]
+
+      while ! to_check.empty?
+        item = to_check.pop
+        checked[item] = true
+        
+        formula = Formulary.read item
+        next if formula == nil || formula.deps == nil || formula.deps.empty?
+        
+        our_deps.push(*formula.deps)
+        to_check.push(*formula.deps.select{|g| !checked[g]})
+      end
+      
+      if our_deps.empty?
+        puts "#{name} has no dependencies."
+      else
+        our_deps.sort!
+        puts "#{name} depends on #{our_deps.join(", ")}"
+      end
+    end
+
   when 'pull', 'push', 'checkout', 'branch'
     onoe "Unknown command: #{arg} (did you mean 'git #{arg}'?)"