Dependency resolution with fancy syntax

Is it a DSL? No. But people call it that apparently.

To add a dependency:

class Doe <Formula
  depends_on 'ray'
  depends_on 'mee' => :optional
  depends_on 'far' => :recommended
  depends_on Sew.new
end

Sew would be a formula you have defined in this Formula file. This is useful,
eg. see Python's formula. Formula specified in this fashion cannot be linked
into the HOMEBREW_PREFIX, they are considered private libraries. This allows
you to create custom installations that are very specific to your formula.

More features to come, like specifying versions

22 files changed, 93 insertions, 106 deletions

diff --git a/Library/Formula/erlang.rb b/Library/Formula/erlang.rb
index eaa002ba0..41feea372 100644
--- a/Library/Formula/erlang.rb
+++ b/Library/Formula/erlang.rb
@@ -13,6 +13,9 @@ class Erlang <Formula
   @url='http://erlang.org/download/otp_src_R13B01.tar.gz'
   @md5='b3db581de6c13e1ec93d74e54a7b4231'
 
+  depends_on 'icu4c'
+  depends_on 'openssl'
+
   def install
     ENV.deparallelize
     system "./configure", "--disable-debug",
diff --git a/Library/Formula/fish.rb b/Library/Formula/fish.rb
index 09246747e..0324f0259 100644
--- a/Library/Formula/fish.rb
+++ b/Library/Formula/fish.rb
@@ -5,9 +5,7 @@ class Fish <Formula
   @homepage='http:://fishshell.org/'
   @md5='4b2436843e63bebba467cc4add11428a'
 
-  def deps
-    'readline'
-  end
+  depends_on 'readline'
 
   def install
     system "./configure", "--prefix=#{prefix}", "--without-xsel"
diff --git a/Library/Formula/glib.rb b/Library/Formula/glib.rb
index 9befe40c1..24c55be41 100644
--- a/Library/Formula/glib.rb
+++ b/Library/Formula/glib.rb
@@ -5,10 +5,8 @@ class Glib <Formula
   @md5='4c178b91d82ef80a2da3c26b772569c0'
   @homepage='http://www.gtk.org'
 
-  def deps
-    BinaryDep.new 'pkg-config'
-    LibraryDep.new 'gettext'
-  end
+  depends_on 'pkg-config'
+  depends_on 'gettext'
 
   def install
     # indeed, amazingly, -w causes gcc to emit spurious errors for this package!
diff --git a/Library/Formula/imagemagick.rb b/Library/Formula/imagemagick.rb
index ee06a50ac..0a7469b8a 100644
--- a/Library/Formula/imagemagick.rb
+++ b/Library/Formula/imagemagick.rb
@@ -7,9 +7,11 @@ class Imagemagick <Formula
   @md5='8cb7471a50428e4892ee46aa404e54c2'
   @homepage='http://www.imagemagick.org'
 
-  def deps
-    { :required => 'jpeg', :optional => %w[libwmf libtiff little-cms ghostscript] }
-  end
+  depends_on 'jpeg'
+  depends_on 'libwmf' => :optional
+  depends_on 'libtiff' => :optional
+  depends_on 'little-cms' => :optional
+  depends_on 'ghostscript' => :recommended
 
   def install
     ENV.libpng
@@ -25,15 +27,14 @@ class Imagemagick <Formula
                           "--without-maximum-compile-warnings",
                           "--prefix=#{prefix}",
                           "--disable-osx-universal-binary",
-                          "--with-gs-font-dir=#{prefix}/share/ghostscript/fonts",
+                          "--with-gs-font-dir=#{HOMEBREW_PREFIX}/share/ghostscript/fonts",
                           "--without-perl" # I couldn't make this compile
     system "make install"
 
-    # We already copy these in
-    d=prefix+'share'
-    (d+'NEWS.txt').unlink
-    (d+'LICENSE').unlink
-    (d+'ChangeLog').unlink
+    # We already copy these into the keg root
+    (share+'NEWS.txt').unlink
+    (share+'LICENSE').unlink
+    (share+'ChangeLog').unlink
   end
 
   def caveats
diff --git a/Library/Formula/liblastfm.rb b/Library/Formula/liblastfm.rb
index ea6a61706..fabdf637b 100644
--- a/Library/Formula/liblastfm.rb
+++ b/Library/Formula/liblastfm.rb
@@ -5,9 +5,9 @@ class Liblastfm <Formula
   @url='http://static.last.fm/src/liblastfm-0.3.0.tar.bz2'
   @md5='3f73222ebc31635941832b01e7a494b6'
 
-  def deps
-    %w[qt fftw samplerate]
-  end
+  depends_on 'qt'
+  depends_on 'fftw'
+  depends_on 'samplerate'
 
   def install
     system "./configure --release --prefix '#{prefix}'"
diff --git a/Library/Formula/libmusicbrainz.rb b/Library/Formula/libmusicbrainz.rb
index b9d5c1c45..b7869abca 100644
--- a/Library/Formula/libmusicbrainz.rb
+++ b/Library/Formula/libmusicbrainz.rb
@@ -5,9 +5,8 @@ class Libmusicbrainz <Formula
   @homepage='http://musicbrainz.org'
   @md5='648ecd43f7b80852419aaf73702bc23f'
 
-  def deps
-    { :required => 'neon', :optional => 'libdiscid' }
-  end
+  depends_on 'neon'
+  depends_on 'libdiscid' => :optional
 
   def install
     system "cmake . #{std_cmake_parameters}"
diff --git a/Library/Formula/libvorbis.rb b/Library/Formula/libvorbis.rb
index cdd795437..d4ca863e8 100644
--- a/Library/Formula/libvorbis.rb
+++ b/Library/Formula/libvorbis.rb
@@ -5,9 +5,7 @@ class Libvorbis <Formula
   @md5='6a7086ee666b8c62e122d29d107f7bec'
   @homepage='http://vorbis.com'
 
-  def deps
-    'libogg'
-  end
+  depends_on 'libogg'
 
   def install
     system "./configure --enable-docs --disable-debug --disable-dependency-tracking --prefix='#{prefix}'"
diff --git a/Library/Formula/memcached.rb b/Library/Formula/memcached.rb
index 0ad5681c3..3b942615f 100644
--- a/Library/Formula/memcached.rb
+++ b/Library/Formula/memcached.rb
@@ -5,9 +5,7 @@ class Memcached <Formula
   @homepage='http://www.danga.com/memcached/'
   @md5='d7651ecb8bf345144cb17900d9a46c85'
 
-  def deps
-    'libevent'
-  end
+  depends_on 'libevent'
 
   def install
     system "./configure --prefix='#{prefix}'"
diff --git a/Library/Formula/mysql-connector-c.rb b/Library/Formula/mysql-connector-c.rb
index f135f7dc8..580b6f5a6 100644
--- a/Library/Formula/mysql-connector-c.rb
+++ b/Library/Formula/mysql-connector-c.rb
@@ -5,9 +5,7 @@ class MysqlConnectorC <Formula
   @url='http://mysql.llarian.net/Downloads/Connector-C/mysql-connector-c-6.0.1.tar.gz'
   @md5='348a869fa72957062ea4e7ad3865623c'
 
-  def deps
-    'cmake'
-  end
+  depends_on 'cmake'
 
   def install
     system "cmake . #{std_cmake_parameters}"
diff --git a/Library/Formula/mysql.rb b/Library/Formula/mysql.rb
index 5cfb8be41..76fd2a7c4 100644
--- a/Library/Formula/mysql.rb
+++ b/Library/Formula/mysql.rb
@@ -5,9 +5,7 @@ class Mysql <Formula
   @homepage='http://dev.mysql.com/doc/refman/5.1/en/'
   @md5='7564d7759a8077b3a0e6190955422287'
 
-  def deps
-    'readline'
-  end
+  depends_on 'readline'
 
   def options
     [
diff --git a/Library/Formula/nginx.rb b/Library/Formula/nginx.rb
index 4863381e6..d0f03666b 100644
--- a/Library/Formula/nginx.rb
+++ b/Library/Formula/nginx.rb
@@ -5,9 +5,7 @@ class Nginx <Formula
   @homepage='http://nginx.net/'
   @md5='6ebf89b9b00a3b82734e93c32da7df07'
 
-  def deps
-    'pcre'
-  end
+  depends_on 'pcre'
     
   def install
     system "./configure", "--prefix=#{prefix}", "--with-http_ssl_module"
diff --git a/Library/Formula/playdar.rb b/Library/Formula/playdar.rb
index 44b1f815d..5ec5c0639 100644
--- a/Library/Formula/playdar.rb
+++ b/Library/Formula/playdar.rb
@@ -4,9 +4,9 @@ class Playdar <Formula
   @homepage='http://www.playdar.org'
   @head='git://github.com/mxcl/playdar.git'
 
-  def deps
-    %w[taglib boost cmake]
-  end
+  depends_on 'taglib'
+  depends_on 'boost'
+  depends_on 'cmake'
 
   def skip_clean? path
     # for some reason stripping breaks it
diff --git a/Library/Formula/python.rb b/Library/Formula/python.rb
index 6d92d147c..c1d15a887 100644
--- a/Library/Formula/python.rb
+++ b/Library/Formula/python.rb
@@ -26,10 +26,8 @@ class Python <Formula
   @homepage='http://www.python.org/'
   @md5='245db9f1e0f09ab7e0faaa0cf7301011'
 
-  def deps
-    # You can build Python without readline, but you really don't want to.
-    Readline.new
-  end
+  # You can build Python without readline, but you really don't want to.
+  depends_on Readline.new
 
   def skip_clean? path
     path == bin+'python' or path == bin+'python2.6' or # if you strip these, it can't load modules
diff --git a/Library/Formula/scummvm.rb b/Library/Formula/scummvm.rb
index adb1f1a48..912c4207e 100644
--- a/Library/Formula/scummvm.rb
+++ b/Library/Formula/scummvm.rb
@@ -13,9 +13,10 @@ prefer to use theirs. If so type `brew home scummvm' to visit their site.
     EOS
   end
 
-  def deps
-    { :required => 'sdl', :recommended => %w[flac libogg libvorbis] }
-  end
+  depends_on 'sdl'
+  depends_on 'flac' => :recommended
+  depends_on 'libvorbis' => :recommended
+  depends_on 'libogg' => :recommended
 
   def install
     system "./configure --prefix='#{prefix}' --disable-debug"
diff --git a/Library/Formula/sshfs.rb b/Library/Formula/sshfs.rb
index 0ae3f40d9..59c184663 100644
--- a/Library/Formula/sshfs.rb
+++ b/Library/Formula/sshfs.rb
@@ -13,9 +13,9 @@ class Sshfs <Formula
     }
   end
 
-  def deps
-    %w[pkg-config glib macfuse]
-  end
+  depends_on 'pkg-config'
+  depends_on 'glib'
+  depends_on 'macfuse'
 
   def install
     # Steal compile flags from macfuse_buildtool.sh
diff --git a/Library/Formula/subversion.rb b/Library/Formula/subversion.rb
index 63254e746..e4584062e 100644
--- a/Library/Formula/subversion.rb
+++ b/Library/Formula/subversion.rb
@@ -1,22 +1,13 @@
 require 'brewkit'
 
-class SubversionDeps <Formula
-  @url='http://subversion.tigris.org/downloads/subversion-deps-1.6.5.tar.bz2'
-  @md5='8272316e1670d4d2bea451411e438bde'
-end
-
 class Subversion <Formula
   @url='http://subversion.tigris.org/downloads/subversion-1.6.5.tar.bz2'
   @homepage='http://subversion.tigris.org/'
   @md5='1a53a0e72bee0bf814f4da83a9b6a636'
 
-  def install
-    # Slot dependencies into place
-    d=Pathname.getwd
-    SubversionDeps.new.brew do
-      d.install Dir['*']
-    end
+  depends_on 'neon'
 
+  def install
     # Use existing system zlib, dep-provided other libraries
     # Don't mess with Apache modules (since we're not sudo)
     system "./configure", "--disable-debug",
diff --git a/Library/Formula/unp.rb b/Library/Formula/unp.rb
index 83cd639c2..d01b7a36e 100644
--- a/Library/Formula/unp.rb
+++ b/Library/Formula/unp.rb
@@ -5,9 +5,7 @@ class Unp <Formula
   @homepage='http://packages.debian.org/de/etch/unp'
   @md5='ecea662bd7e7efe7f7e2213bf21d9646'
 
- def deps
-   'p7zip'
- end
+  depends_on 'p7zip'
 
   def install
     bin.install %w[unp ucat]
diff --git a/Library/Formula/vorbis-tools.rb b/Library/Formula/vorbis-tools.rb
index b057cbe18..deaa2d403 100644
--- a/Library/Formula/vorbis-tools.rb
+++ b/Library/Formula/vorbis-tools.rb
@@ -5,9 +5,10 @@ class VorbisTools <Formula
   @md5='df976d24e51ef3d87cd462edf747bf9a'
   @homepage='http://vorbis.com'
 
-  def deps
-    { :required => %w[ogg vorbis], :optional => %w[ao ogg123] }
-  end
+  depends_on 'ogg'
+  depends_on 'vorbis'
+  depends_on 'ao' => :optional
+  depends_on 'ogg123' => :optional
 
   def install
     system "./configure --disable-debug --disable-nls --disable-dependency-tracking --prefix='#{prefix}'"
diff --git a/Library/Formula/yajl.rb b/Library/Formula/yajl.rb
index 19f47f2ff..f47a454e4 100644
--- a/Library/Formula/yajl.rb
+++ b/Library/Formula/yajl.rb
@@ -5,9 +5,7 @@ class Yajl <Formula
   @url='http://github.com/lloyd/yajl/tarball/1.0.5'
   @md5='f4a3cbc764c43231ed1aedc54438b69b'
 
-  def deps
-    'cmake'
-  end
+  depends_on 'cmake'
 
   def install
     ENV.deparallelize
diff --git a/Library/Homebrew/brew.h.rb b/Library/Homebrew/brew.h.rb
index 875f61be0..0d977ae95 100644
--- a/Library/Homebrew/brew.h.rb
+++ b/Library/Homebrew/brew.h.rb
@@ -144,31 +144,12 @@ def clean f
 end
 
 
-# NOTE this is ugly code, and inefficient too, and can have infinite cycles
-# I have no time currently to improve it, feel free to submit a more elegant
-# solution. Thanks! --mxcl
-def expand_deps fae
+def expand_deps ff
   deps = []
-  fae.each do |f|
-    case f.deps
-    when String, Array
-      f.deps.each do |name|
-        f = Formula.factory name
-        deps << expand_deps(f) if f.deps # hideous inefficient
-        deps << f unless f.installed?
-      end
-    when Hash
-      # TODO implement optional and recommended
-      names = []
-      f.deps.each_value {|v| names << v}
-      ff=names.flatten.collect {|name| Formula.factory name}
-      deps << expand_deps(ff)
-    end
-    deps << f
+  ff.deps.collect do |f|
+    deps += expand_deps(Formula.factory(f))
   end
-
-  # TODO much more efficient to use a set and not recurse stuff already done
-  return deps.flatten.uniq
+  deps << ff
 end
 
 
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 9c5123545..a4bebdd2b 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -114,8 +114,6 @@ class Formula
   #     :p2 => ['http://moo.com/patch5', 'http://moo.com/patch6']
   #   }
   def patches; [] end
-  # reimplement and specify dependencies
-  def deps; end
   # sometimes the clean process breaks things, return true to skip anything
   def skip_clean? path; false end
 
@@ -157,6 +155,7 @@ class Formula
   end
 
   def self.factory name
+    return name if name.kind_of? Formula
     require self.path(name)
     return eval(self.class(name)).new(name)
   rescue LoadError
@@ -167,6 +166,10 @@ class Formula
     HOMEBREW_PREFIX+'Library'+'Formula'+"#{name.downcase}.rb"
   end
 
+  def deps
+    self.class.deps or []
+  end
+
 protected
   # Pretty titles the command and buffers stdout/stderr
   # Throws if there's an error
@@ -280,9 +283,31 @@ private
   end
 
   class <<self
-    attr_reader :url, :version, :homepage, :head
+    attr_reader :url, :version, :homepage, :head, :deps
     attr_reader *CHECKSUM_TYPES
-  end
+
+    def depends_on name, *args
+      @deps ||= []
+
+      case name
+      when String
+        # noop
+      when Hash
+        name = name.keys.first # indeed, we only support one mapping
+      when Symbol
+        name = name.to_s
+      when Formula
+        @deps << name
+        return # we trust formula dev to not dupe their own instantiations
+      else
+        raise "Unsupported type #{name.class}"
+      end
+
+      # we get duplicates because every new fork of this process repeats this
+      # step for some reason I am not sure about
+      @deps << name unless @deps.include? name
+    end
+  end  
 end
 
 # see ack.rb for an example usage
diff --git a/bin/brew b/bin/brew
index bf3a449c2..722544615 100755
--- a/bin/brew
+++ b/bin/brew
@@ -38,6 +38,7 @@ unless system "which -s gcc-4.2" and $?.success?
   abort "Sorry, Homebrew requires gcc 4.2, which is provided by Xcode 3.1"
 end
 
+
 begin
   case ARGV.shift
     when '--prefix' then puts HOMEBREW_PREFIX
@@ -104,7 +105,7 @@ begin
         unless system "which #{ENV['CC'] or 'cc'} &> /dev/null" and $?.success?
           raise "We cannot find a c compiler, have you installed the latest Xcode?"
         end
-        fae = ARGV.formulae.reject do |f|
+        formulae = ARGV.formulae.reject do |f|
           if f.installed?
             message = "Formula already installed: #{f.prefix}"
             if ARGV.formulae.count > 1
@@ -115,20 +116,24 @@ begin
             true
           end
         end
-        exit 0 if fae.empty?
+        exit 0 if formulae.empty?
       else
-        fae=ARGV.formulae
+        formulae = ARGV.formulae
       end
 
-      # the resulting order will be optimal for super-deps and deps
-      fae=expand_deps fae
+      deps = []
+      formulae.each { |f| deps += expand_deps f }
+      formulae = deps.reject { |f| f.installed? }
 
-      require 'beer_events'
+      require 'set'
+      done = Set.new
 
+      require 'beer_events'
       watch_out_for_spill do
-        fae.each do |f|
-          # we need to ensure a pristine ENV for each process or the formula
-          # will start with the ENV from the previous build
+        formulae.each do |f|
+          next if done.include? f.class
+          done << f.class
+
           pid=fork
           if pid.nil?
             exec __FILE__, "install-just-one", f.name, *ARGV.options