A Dependency can point to an external podspec or define a Specification inline.

lib/cocoapods/dependency.rb

@@ -7,13 +7,41 @@ module Pod
     attr_accessor :only_part_of_other_pod
     alias_method :only_part_of_other_pod?, :only_part_of_other_pod
 
-    def initialize(name, *version_requirements)
-      super
+    attr_accessor :external_spec_source
+
+    attr_accessor :specification
+
+    def initialize(*name_and_version_requirements, &block)
+      if name_and_version_requirements.empty? && block
+        @specification = Specification.new(&block)
+        super(@specification.name, @specification.version)
+
+      elsif !name_and_version_requirements.empty? && block.nil?
+        if name_and_version_requirements.last.is_a?(Hash)
+          @external_spec_source = name_and_version_requirements.pop
+        end
+        super(name_and_version_requirements.first)
+
+      else
+        raise Informative, "A dependency needs either a name and version requirements, " \
+                           "a source hash, or a block which defines a podspec."
+      end
       @only_part_of_other_pod = false
     end
 
     def ==(other)
-      super && @only_part_of_other_pod == other.only_part_of_other_pod
+      super &&
+        @only_part_of_other_pod == other.only_part_of_other_pod &&
+          @external_spec_source == other.external_spec_source &&
+                 @specification == other.specification
+    end
+
+    def external_podspec?
+      !@external_spec_source.nil?
+    end
+
+    def inline_podspec?
+      !@specification.nil?
     end
 
     # Taken from a newer version of RubyGems

lib/cocoapods/podfile.rb

@@ -77,8 +77,68 @@ module Pod
     #
     # * http://semver.org
     # * http://docs.rubygems.org/read/chapter/7
-    def dependency(name, *version_requirements)
-      @target.target_dependencies << Dependency.new(name, *version_requirements)
+    #
+    #
+    # ## Dependency on a library, outside those available in a spec repo.
+    #
+    # ### From a podspec in the root of a library repo.
+    #
+    # Sometimes you may want to use the bleeding edge version of a Pod. Or a
+    # specific revision. If this is the case, you can specify that with your
+    # dependency declaration.
+    #
+    #
+    # To use the `master` branch of the repo:
+    #
+    #   dependency 'TTTFormatterKit', :git => 'https://github.com/gowalla/AFNetworking.git'
+    #
+    #
+    # Or specify a commit:
+    #
+    #   dependency 'TTTFormatterKit', :git => 'https://github.com/gowalla/AFNetworking.git', :commit => '082f8319af'
+    #
+    #
+    # It is important to note, though, that this means that the version will
+    # have to satisfy any other dependencies on the Pod by other Pods.
+    #
+    #
+    # The `podspec` file is expected to be in the root of the repo, if this
+    # library does not have a `podspec` file in its repo yet, you will have to
+    # use one of the approaches outlined in the sections below.
+    #
+    #
+    # ### From a podspec outside a spec repo, for a library without podspec.
+    #
+    # If a podspec is available from another source outside of the library’s
+    # repo. Consider, for instance, a podpsec available via HTTP:
+    #
+    #   dependency 'JSONKit', :podspec => 'https://raw.github.com/gist/1346394/1d26570f68ca27377a27430c65841a0880395d72/JSONKit.podspec'
+    #
+    #
+    # ### For a library without any available podspec
+    #
+    # Finally, if no man alive has created a podspec, for the library you want
+    # to use, yet, you will have to specify the library yourself.
+    #
+    #
+    # When you omit arguments and pass a block to `dependency`, an instance of
+    # Pod::Specification is yielded to the block. This is the same class which
+    # is normally used to specify a Pod.
+    #
+    #   dependency do |spec|
+    #     spec.name         = 'JSONKit'
+    #     spec.version      = '1.4'
+    #     spec.source       = { :git => 'https://github.com/johnezang/JSONKit.git', :tag => 'v1.4' }
+    #     spec.source_files = 'JSONKit.*'
+    #   end
+    #
+    #
+    # For more info on the definition of a Pod::Specification see:
+    # https://github.com/alloy/cocoapods/wiki/A-pod-specification
+    #
+    #
+    def dependency(*name_and_version_requirements, &block)
+      @target.target_dependencies << Dependency.new(*name_and_version_requirements, &block)
     end
 
     def dependencies

spec/unit/dependency_spec.rb

@@ -7,7 +7,21 @@ describe "Pod::Dependency" do
     dep1.merge(dep2).should == Pod::Dependency.new('bananas', '>= 1.8', '1.9')
   end
 
-  it "is equal to another dependency if the `part_of_other_pod' flag is the same" do
+  it "returns wether or not the spec for this pod is in a spec repo" do
+    dep = Pod::Dependency.new('bananas')
+    dep.should.not.be.external_podspec
+    dep.external_spec_source = { :git => 'GIT-URL' }
+    dep.should.be.external_podspec
+  end
+
+  it "returns wether or not the spec for this pod is defined inline" do
+    dep = Pod::Dependency.new { |s| s.name = 'bananas' }
+    dep.should.be.inline_podspec
+    dep.specification.should.be.instance_of Pod::Specification
+    dep.specification.name.should == 'bananas'
+  end
+
+  it "is equal to another dependency if `part_of_other_pod' is the same" do
     dep1 = Pod::Dependency.new('bananas', '>= 1')
     dep1.only_part_of_other_pod = true
     dep2 = Pod::Dependency.new('bananas', '>= 1')
@@ -15,4 +29,20 @@ describe "Pod::Dependency" do
     dep2.only_part_of_other_pod = true
     dep1.should == dep2
   end
+
+  it "is equal to another dependency if `external_spec_source' is the same" do
+    dep1 = Pod::Dependency.new('bananas', :git => 'GIT-URL')
+    dep2 = Pod::Dependency.new('bananas')
+    dep1.should.not == dep2
+    dep2.external_spec_source = { :git => 'GIT-URL' }
+    dep1.should == dep2
+  end
+
+  it "is equal to another dependency if `specification' is equal" do
+    dep1 = Pod::Dependency.new { |s| s.name = 'bananas'; s.version = '1' }
+    dep2 = Pod::Dependency.new('bananas')
+    dep1.should.not == dep2
+    dep2 = Pod::Dependency.new { |s| s.name = 'bananas'; s.version = '1' }
+    dep1.should == dep2
+  end
 end

spec/unit/podfile_spec.rb

@@ -18,6 +18,35 @@ describe "Pod::Podfile" do
     podfile.dependency_by_name('SSZipArchive').should == Pod::Dependency.new('SSZipArchive', '>= 0.1')
   end
 
+  it "adds a dependency on a Pod repo outside of a spec repo (the repo is expected to contain a podspec)" do
+    podfile = Pod::Podfile.new do
+      dependency 'SomeExternalPod', :git => 'GIT-URL', :commit => '1234'
+    end
+    dep = podfile.dependency_by_name('SomeExternalPod')
+    dep.should.be.external_podspec
+    dep.external_spec_source.should == { :git => 'GIT-URL', :commit => '1234' }
+  end
+
+  it "adds a dependency on a library outside of a spec repo (the repo does not need to contain a podspec)" do
+    podfile = Pod::Podfile.new do
+      dependency 'SomeExternalPod', :podspec => 'http://gist/SomeExternalPod.podspec'
+    end
+    dep = podfile.dependency_by_name('SomeExternalPod')
+    dep.should.be.external_podspec
+    dep.external_spec_source.should == { :podspec => 'http://gist/SomeExternalPod.podspec' }
+  end
+
+  it "adds a dependency on a library by specifying the podspec inline" do
+    podfile = Pod::Podfile.new do
+      dependency do |s|
+        s.name = 'SomeExternalPod'
+      end
+    end
+    dep = podfile.dependency_by_name('SomeExternalPod')
+    dep.should.be.inline_podspec
+    dep.specification.name.should == 'SomeExternalPod'
+  end
+
   it "specifies that BridgeSupport metadata should be generated" do
     Pod::Podfile.new {}.should.not.generate_bridge_support
     Pod::Podfile.new { generate_bridge_support! }.should.generate_bridge_support