move capturing to its own extension

lib/sinatra/capture.rb

@@ -0,0 +1,46 @@
+require 'sinatra/base'
+
+module Sinatra
+  module Capture
+    DUMMIES = {
+      Tilt::HamlTemplate   => "!= capture_haml(*args, &block)",
+      Tilt::ERBTemplate    => "<% yield(*args) %>",
+      Tilt::ErubisTemplate => "<%= yield(*args) %>",
+      :slim                => "== yield(*args)"
+    }
+
+    def call!(env)
+      @current_engine = :ruby
+      super
+    end
+
+    def capture(options = {}, &block)
+      opts   = { :block  => block, :args => [] }.merge options
+      engine = opts.delete(:engine)  || @current_engine
+      block  = opts[:block]
+      if engine == :ruby
+        block[*opts[:args]]
+      else
+        dummy = DUMMIES[Tilt[engine]] || DUMMIES.fetch(engine)
+        eval '_buf.clear if defined? _buf', block.binding
+        render(engine, dummy, {}, opts, &block)
+      end
+    end
+
+    def capture_later(options = {}, &block)
+      opts = { :block => block, :args => [], :engine => @current_engine }
+      opts.merge options
+    end
+
+    private
+
+    def render(engine, *)
+      @current_engine, engine_was = engine.to_sym, @current_engine
+      super
+    ensure
+      @current_engine = engine_was
+    end
+  end
+
+  helpers Capture
+end

lib/sinatra/content_for.rb

@@ -1,4 +1,5 @@
 require 'sinatra/base'
+require 'sinatra/capture'
 
 module Sinatra
   ##
@@ -36,6 +37,8 @@ module Sinatra
   # <tt>content_for</tt> setting the appropriate set of tags that should
   # be added to the layout.
   module ContentFor
+    include Capture
+
     # Capture a block of content to be rendered later. For example:
     #
     #     <% content_for :head do %>
@@ -50,8 +53,7 @@ module ContentFor
     # Your blocks can also receive values, which are passed to them
     # by <tt>yield_content</tt>
     def content_for(key, &block)
-      @current_engine ||= :ruby
-      content_blocks[key.to_sym] << [@current_engine, block]
+      content_blocks[key.to_sym] << capture_later(&block)
     end
 
     # Render the captured blocks for a given key. For example:
@@ -72,33 +74,12 @@ def content_for(key, &block)
     # Would pass <tt>1</tt> and <tt>2</tt> to all the blocks registered
     # for <tt>:head</tt>.
     def yield_content(key, *args)
-      content_blocks[key.to_sym].map { |e,b| capture(e, args, b) }.join
-    end
-
-    def self.capture
-      @capture ||= {}
+      opts = { :args => args }
+      content_blocks[key.to_sym].map { |c| capture c.merge(opts) }.join
     end
 
     private
 
-    # generated templates will be cached by Sinatra in production
-    capture[:haml]   = "!= capture_haml(*args, &block)"
-    capture[:erb]    = "<% yield(*args) %>"
-    capture[:erubis] = "<%= yield(*args) %>"
-    capture[:slim]   = "== yield(*args)"
-
-    def capture(engine, args, block)
-      eval '_buf.clear if defined? _buf', block.binding
-      render(engine, Sinatra::ContentFor.capture.fetch(engine), {}, :args => args, :block => block, &block)
-    end
-
-    def render(engine, *)
-      @current_engine, engine_was = engine.to_sym, @current_engine
-      super
-    ensure
-      @current_engine = engine_was
-    end
-
     def content_blocks
       @content_blocks ||= Hash.new {|h,k| h[k] = [] }
     end

lib/sinatra/contrib.rb

@@ -11,6 +11,8 @@ module Common
       register :ConfigFile
       register :Namespace
       register :RespondWith
+
+      helpers :Capture
       helpers :ContentFor
       helpers :LinkHeader
     end

sinatra-contrib.gemspec

@@ -28,6 +28,7 @@ Gem::Specification.new do |s|
     "README.md",
     "Rakefile",
     "ideas.md",
+    "lib/sinatra/capture.rb",
     "lib/sinatra/config_file.rb",
     "lib/sinatra/content_for.rb",
     "lib/sinatra/contrib.rb",