Allow nested interpolations

README.textile

@@ -43,6 +43,13 @@ You may also specify options for @link_to@. Just give a second option named like
 You may pass any kind of object accepted by @link_to@ as the link target, so your loved named routes like
 @article_path(:id => article.id)@ or hashes like @{controller: "articles", action: "index"}@ will all work fine, too.
 
+Even nested interpolations are possible:
+
+<pre><code>en:
+  copy: "Did you read this %{link:nice %{guide}}?"</code></pre>
+
+<pre><code><%=t_link "copy", link: "http://guides.rubyonrails.org/i18n.html", guide: 'article' %></code></pre>
+
 h2. isit18.com?
 
 Sorry, I'm using Ruby 1.9.2 at the time of writing and didn't took the time to port i18n_link back to Ruby 1.8. You either might update to Ruby 1.9 as well

lib/i18n_link/helper.rb

@@ -7,22 +7,37 @@ module Helper
 
     def t_link(translation, options = {})
       options.symbolize_keys!
-      string = h(t(translation)).gsub(/%\{[^}]+\}/) do |tl|
+      string = String.new(h(t(translation))) # We want an escaped String, not an ActiveSupport::SafeBuffer
+
+      # Resolve the inner interpolations of nested interpolations
+      string.gsub!(/(%\{[^}]+:[^}]*)(%\{[^}]+\})([^}]*\})/) do |tl|
+        token = $2[2..-2].to_sym
+        if options.has_key?(token)
+          "#{$1}#{options[token]}#{$3}"
+        else
+          tl
+        end
+      end
+
+      # Parse links
+      string.gsub!(/%\{[^}]+\}/) do |tl|
         if tl.include?(":")
           token, label = tl[2..-2].split(":", 2)
           addr = options.delete(token.to_sym)
           if addr.nil?
             tl
           else
             link_options = options.delete("#{token}_options".to_sym)
-            link_to(label, addr, link_options)
+            link_to(raw(label), addr, link_options)
           end
         else
           tl
         end
       end
+
+      # Escape HTML of the replacements and interpolate
       options.each { |key, value| options[key] = (value.is_a?(String) && !value.html_safe?) ? h(value) : value }
       raw(string % options)
     end
   end
-end
+end

spec/i18n_link_helper_spec.rb

@@ -62,4 +62,9 @@
     I18n.backend.store_translations(:en, :test5 => "Hello %{name}.")
     @view.t_link("test5", :name => '<a href="http://www.rubyonrails.org">Rails</a>'.html_safe).should == 'Hello <a href="http://www.rubyonrails.org">Rails</a>.'
   end
-end
+
+  it "should allow interpolations inside of links" do
+    I18n.backend.store_translations(:en, :test6 => "Did you read our %{link:nice %{article}}?")
+    @view.t_link("test6", :link => "/article/2", :article => "article").should == 'Did you read our <a href="/article/2">nice article</a>?'
+  end
+end