Merge pull request #1495 from maul-esel/variable-include

Variable {% include %}

features/include_tag.feature

@@ -33,3 +33,16 @@ Feature: Include tags
     And I should see "<li>param1_or_2 = value</li>" in "_site/2013/04/12/parameter-syntax.html"
     And I should see "<li>local = some text</li>" in "_site/2013/06/22/pass-a-variable.html"
     And I should see "<li>layout = default</li>" in "_site/2013/06/22/pass-a-variable.html"
+
+  Scenario: Include a file from a variable
+    Given I have an _includes directory
+    And I have an "_includes/snippet.html" file that contains "a snippet"
+    And I have an "_includes/parametrized.html" file that contains "works with {{include.what}}"
+    And I have a configuration file with:
+    | key           | value             |
+    | include_file1 | snippet.html      |
+    | include_file2 | parametrized.html |
+    And I have an "index.html" page that contains "{% include {{site.include_file1}} %} that {% include {{site.include_file2}} what='parameters' %}"
+    When I run jekyll
+    Then the _site directory should exist
+    And I should see "a snippet that works with parameters" in "_site/index.html"

lib/jekyll/tags/include.rb

@@ -84,10 +84,18 @@ eos
         context.registers[:site].file_read_opts
       end
 
+      def retrieve_variable(context)
+        if /\{\{([\w\-\.]+)\}\}/ =~ @file
+          raise ArgumentError.new("No variable #{$1} was found in include tag") if context[$1].nil?
+          @file = context[$1]
+        end
+      end
+
       def render(context)
         dir = File.join(context.registers[:site].source, INCLUDES_DIR)
         validate_dir(dir, context.registers[:site].safe)
 
+        retrieve_variable(context)
         file = File.join(dir, @file)
         validate_file(file, context.registers[:site].safe)
 

site/docs/templates.md

@@ -192,6 +192,19 @@ Jekyll expects all include files to be placed in an `_includes` directory at the
 root of your source directory. This will embed the contents of
 `<source>/_includes/footer.html` into the calling file.
 
+<div class="note">
+  <h5>ProTip™: Use variables as file name</h5>
+  <p>
+
+    The name of the file you wish to embed can be literal (as in the example above),
+    or you can use a variable, using liquid-like variable syntax as in
+    <code>{% raw %}{% include {{my_variable}} %}{% endraw %}</code>.
+
+    Note that unlike usual liquid variable syntax, you cannot have spaces inside the curly braces.
+
+  </p>
+</div>
+
 You can also pass parameters to an include:
 
 {% highlight ruby %}