adding stats to the layout with file_exists plugin

_layouts/postag.html

@@ -6,6 +6,16 @@ <h2><code>{{ page.title }}</code>: {{ page.shortdef }}</h2>
 
 {{ content }}
 
+
+<!-- "automatic stats" -->
+{% capture langdir %}{{ page.path | split:"/" | first | split:"-" | first | replace_first:'_',''}}{% endcapture %}
+{% capture statspath %}stats/{{langdir}}/{{page.title}}.md{% endcapture %}
+{% capture statsexist %}{% file_exists _includes/{{statspath}} %}{% endcapture %}
+{% if statsexist  == "true" %}
+{% capture statsinclude %}{% include {{statspath}} %}{% endcapture %}
+{{ statsinclude | markdownify }}
+{% endif %}
+
 <!-- "in other languages" links -->
 <hr/>
 {% for r in site.data.postags %}{% if r.label == page.title %}

_plugins/file_exists.rb

@@ -0,0 +1,20 @@
+module Jekyll
+    class FileExistsTag < Liquid::Tag
+
+        def initialize(tag_name, path, tokens)
+            super
+            @path = path
+        end
+
+        def render(context)
+            # ref https://gist.github.com/vanto/1455726
+            # pipe param through liquid to make additional replacements possible
+            url = Liquid::Template.parse(@path).render context
+
+            # check if file exists (returns true or false)
+            "#{File.exist?(url.strip!)}"
+        end
+    end
+end
+
+Liquid::Template.register_tag('file_exists', Jekyll::FileExistsTag)