1 files changed, 68 insertions, 0 deletions
diff --git a/guides/rails_guides/indexer.rb b/guides/rails_guides/indexer.rb
new file mode 100644
index 0000000000..89fbccbb1d
--- /dev/null
+++ b/guides/rails_guides/indexer.rb
@@ -0,0 +1,68 @@
+require 'active_support/core_ext/object/blank'
+require 'active_support/core_ext/string/inflections'
+
+module RailsGuides
+  class Indexer
+    attr_reader :body, :result, :warnings, :level_hash
+
+    def initialize(body, warnings)
+      @body     = body
+      @result   = @body.dup
+      @warnings = warnings
+    end
+
+    def index
+      @level_hash = process(body)
+    end
+
+    private
+
+    def process(string, current_level=3, counters=[1])
+      s = StringScanner.new(string)
+
+      level_hash = {}
+
+      while !s.eos?
+        re = %r{^h(\d)(?:\((#.*?)\))?\s*\.\s*(.*)$}
+        s.match?(re)
+        if matched = s.matched
+          matched =~ re
+          level, idx, title = $1.to_i, $2, $3.strip
+
+          if level < current_level
+            # This is needed. Go figure.
+            return level_hash
+          elsif level == current_level
+            index = counters.join(".")
+            idx ||= '#' + title_to_idx(title)
+
+            raise "Parsing Fail" unless @result.sub!(matched, "h#{level}(#{idx}). #{index} #{title}")
+
+            key = {
+              :title => title,
+              :id => idx
+            }
+            # Recurse
+            counters << 1
+            level_hash[key] = process(s.post_match, current_level + 1, counters)
+            counters.pop
+
+            # Increment the current level
+            last = counters.pop
+            counters << last + 1
+          end
+        end
+        s.getch
+      end
+      level_hash
+    end
+
+    def title_to_idx(title)
+      idx = title.strip.parameterize.sub(/^\d+/, '')
+      if warnings && idx.blank?
+        puts "BLANK ID: please put an explicit ID for section #{title}, as in h5(#my-id)"
+      end
+      idx
+    end
+  end
+end