diff --git a/bin/cm b/bin/cm
index 8cc463e29..04546d68b 100755
--- a/bin/cm
+++ b/bin/cm
@@ -14,6 +14,11 @@ desc 'Generate HTML documentation'
 long_desc 'Generate HTML docs from a Docurium config file'
 command :doc do |c|
   c.flag :for, :desc => "The version to generate", :multiple => true
+  c.switch [:n, "dry-run"], :desc => "Dry-run"
+  c.switch [:d, "debug"], :desc => "Enable debug log"
+  c.flag "debug-file", :desc => "Enable debug output for header", :multiple => true
+  c.flag "debug-function", :desc => "Show debug output when processing function", :multiple => true
+  c.flag "debug-type", :desc => "Show debug output when processing type", :multiple => true
   c.action do |global_options,options,args|
     file = args.first
     Docurium::CLI.doc(file, options)
diff --git a/lib/docurium.rb b/lib/docurium.rb
index a6932cd0e..300e1fb60 100644
--- a/lib/docurium.rb
+++ b/lib/docurium.rb
@@ -4,6 +4,7 @@
 require 'rocco'
 require 'docurium/version'
 require 'docurium/layout'
+require 'docurium/debug'
 require 'libdetect'
 require 'docurium/docparser'
 require 'pp'
@@ -19,12 +20,13 @@
 class Docurium
   attr_accessor :branch, :output_dir, :data, :head_data
 
-  def initialize(config_file, repo = nil)
+  def initialize(config_file, cli_options = {}, repo = nil)
     raise "You need to specify a config file" if !config_file
     raise "You need to specify a valid config file" if !valid_config(config_file)
     @sigs = {}
     @head_data = nil
     @repo = repo || Rugged::Repository.discover(config_file)
+    @cli_options = cli_options
   end
 
   def init_data(version = 'HEAD')
@@ -192,9 +194,11 @@ def generate_docs(options)
 
       print "Generating documentation [#{i}/#{versions.count}]\r"
 
-      output_index.add(:path => "#{version}.json", :oid => sha, :mode => 0100644)
-      examples.each do |path, id|
-        output_index.add(:path => path, :oid => id, :mode => 0100644)
+      unless dry_run?
+        output_index.add(:path => "#{version}.json", :oid => sha, :mode => 0100644)
+        examples.each do |path, id|
+          output_index.add(:path => path, :oid => id, :mode => 0100644)
+        end
       end
     end
 
@@ -203,6 +207,8 @@ def generate_docs(options)
       show_warnings(head_data)
     end
 
+    return if dry_run?
+
     # We tally the signatures in the order they finished, which is
     # arbitrary due to the concurrency, so we need to sort them once
     # they've finished.
@@ -391,7 +397,7 @@ def parse_headers(index, version)
     data = init_data(version)
     DocParser.with_files(files, :prefix => version) do |parser|
       headers.each do |header|
-        records = parser.parse_file(header)
+        records = parser.parse_file(header, debug: interesting?(:file, header))
         update_globals!(data, records)
       end
     end
@@ -466,16 +472,20 @@ def valid_config(file)
   def group_functions!(data)
     func = {}
     data[:functions].each_pair do |key, value|
+      debug_set interesting?(:function, key)
+      debug "grouping #{key}: #{value}"
       if @options['prefix']
         k = key.gsub(@options['prefix'], '')
       else
         k = key
       end
       group, rest = k.split('_', 2)
+      debug "grouped: k: #{k}, group: #{group}, rest: #{rest}"
       if group.empty?
         puts "empty group for function #{key}"
         next
       end
+      debug "grouped: k: #{k}, group: #{group}, rest: #{rest}"
       data[:functions][key][:group] = group
       func[group] ||= []
       func[group] << key
@@ -521,6 +531,25 @@ def update_globals!(data, recs)
     md = Redcarpet::Markdown.new(Redcarpet::Render::HTML.new({}), :no_intra_emphasis => true)
     recs.each do |r|
 
+      types = %w(function file type).map(&:to_sym)
+      dbg = false
+      types.each do |t|
+        dbg ||= if r[:type] == t and interesting?(t, r[:name])
+          true
+        elsif t == :file and interesting?(:file, r[:file])
+          true
+        elsif [:struct, :enum].include?(r[:type]) and interesting?(:type, r[:name])
+          true
+        else
+          false
+        end
+      end
+
+      debug_set dbg
+
+      debug "processing record: #{r}"
+      debug
+
       # initialize filemap for this file
       file_map[r[:file]] ||= {
         :file => r[:file], :functions => [], :meta => {}, :lines => 0
@@ -628,6 +657,10 @@ def update_globals!(data, recs)
         # Anything else we want to record?
       end
 
+      debug "processed record: #{r}"
+      debug
+
+      debug_restore
     end
 
     data[:files] << file_map.values[0]
@@ -658,4 +691,12 @@ def write_site(index)
   def out(text)
     puts text
   end
+
+  def dry_run?
+    @cli_options[:dry_run]
+  end
+
+  def interesting?(type, what)
+    @cli_options['debug'] || (@cli_options["debug-#{type}"] || []).include?(what)
+  end
 end
diff --git a/lib/docurium/cli.rb b/lib/docurium/cli.rb
index 13f209642..d22c36cd2 100644
--- a/lib/docurium/cli.rb
+++ b/lib/docurium/cli.rb
@@ -2,8 +2,8 @@ class Docurium
   class CLI
 
     def self.doc(idir, options)
-      doc = Docurium.new(idir)
-      doc.generate_docs(options)
+      doc = Docurium.new(idir, options)
+      doc.generate_docs
     end
 
     def self.check(idir, options)
diff --git a/lib/docurium/debug.rb b/lib/docurium/debug.rb
new file mode 100644
index 000000000..da3704891
--- /dev/null
+++ b/lib/docurium/debug.rb
@@ -0,0 +1,41 @@
+$debug_stack = [false]
+
+def debug_enabled
+  $debug_stack[-1]
+end
+
+def debug(str = nil)
+  puts str if debug_enabled
+end
+
+def debug_enable
+  $debug_stack.push true
+end
+
+def debug_silence
+  $debug_stack.push false
+end
+
+def debug_set val
+  $debug_stack.push val
+end
+
+def debug_pass
+  $debug_stack.push debug_enabled
+end
+
+def debug_restore
+  $debug_stack.pop
+end
+
+def with_debug(&block)
+  debug_enable
+  block.call
+  debug_restore
+end
+
+def without_debug(&block)
+  debug_silence
+  block.call
+  debug_restore
+end
\ No newline at end of file
diff --git a/lib/docurium/docparser.rb b/lib/docurium/docparser.rb
index f161b5d44..29edf05cb 100644
--- a/lib/docurium/docparser.rb
+++ b/lib/docurium/docparser.rb
@@ -59,12 +59,14 @@ def cleanup!
 
     # Entry point for this parser
     # Parse `filename` out of the hash `files`
-    def parse_file(orig_filename)
+    def parse_file(orig_filename, opts = {})
 
       includes = find_clang_includes + [@tmpdir]
 
       # Override the path we want to filter by
       filename = File.join(@tmpdir, orig_filename)
+      debug_enable if opts[:debug]
+      debug "parsing #{filename} #{@tmpdir}"
       args = includes.map { |path| "-I#{path}" }
       args << '-ferror-limit=1'
 
@@ -73,12 +75,13 @@ def parse_file(orig_filename)
       recs = []
 
       tu.cursor.visit_children do |cursor, parent|
-        #puts "visiting #{cursor.kind} - #{cursor.spelling}"
         location = cursor.location
         next :continue if location.file == nil
         next :continue unless location.file == filename
 
-        #puts "for file #{location.file} #{cursor.kind} #{cursor.spelling} #{cursor.comment.kind} #{location.line}"
+        loc = "%d:%d-%d:%d" % [cursor.extent.start.line, cursor.extent.start.column, cursor.extent.end.line, cursor.extent.end.column]
+        debug "#{cursor.location.file}:#{loc} - visiting #{cursor.kind}: #{cursor.spelling}, comment is #{cursor.comment.kind}"
+
         #cursor.visit_children do |c|
         #  puts "  child #{c.kind}, #{c.spelling}, #{c.comment.kind}"
         #  :continue
@@ -95,25 +98,38 @@ def parse_file(orig_filename)
           :tdef => nil,
         }
 
-        case cursor.kind
+        extract = case cursor.kind
         when :cursor_function
-          #puts "have function"
-          rec.merge! extract_function(cursor)
+          debug "have function #{cursor.spelling}"
+          rec.update extract_function(cursor)
         when :cursor_enum_decl
-          rec.merge! extract_enum(cursor)
+          debug "have enum #{cursor.spelling}"
+          rec.update extract_enum(cursor)
         when :cursor_struct
-          #puts "raw struct"
-          rec.merge! extract_struct(cursor)
+          debug "have struct #{cursor.spelling}"
+          rec.update extract_struct(cursor)
         when :cursor_typedef_decl
-          rec.merge! extract_typedef(cursor)
+          debug "have typedef #{cursor.spelling} #{cursor.underlying_type.spelling}"
+          rec.update extract_typedef(cursor)
         else
           raise "No idea how to deal with #{cursor.kind}"
         end
 
+        rec.merge! extract
+
         recs << rec
         :continue
       end
 
+      if debug_enabled
+        puts "parse_file: parsed #{recs.size} records for #{filename}:"
+        recs.each do |r|
+          puts "\t#{r}"
+        end
+      end
+
+      debug_restore
+
       recs
     end
 
@@ -187,15 +203,27 @@ def extract_function_args(cursor, cmt)
 
     def extract_subject_desc(comment)
       subject = comment.child.text
+      debug "\t\tsubject: #{subject}"
       paras = comment.find_all { |cmt| cmt.kind == :comment_paragraph }.drop(1).map { |p| p.text }
       desc = paras.join("\n\n")
+      debug "\t\tdesc: #{desc}"
       return subject, desc
     end
 
     def extract_function(cursor)
       comment = cursor.comment
 
-      #puts "looking at function #{cursor.spelling}, #{cursor.display_name}"
+      $buggy_functions = %w()
+      debug_set ($buggy_functions.include? cursor.spelling)
+      if debug_enabled
+        puts "\tlooking at function #{cursor.spelling}, #{cursor.display_name}"
+        puts "\tcomment: #{comment}, #{comment.kind}"
+        cursor.visit_children do |cur, parent|
+          puts "\t\tchild: #{cur.spelling}, #{cur.kind}"
+          :continue
+        end
+      end
+
       cmt = extract_function_comment(comment)
       args = extract_function_args(cursor, cmt)
       #args = args.reject { |arg| arg[:comment].nil? }
@@ -220,6 +248,7 @@ def extract_function(cursor)
       decl = "#{ret[:type]} #{cursor.spelling}(#{argline})"
       body = "#{decl};"
 
+      debug_restore
       #puts cursor.display_name
       # Return the format that docurium expects
       {
@@ -238,6 +267,7 @@ def extract_function(cursor)
 
     def extract_function_comment(comment)
       subject, desc = extract_subject_desc(comment)
+      debug "\t\textract_function_comment: #{comment}, #{comment.kind}, #{subject}, #{desc}"
 
       args = {}
       (comment.find_all { |cmt| cmt.kind == :comment_param_command }).each do |param|
@@ -313,7 +343,7 @@ def extract_struct(cursor)
         :continue
       end
 
-      #puts "struct value #{values}"
+      debug "\tstruct value #{values}"
 
       rec = {
         :type => :struct,
diff --git a/test/docurium_test.rb b/test/docurium_test.rb
index 48f48ed36..0cf1ed054 100644
--- a/test/docurium_test.rb
+++ b/test/docurium_test.rb
@@ -20,7 +20,7 @@ def setup
     end
 
     @path = File.dirname(__FILE__) + '/fixtures/git2/api.docurium'
-    @doc = Docurium.new(@path, @repo)
+    @doc = Docurium.new(@path, {}, @repo)
     @data = @doc.parse_headers(index, 'HEAD')
   end