diff --git a/lib/anystyle/document.rb b/lib/anystyle/document.rb
index 3b01960..cf27fa6 100644
--- a/lib/anystyle/document.rb
+++ b/lib/anystyle/document.rb
@@ -4,13 +4,15 @@ class << self
       include PdfUtils
 
       def parse(string, delimiter: /\n/, tagged: false)
+        current_label = nil
         new(string.split(delimiter).map { |line|
           label, line = line.split(/\s*:/, 2) if tagged
-          Wapiti::Token.new line, label: label.to_s
+          current_label = label || current_label
+          Wapiti::Token.new line, label: current_label.to_s
         })
       end
 
-      def open(path, format: File.extname(path), tagged: false)
+      def open(path, format: File.extname(path), tagged: false, **options)
         raise ArgumentError,
           "cannot open tainted path: '#{path}'" if path.tainted?
         raise ArgumentError,
@@ -20,8 +22,8 @@ def open(path, format: File.extname(path), tagged: false)
 
         case format.downcase
         when '.pdf'
-          meta = pdf_meta path
-          info = pdf_info path
+          meta = pdf_meta path if options[:parse_meta]
+          info = pdf_info path if options[:parse_info]
           input = pdf_to_text path
         when '.ttx'
           tagged = true
diff --git a/lib/anystyle/finder.rb b/lib/anystyle/finder.rb
index 6015bc8..7efa0b5 100644
--- a/lib/anystyle/finder.rb
+++ b/lib/anystyle/finder.rb
@@ -15,5 +15,15 @@ class Finder < ParserCore
     def initialize(options = {})
       super(options)
     end
+
+    def expand(dataset)
+      dataset.each do |doc|
+        doc.each_with_index do |(line, page, pn), ln|
+          line.observations = features.map { |f|
+            f.observe line.value, page: page, doc: doc, pn: pn, ln: ln
+          }
+        end
+      end
+    end
   end
 end
diff --git a/lib/anystyle/parser.rb b/lib/anystyle/parser.rb
index 501a822..9a57f4d 100644
--- a/lib/anystyle/parser.rb
+++ b/lib/anystyle/parser.rb
@@ -69,14 +69,7 @@ def normalize(item)
     end
 
     def expand(dataset)
-      dataset.each do |seq|
-        seq.tokens.each_with_index do |tok, idx|
-          alpha = scrub tok.value
-          tok.observations = features.map { |f|
-            f.observe tok.value, alpha, idx, seq
-          }
-        end
-      end
+      raise NotImplementedError
     end
 
     def prepare(input, **opts)
@@ -86,6 +79,8 @@ def prepare(input, **opts)
       case input
       when Wapiti::Dataset
         expand input
+      when Wapiti::Sequence
+        expand Wapiti::Dataset.new([input])
       when String
         if !input.tainted? && input.length < 1024 && File.exists?(input)
           expand Wapiti::Dataset.open(input, opts)
@@ -155,6 +150,21 @@ def initialize(options = {})
       ]
     end
 
+    def expand(dataset)
+      dataset.each do |seq|
+        seq.tokens.each_with_index do |tok, idx|
+          alpha = scrub tok.value
+          tok.observations = features.map { |f|
+            f.observe tok.value, alpha, idx, seq
+          }
+        end
+      end
+    end
+
+    def format_hash(dataset)
+      dataset.map { |seq| normalize(seq.to_h(symbolize_keys: true)) }
+    end
+
     def parse(input, format: options[:format])
       case format
       when :wapiti
@@ -166,10 +176,5 @@ def parse(input, format: options[:format])
         raise ArgumentError, "format not supported: #{format}"
       end
     end
-
-
-    def format_hash(dataset)
-      dataset.map { |seq| normalize(seq.to_h(symbolize_keys: true)) }
-    end
   end
 end