Initial github import of liquid

lib/liquid/block.rb

@@ -0,0 +1,98 @@
+module Liquid
+  
+  class Block < Tag
+
+    def parse(tokens)
+      @nodelist ||= []
+      @nodelist.clear
+
+      while token = tokens.shift 
+
+        case token
+        when /^#{TagStart}/                   
+          if token =~ /^#{TagStart}\s*(\w+)\s*(.*)?#{TagEnd}$/
+
+            # if we found the proper block delimitor just end parsing here and let the outer block
+            # proceed                               
+            if block_delimiter == $1
+              end_tag
+              return
+            end
+
+            # fetch the tag from registered blocks
+            if tag = Template.tags[$1]
+              @nodelist << tag.new($1, $2, tokens)
+            else
+              # this tag is not registered with the system 
+              # pass it to the current block for special handling or error reporting
+              unknown_tag($1, $2, tokens)
+            end              
+          else
+            raise SyntaxError, "Tag '#{token}' was not properly terminated with regexp: #{TagEnd.inspect} "
+          end
+        when /^#{VariableStart}/
+          @nodelist << create_variable(token)
+        when ''
+          # pass
+        else
+          @nodelist << token
+        end
+      end       
+      
+      # Make sure that its ok to end parsing in the current block. 
+      # Effectively this method will throw and exception unless the current block is 
+      # of type Document 
+      assert_missing_delimitation!
+    end                     
+    
+    def end_tag      
+    end
+
+    def unknown_tag(tag, params, tokens)
+      case tag 
+      when 'else'
+        raise SyntaxError, "#{block_name} tag does not expect else tag"
+      when 'end'
+        raise SyntaxError, "'end' is not a valid delimiter for #{block_name} tags. use #{block_delimiter}"
+      else
+        raise SyntaxError, "Unknown tag '#{tag}'"
+      end
+    end
+
+    def block_delimiter
+      "end#{block_name}"
+    end                           
+
+    def block_name
+      @tag_name
+    end
+
+    def create_variable(token)
+      token.scan(/^#{VariableStart}(.*)#{VariableEnd}$/) do |content|
+        return Variable.new(content.first)
+      end
+      raise SyntaxError.new("Variable '#{token}' was not properly terminated with regexp: #{VariableEnd.inspect} ")
+    end
+
+    def render(context)
+      render_all(@nodelist, context)
+    end
+    
+    protected
+
+    def assert_missing_delimitation!
+      raise SyntaxError.new("#{block_name} tag was never closed")
+    end
+
+    def render_all(list, context)
+      list.collect do |token|
+        begin        
+          token.respond_to?(:render) ? token.render(context) : token
+        rescue Exception => e          
+          context.handle_error(e)
+        end
+          
+      end      
+    end
+  end  
+end