CCL writer shall write only id and type chunk attrs (if non-empty), in compliance with DTD

CMakeLists.txt

@@ -2,7 +2,7 @@ PROJECT(Corpus2Library)
 
 set(corpus2_ver_major "1")
 set(corpus2_ver_minor "2")
-set(corpus2_ver_patch "0")
+set(corpus2_ver_patch "1")
 
 cmake_minimum_required(VERSION 2.8.0)
 

libcorpus2/io/cclwriter.cpp

@@ -127,9 +127,20 @@ void CclWriter::paragraph_head()
 
 void CclWriter::paragraph_head(const Chunk& c)
 {
+	// in CCL format chunks may have at most two attributes:
+	// id (unique XML-style id) and type (typically p for paragraphs)
 	osi() << "<chunk";
-	BOOST_FOREACH(const Chunk::attr_map_t::value_type& v, c.attributes()) {
-		os() << " " << v.first << "=\"" << v.second << "\"";
+	if (c.has_attribute("id")) {
+		const std::string &val = c.get_attribute("id");
+		if (!val.empty()) {
+			os() << " id=\"" << val << "\"";
+		}
+	}
+	if (c.has_attribute("type")) {
+		const std::string &val = c.get_attribute("type");
+		if (!val.empty()) {
+			os() << " type=\"" << val << "\"";
+		}
 	}
 	os() << ">\n";
 }

libcorpus2/io/writer.h

@@ -151,6 +151,10 @@ protected:
 		return indent_;
 	}
 
+	/**
+	 * Write indentation spaces to the output stream and return the stream
+	 * for writing. Convenience function useful when starting new lines
+	 * in the output. */
 	std::ostream& osi();
 
 private: