fix iob-chan reader: dont complain when no channels at all

CMakeLists.txt

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

libcorpus2/io/iob-chan.cpp

@@ -145,13 +145,14 @@ Sentence::Ptr IobChanReader::actual_next_sentence()
 		}
 		std::vector<std::string> spl;
 		boost::algorithm::split(spl, line, boost::is_any_of("\t"));
-		if (spl.size() != 4) {
+		if (spl.size() != 3 and spl.size() != 4) {
 			std::cerr << "Invalid line: " << line << "(" << spl.size() << ")\n";
 		} else {
 			const std::string& orth = spl[0];
 			const std::string& lemma = spl[1];
 			const std::string& tag_string = spl[2];
-			const std::string& anns = spl[3];
+			// if no annotations, let anns = ""
+			const std::string& anns = (spl.size() == 4) ? spl[3] : "";
 			Tag tag = parse_tag(tag_string);
 			Token* t = new Token();
 			t->set_orth(UnicodeString::fromUTF8(orth));
@@ -165,6 +166,7 @@ Sentence::Ptr IobChanReader::actual_next_sentence()
 				t->set_wa(PwrNlp::Whitespace::Newline);
 			}
 			s->append(t);
+			if (!anns.empty()) {
 				std::vector<std::string> annsplit;
 				boost::algorithm::split(annsplit, anns, boost::is_any_of(","));
 				foreach (const std::string& a, annsplit) {
@@ -188,6 +190,7 @@ Sentence::Ptr IobChanReader::actual_next_sentence()
 				}
 			}
 		}
+	}
 	if (s) {
 		foreach (const AnnotatedSentence::chan_map_t::value_type& v, s->all_channels()) {
 			s->get_channel(v.first).make_segments_from_iob();