zy/47 fix multiline issue

example/example_7.dart

@@ -0,0 +1,27 @@
+import 'dart:io';
+
+import 'package:rdflib/rdflib.dart';
+
+main() async {
+  String filePath = 'example/sample_ttl_6.ttl';
+  // Read file content to a local String.
+  String fileContents = await File(filePath).readAsStringSync();
+
+  print('-------Original file-------\n$fileContents');
+
+  // Create a graph to read turtle file and store info.
+  Graph g = Graph();
+
+  // Parse with the new method [Graph.parseTurtle] instead of [Graph.parse] (deprecated).
+  g.parseTurtle(fileContents);
+
+  // Serialize the Graph for output.
+  g.serialize(format: 'ttl', abbr: 'short');
+  print('-------Serialized String--------\n${g.serializedString}');
+
+  // Print out full format of triples (will use shorthand in serialization/export).
+  print('--------All triples in the graph-------');
+  for (Triple t in g.triples) {
+    print(t);
+  }
+}

example/sample_ttl_6.ttl

@@ -0,0 +1,14 @@
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix show: <http://example.org/vocab/show/> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+
+show:218 rdfs:label "That Seventies Show"^^xsd:string .            
+show:218 rdfs:label "That Seventies Show"^^<http://www.w3.org/2001/XMLSchema#string> . 
+show:218 rdfs:label "That Seventies Show" .                                           
+show:218 show:localName "That Seventies Show"@en .                 
+show:218 show:localName 'Cette Série des Années Soixante-dix'@fr . 
+show:218 show:localName "Cette Série des Années Septante"@fr-be .  
+show:218 show:blurb '''This is a multi-line
+literal with many quotes (""""")
+and up to two sequential apostrophes ('').'''^^xsd:string .
+

lib/src/graph.dart

@@ -1119,7 +1119,9 @@ class Graph {
   String _preprocessTurtleContent(String turtleContent) {
     // Regular expression to match multiline literals.
 
-    final multilineLiteralRegex = RegExp(r'"""(.*?)"""', dotAll: true);
+    final multilineLiteralRegex = RegExp(
+        turtleContent.contains("'''") ? r"'''(.*?)'''" : r'"""(.*?)"""',
+        dotAll: true);
 
     // Replace each multiline literal with a processed version.
 
@@ -1132,6 +1134,8 @@ class Graph {
       // Example: Replace line breaks with a special sequence.
       String processedLiteral = multilineLiteral.replaceAll('\n', '\\n');
 
+      processedLiteral = processedLiteral.replaceAll('"', '\\"');
+
       // Return the processed literal with the original triple quotes
       return '"$processedLiteral"';
     });

pubspec.yaml

@@ -11,7 +11,7 @@ dependencies:
   http: ^1.2.2
   logging: ^1.2.0
   petitparser: ^6.0.2
-  uuid: ^4.4.2
+  uuid: ^4.4.1
 
 dev_dependencies:
   lints: ^2.0.1