#363 - Apply shim to RDFTurtle for long literals regex

Author: Marco De Salvo

RDFSharp/Model/RDFModelShims.cs

@@ -27,6 +27,7 @@ public static partial class RDFModelShims
         internal const string PrefixRegexMask = @"^[a-zA-Z0-9_\-]+$";
         internal const string SubLanguageTagRegexMask = "(-[a-zA-Z0-9]{1,8})*(--ltr|--rtl)?";
         internal const string LanguageTagRegexMask = "[a-zA-Z]{1,8}" + SubLanguageTagRegexMask;
+        internal const string TurtleLongLiteralCharsRegexMask = "[\n\r\t\"]";
         #endregion
 
         #region Ctors
@@ -35,9 +36,11 @@ static RDFModelShims()
 #if NET8_0_OR_GREATER
             PrefixRegexShim = PrefixRegex();
             LanguageTagRegexShim = LanguageTagRegex();
+            TurtleLongLiteralCharsRegexShim = TurtleLongLiteralCharsRegex();
 #else
             PrefixRegexShim = new Regex(PrefixRegexMask, RegexOptions.Compiled);
             LanguageTagRegexShim = new Regex("^" + LanguageTagRegexMask + "$", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+            TurtleLongLiteralCharsRegexShim = new Regex(TurtleLongLiteralCharsRegexMask, RegexOptions.Compiled);
 #endif
         }
         #endregion
@@ -46,6 +49,8 @@ static RDFModelShims()
         internal static Regex PrefixRegexShim { get; }
 
         internal static Regex LanguageTagRegexShim { get; }
+
+        internal static Regex TurtleLongLiteralCharsRegexShim { get; }
         #endregion
 
 #if NET8_0_OR_GREATER
@@ -54,6 +59,9 @@ static RDFModelShims()
 
         [GeneratedRegex("^" + LanguageTagRegexMask + "$", RegexOptions.IgnoreCase)]
         private static partial Regex LanguageTagRegex();
+
+        [GeneratedRegex(TurtleLongLiteralCharsRegexMask)]
+        private static partial Regex TurtleLongLiteralCharsRegex();
 #endif
     }
 }

RDFSharp/Model/Serializers/RDFTurtle.cs

@@ -20,7 +20,6 @@ limitations under the License.
 using System.IO;
 using System.Linq;
 using System.Text;
-using System.Text.RegularExpressions;
 using RDFSharp.Query;
 
 namespace RDFSharp.Model
@@ -30,13 +29,6 @@ namespace RDFSharp.Model
     /// </summary>
     internal static class RDFTurtle
     {
-        #region Properties
-        /// <summary>
-        /// Regex to catch literals which must be escaped as long literals in Turtle
-        /// </summary>
-        internal static readonly Lazy<Regex> regexTTL = new Lazy<Regex>(() => new Regex("[\n\r\t\"]", RegexOptions.Compiled));
-        #endregion
-
         #region Methods
 
         #region Write
@@ -1618,7 +1610,7 @@ orderby triple.Subject.ToString(), triple.Predicate.ToString()
                     {
                         //Detect presence of long-literals in order to write proper delimiter
                         string litValDelim = "\"";
-                        if (regexTTL.Value.Match(triple.Object.ToString()).Success)
+                        if (RDFModelShims.TurtleLongLiteralCharsRegexShim.Match(triple.Object.ToString()).Success)
                             litValDelim = "\"\"\"";
 
                         //Write the literal's Turtle token