Add Null-coalescing assignation ??=

and Test

Author: codingseb

CodingSeb.ExpressionEvaluator.Tests/ExpressionEvaluatorScriptEvaluateTests.cs

@@ -570,12 +570,23 @@ public static IEnumerable<TestCaseData> TestCasesForScriptEvaluateTests
                 yield return new TestCaseData("x >>= 2;",
                    evaluator0011,
                     new Action(() => evaluator0011.Variables["x"].ShouldBe(5)),
-                    new Action(() => evaluator0011.Variables["x"].ShouldBe(1)), null)
+                    new Action(() => evaluator0011.Variables["x"].ShouldBe(1)),
+                    null)
                 .SetCategory("Script")
                 .SetCategory("Variable assignation")
                 .SetCategory(">>=")
                 .Returns(1);
 
+                yield return new TestCaseData(Resources.Script0071,
+                    null,
+                    null,
+                    null,
+                    null)
+                .SetCategory("Script")
+                .SetCategory("Variable assignation")
+                .SetCategory("??=")
+                .Returns("First Null-coalescing assignation");
+
                 #endregion
 
                 #region Array content assignation

CodingSeb.ExpressionEvaluator.Tests/Resources.Designer.cs

@@ -328,4 +328,7 @@
   <data name="Script0070" type="System.Resources.ResXFileRef, System.Windows.Forms">
     <value>resources\script0070.txt;System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089;utf-8</value>
   </data>
+  <data name="Script0071" type="System.Resources.ResXFileRef, System.Windows.Forms">
+    <value>resources\script0071.txt;System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089;utf-8</value>
+  </data>
 </root>

CodingSeb.ExpressionEvaluator.Tests/Resources.resx

@@ -0,0 +1,7 @@
+/* Script0071 */
+var myVar = null;
+
+myVar ??= "First Null-coalescing assignation";
+myVar ??= "Second Null-coalescing assignation";
+
+return myVar;

CodingSeb.ExpressionEvaluator.Tests/Resources/Script0071.txt

@@ -30,7 +30,7 @@ public partial class ExpressionEvaluator
 
         protected const string primaryTypesRegexPattern = @"(?<=^|[^\p{L}_])(?<primaryType>object|string|bool[?]?|byte[?]?|char[?]?|decimal[?]?|double[?]?|short[?]?|int[?]?|long[?]?|sbyte[?]?|float[?]?|ushort[?]?|uint[?]?|ulong[?]?|void)(?=[^a-zA-Z_]|$)";
 
-        protected static readonly Regex varOrFunctionRegEx = new Regex(@"^((?<sign>[+-])|(?<prefixOperator>[+][+]|--)|(?<varKeyword>var)\s+|(?<dynamicKeyword>dynamic)\s+|(?<inObject>(?<nullConditional>[?])?\.)?)(?<name>[\p{L}_](?>[\p{L}_0-9]*))(?>\s*)((?<assignationOperator>(?<assignmentPrefix>[+\-*/%&|^]|<<|>>)?=(?![=>]))|(?<postfixOperator>([+][+]|--)(?![\p{L}_0-9]))|((?<isgeneric>[<](?>([\p{L}_](?>[\p{L}_0-9]*)|(?>\s+)|[,\.])+|(?<gentag>[<])|(?<-gentag>[>]))*(?(gentag)(?!))[>])?(?<isfunction>[(])?))", RegexOptions.IgnoreCase | RegexOptions.Compiled);
+        protected static readonly Regex varOrFunctionRegEx = new Regex(@"^((?<sign>[+-])|(?<prefixOperator>[+][+]|--)|(?<varKeyword>var)\s+|(?<dynamicKeyword>dynamic)\s+|(?<inObject>(?<nullConditional>[?])?\.)?)(?<name>[\p{L}_](?>[\p{L}_0-9]*))(?>\s*)((?<assignationOperator>(?<assignmentPrefix>[+\-*/%&|^]|<<|>>|\?\?)?=(?![=>]))|(?<postfixOperator>([+][+]|--)(?![\p{L}_0-9]))|((?<isgeneric>[<](?>([\p{L}_](?>[\p{L}_0-9]*)|(?>\s+)|[,\.])+|(?<gentag>[<])|(?<-gentag>[>]))*(?(gentag)(?!))[>])?(?<isfunction>[(])?))", RegexOptions.IgnoreCase | RegexOptions.Compiled);
 
         protected const string numberRegexOrigPattern = @"^(?<sign>[+-])?([0-9][0-9_{1}]*[0-9]|\d)(?<hasdecimal>{0}?([0-9][0-9_]*[0-9]|\d)(e[+-]?([0-9][0-9_]*[0-9]|\d))?)?(?<type>ul|[fdulm])?";
         protected string numberRegexPattern;
@@ -39,7 +39,7 @@ public partial class ExpressionEvaluator
         protected static readonly Regex stringBeginningRegex = new Regex("^(?<interpolated>[$])?(?<escaped>[@])?[\"]", RegexOptions.Compiled);
         protected static readonly Regex internalCharRegex = new Regex(@"^['](\\[\\'0abfnrtv]|[^'])[']", RegexOptions.Compiled);
         protected static readonly Regex indexingBeginningRegex = new Regex(@"^[?]?\[", RegexOptions.Compiled);
-        protected static readonly Regex assignationOrPostFixOperatorRegex = new Regex(@"^(?>\s*)((?<assignmentPrefix>[+\-*/%&|^]|<<|>>)?=(?![=>])|(?<postfixOperator>([+][+]|--)(?![\p{L}_0-9])))");
+        protected static readonly Regex assignationOrPostFixOperatorRegex = new Regex(@"^(?>\s*)((?<assignmentPrefix>[+\-*/%&|^]|<<|>>|\?\?)?=(?![=>])|(?<postfixOperator>([+][+]|--)(?![\p{L}_0-9])))");
         protected static readonly Regex genericsDecodeRegex = new Regex("(?<name>[^,<>]+)(?<isgeneric>[<](?>[^<>]+|(?<gentag>[<])|(?<-gentag>[>]))*(?(gentag)(?!))[>])?", RegexOptions.Compiled);
         protected static readonly Regex genericsEndOnlyOneTrim = new Regex(@"(?>\s*)[>](?>\s*)$", RegexOptions.Compiled);