Fix throws exception by \color

ForNeVeR · Feb 26, 2020 · 3dd72b8 · 3dd72b8
1 parent c051e6b
commit 3dd72b8
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Showing 2 changed files with 6 additions and 1 deletion.
diff --git a/src/WpfMath.Tests/ParserExceptionTests.fs b/src/WpfMath.Tests/ParserExceptionTests.fs
@@ -52,6 +52,11 @@ let ``"\binom{}" should throw a TexParseException``(): unit =
     let ex = assertParseThrows<TexParseException> @"\binom{}"
     Assert.Equal("An element is missing", ex.Message)
 
+[<Fact>]
+let ``"\color" should throw a TexParseException``(): unit =
+    let ex = assertParseThrows<TexParseException> @"\color"
+    Assert.Equal("An element is missing", ex.Message)
+
 [<Fact>]
 let ``"\color{red}" should throw a TexParseException``(): unit =
     let ex = assertParseThrows<TexParseException> @"\color{red}"

diff --git a/src/WpfMath/TexFormulaParser.cs b/src/WpfMath/TexFormulaParser.cs
@@ -349,7 +349,7 @@ private static SourceSpan ReadElementGroupOptional(
             char closeChar)
         {
             SkipWhiteSpace(value, ref position);
-            if (value[position] != openChar)
+            if (position == value.Length || value[position] != openChar)
                 return null;
 
             return ReadElementGroup(value, ref position, openChar, closeChar);