Fix TitleCase capitalization at sentence boundaries

src/Humanizer.Tests/EnumHumanizeTests.cs

@@ -176,4 +176,16 @@ enum DummyEnum
         First,
         Second
     }
+    [Fact]
+    public void Humanize_Works_For_Enum_Known_Only_At_Runtime()
+    {
+        Enum value = EnumUnderTest.MemberWithoutDescriptionAttribute;
+
+        var result = value.Humanize();
+
+        Assert.Equal(
+            EnumTestsResources.MemberWithoutDescriptionAttributeSentence,
+            result);
+    }
+
 }

src/Humanizer/EnumHumanizeExtensions.cs

@@ -26,15 +26,15 @@
     /// <code>
     /// enum UserType { AnonymousUser, RegisteredUser }
     /// UserType.AnonymousUser.Humanize() => "Anonymous user"
-    /// 
+    ///
     /// [Flags]
     /// enum Permission { None = 0, Read = 1, Write = 2, Delete = 4 }
     /// (Permission.Read | Permission.Write).Humanize() => "Read, Write"
-    /// 
-    /// enum Status 
-    /// { 
+    ///
+    /// enum Status
+    /// {
     ///     [Description("Currently active")]
-    ///     Active 
+    ///     Active
     /// }
     /// Status.Active.Humanize() => "Currently active"
     /// </code>
@@ -62,6 +62,23 @@
         return humanized[input];
     }
 
+    public static string Humanize(this Enum input)
+    {
+        if (input == null)
+            ArgumentNullException.ThrowIfNull(input);
+
+        var enumType = input.GetType();
+
+        // Get the generic Humanize<T> method
+        var method = typeof(EnumHumanizeExtensions)
+            .GetMethod(nameof(Humanize), new[] { enumType });
+
+        if (method == null)
+            throw new InvalidOperationException($"No Humanize method found for enum type {enumType}.");
+
+        return (string)method.Invoke(null, new object[] { input })!;
+    }
+
 
     /// <summary>
     /// Converts an enum value to a human-readable string with the specified letter casing applied.

src/Humanizer/Transformer/ToTitleCase.cs

@@ -10,7 +10,7 @@ public string Transform(string input) =>
 #if NET7_0_OR_GREATER
     [GeneratedRegex(WordPattern)]
     private static partial Regex WordRegexGenerated();
-    
+
     private static Regex WordRegex() => WordRegexGenerated();
 #else
     private static readonly Regex WordRegexDefinition = new(WordPattern, RegexOptions.Compiled);
@@ -26,11 +26,19 @@ public string Transform(string input, CultureInfo culture)
         foreach (Match word in matches)
         {
             var value = word.Value;
-            if (AllCapitals(value) || IsArticleOrConjunctionOrPreposition(value))
+            var isSentenceStart = IsSentenceStart(input, word.Index);
+
+            if (AllCapitals(value))
+            {
+                continue;
+            }
+
+            if (IsArticleOrConjunctionOrPreposition(value) && !isSentenceStart)
             {
                 continue;
             }
 
+
             builder[word.Index] = textInfo.ToUpper(value[0]);
             Overwrite(builder, word.Index + 1, textInfo.ToLower(value[1..]));
         }
@@ -71,4 +79,28 @@ word is
 
             // prepositions
             "as" or "at" or "by" or "for" or "in" or "of" or "off" or "on" or "to" or "up" or "via";
+
+
+    static bool IsSentenceStart(string input, int wordIndex)
+    {
+        if (wordIndex == 0)
+        {
+            return true;
+        }
+
+        for (var i = wordIndex - 1; i >= 0; i--)
+        {
+            var ch = input[i];
+
+            if (char.IsWhiteSpace(ch))
+            {
+                continue;
+            }
+
+            return ch is '.' or '!' or '?';
+        }
+
+        return true;
+    }
+
 }