Use C# 12 syntax

src/Markdig/Extensions/Abbreviations/AbbreviationParser.cs

@@ -20,7 +20,7 @@ public class AbbreviationParser : BlockParser
     /// </summary>
     public AbbreviationParser()
     {
-        OpeningCharacters = new[] { '*' };
+        OpeningCharacters = ['*'];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)

src/Markdig/Extensions/AutoIdentifiers/AutoIdentifierExtension.cs

@@ -2,8 +2,6 @@
 // This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.
 
-using System.IO;
-
 using Markdig.Helpers;
 using Markdig.Parsers;
 using Markdig.Renderers;

src/Markdig/Extensions/AutoLinks/AutoLinkExtension.cs

@@ -11,14 +11,9 @@ namespace Markdig.Extensions.AutoLinks;
 /// Extension to automatically create <see cref="LinkInline"/> when a link url http: or mailto: is found.
 /// </summary>
 /// <seealso cref="IMarkdownExtension" />
-public class AutoLinkExtension : IMarkdownExtension
+public class AutoLinkExtension(AutoLinkOptions? options) : IMarkdownExtension
 {
-    public readonly AutoLinkOptions Options;
-
-    public AutoLinkExtension(AutoLinkOptions? options)
-    {
-        Options = options ?? new AutoLinkOptions();
-    }
+    public readonly AutoLinkOptions Options = options ?? new AutoLinkOptions();
 
     public void Setup(MarkdownPipelineBuilder pipeline)
     {

src/Markdig/Extensions/AutoLinks/AutoLinkParser.cs

@@ -22,14 +22,14 @@ public AutoLinkParser(AutoLinkOptions options)
     {
         Options = options ?? throw new ArgumentNullException(nameof(options));
 
-        OpeningCharacters = new char[]
-        {
+        OpeningCharacters =
+        [
             'h', // for http:// and https://
             'f', // for ftp://
             'm', // for mailto:
             't', // for tel:
             'w', // for www.
-        };
+        ];
 
         _listOfCharCache = new ListOfCharCache();
     }

src/Markdig/Extensions/CustomContainers/CustomContainerParser.cs

@@ -17,7 +17,7 @@ public class CustomContainerParser : FencedBlockParserBase<CustomContainer>
     /// </summary>
     public CustomContainerParser()
     {
-        OpeningCharacters = new [] {':'};
+        OpeningCharacters = [':'];
 
         // We don't need a prefix
         InfoPrefix = null;

src/Markdig/Extensions/DefinitionLists/DefinitionListParser.cs

@@ -18,7 +18,7 @@ public class DefinitionListParser : BlockParser
     /// </summary>
     public DefinitionListParser()
     {
-        OpeningCharacters = new [] {':', '~'};
+        OpeningCharacters = [':', '~'];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)

src/Markdig/Extensions/Emoji/EmojiMapping.cs

@@ -1786,6 +1786,6 @@ public EmojiMapping(IDictionary<string, string> shortcodeToUnicode, IDictionary<
                 ThrowHelper.ArgumentException(string.Format("Smiley {0} is already present in the emoji mapping", smiley.Key));
         }
 
-        OpeningCharacters = new List<char>(firstChars).ToArray();
+        OpeningCharacters = [.. firstChars];
     }
 }

src/Markdig/Extensions/Figures/FigureBlockParser.cs

@@ -18,7 +18,7 @@ public class FigureBlockParser : BlockParser
     /// </summary>
     public FigureBlockParser()
     {
-        OpeningCharacters = new[] { '^' };
+        OpeningCharacters = ['^'];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)

src/Markdig/Extensions/Footers/FooterBlockParser.cs

@@ -19,7 +19,7 @@ public class FooterBlockParser : BlockParser
     /// </summary>
     public FooterBlockParser()
     {
-        OpeningCharacters = new[] {'^'};
+        OpeningCharacters = ['^'];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)

src/Markdig/Extensions/Footnotes/FootnoteParser.cs

@@ -22,7 +22,7 @@ public class FootnoteParser : BlockParser
 
     public FootnoteParser()
     {
-        OpeningCharacters = new [] {'['};
+        OpeningCharacters = ['['];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)
@@ -49,7 +49,7 @@ private BlockState TryOpen(BlockProcessor processor, bool isContinue)
 
         // Advance the column
         int deltaColumn = processor.Start - start;
-        processor.Column = processor.Column + deltaColumn;
+        processor.Column += deltaColumn;
 
         processor.NextChar(); // Skip ':'
 
@@ -170,10 +170,8 @@ private void Document_ProcessInlinesEnd(InlineProcessor state, Inline? inline)
                 paragraphBlock = new ParagraphBlock();
                 footnote.Add(paragraphBlock);
             }
-            if (paragraphBlock.Inline == null)
-            {
-                paragraphBlock.Inline = new ContainerInline();
-            }
+
+            paragraphBlock.Inline ??= new ContainerInline();
 
             foreach (var link in footnote.Links)
             {

src/Markdig/Extensions/GenericAttributes/GenericAttributesParser.cs

@@ -23,7 +23,7 @@ public class GenericAttributesParser : InlineParser
     /// </summary>
     public GenericAttributesParser()
     {
-        OpeningCharacters = new[] { '{' };
+        OpeningCharacters = ['{'];
     }
 
     public override bool Match(InlineProcessor processor, ref StringSlice slice)
@@ -136,10 +136,7 @@ public static bool TryParse(ref StringSlice slice, [NotNullWhen(true)] out HtmlA
                 var text = slice.Text.Substring(start, end - start + 1);
                 if (isClass)
                 {
-                    if (classes is null)
-                    {
-                        classes = new List<string>();
-                    }
+                    classes ??= new List<string>();
                     classes.Add(text);
                 }
                 else

src/Markdig/Extensions/Mathematics/MathBlockParser.cs

@@ -20,7 +20,7 @@ public class MathBlockParser : FencedBlockParserBase<MathBlock>
     /// </summary>
     public MathBlockParser()
     {
-        OpeningCharacters = new [] {'$'};
+        OpeningCharacters = ['$'];
         // We expect to match only a $$, no less, no more
         MinimumMatchCount = 2;
         MaximumMatchCount = 2;

src/Markdig/Extensions/Mathematics/MathInlineParser.cs

@@ -21,7 +21,7 @@ public class MathInlineParser : InlineParser
     /// </summary>
     public MathInlineParser()
     {
-        OpeningCharacters = new[] { '$' };
+        OpeningCharacters = ['$'];
         DefaultClass = "math";
     }
 

src/Markdig/Extensions/MediaLinks/HostProviderBuilder.cs

@@ -11,23 +11,19 @@ namespace Markdig.Extensions.MediaLinks;
 
 public class HostProviderBuilder
 {
-    private sealed class DelegateProvider : IHostProvider
+    private sealed class DelegateProvider(
+        string hostPrefix,
+        Func<Uri, string?> handler,
+        bool allowFullscreen = true,
+        string? className = null) : IHostProvider
     {
-        public DelegateProvider(string hostPrefix, Func<Uri, string?> handler, bool allowFullscreen = true, string? className = null)
-        {
-            HostPrefix = hostPrefix;
-            Delegate = handler;
-            AllowFullScreen = allowFullscreen;
-            Class = className;
-        }
-
-        public string HostPrefix { get; }
+        public string HostPrefix { get; } = hostPrefix;
 
-        public Func<Uri, string?> Delegate { get; }
+        public Func<Uri, string?> Delegate { get; } = handler;
 
-        public bool AllowFullScreen { get; }
+        public bool AllowFullScreen { get; } = allowFullscreen;
 
-        public string? Class { get; }
+        public string? Class { get; } = className;
 
         public bool TryHandle(Uri mediaUri, bool isSchemaRelative, [NotNullWhen(true)] out string? iframeUrl)
         {
@@ -71,7 +67,7 @@ public static IHostProvider Create(string hostPrefix, Func<Uri, string?> handler
 
     #region Known providers
 
-    private static readonly string[] SplitAnd = { "&" };
+    private static readonly string[] SplitAnd = ["&"];
     private static string[] SplitQuery(Uri uri)
     {
         var query = uri.Query.Substring(uri.Query.IndexOf('?') + 1);

src/Markdig/Extensions/NoRefLinks/NoFollowLinksExtension.cs

@@ -17,7 +17,7 @@ public class NoFollowLinksExtension : IMarkdownExtension
 
     public NoFollowLinksExtension()
     {
-        _referralLinksExtension = new ReferralLinksExtension(new[] { "nofollow" });
+        _referralLinksExtension = new ReferralLinksExtension(["nofollow"]);
     }
 
     public void Setup(MarkdownPipelineBuilder pipeline)

src/Markdig/Extensions/SmartyPants/SmartyPantsInlineParser.cs

@@ -19,7 +19,7 @@ public class SmartyPantsInlineParser : InlineParser, IPostInlineProcessor
     /// </summary>
     public SmartyPantsInlineParser()
     {
-        OpeningCharacters = new[] {'\'', '"', '<', '>', '.', '-'};
+        OpeningCharacters = ['\'', '"', '<', '>', '.', '-'];
     }
 
     public override bool Match(InlineProcessor processor, ref StringSlice slice)

src/Markdig/Extensions/Tables/GridTableParser.cs

@@ -12,7 +12,7 @@ public class GridTableParser : BlockParser
 {
     public GridTableParser()
     {
-        OpeningCharacters = new[] { '+' };
+        OpeningCharacters = ['+'];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)
@@ -144,7 +144,7 @@ private static void SetRowSpanState(List<GridTableState.ColumnSlice> columns, St
                 line.Start = lineStart + columnSlice.Start + 1;
                 line.End = lineStart + columnSlice.End - 1;
                 line.Trim();
-                if (line.IsEmptyOrWhitespace() || !IsRowSeperator(line))
+                if (line.IsEmptyOrWhitespace() || !IsRowSeparator(line))
                 {
                     hasRowSpan = true;
                     columnSlice.CurrentCell.RowSpan++;
@@ -158,7 +158,7 @@ private static void SetRowSpanState(List<GridTableState.ColumnSlice> columns, St
         }
     }
 
-    private static bool IsRowSeperator(StringSlice slice)
+    private static bool IsRowSeparator(StringSlice slice)
     {
         char c = slice.CurrentChar;
         do
@@ -263,7 +263,7 @@ private BlockState HandleContents(BlockProcessor processor, GridTableState table
             }
             sliceForCell.TrimEnd();
 
-            if (!isRowLine || !IsRowSeperator(sliceForCell))
+            if (!isRowLine || !IsRowSeparator(sliceForCell))
             {
                 if (columnSlice.CurrentCell is null)
                 {
@@ -273,10 +273,7 @@ private BlockState HandleContents(BlockProcessor processor, GridTableState table
                         ColumnIndex = i
                     };
 
-                    if (columnSlice.BlockProcessor is null)
-                    {
-                        columnSlice.BlockProcessor = processor.CreateChild();
-                    }
+                    columnSlice.BlockProcessor ??= processor.CreateChild();
 
                     // Ensure that the BlockParser is aware that the TableCell is the top-level container
                     columnSlice.BlockProcessor.Open(columnSlice.CurrentCell);

src/Markdig/Extensions/Tables/GridTableState.cs

@@ -10,21 +10,15 @@ namespace Markdig.Extensions.Tables;
 /// <summary>
 /// Internal state used by the <see cref="GridTableParser"/>
 /// </summary>
-internal sealed class GridTableState
+internal sealed class GridTableState(int start, bool expectRow)
 {
-    public GridTableState(int start, bool expectRow)
-    {
-        Start = start;
-        ExpectRow = expectRow;
-    }
-
-    public int Start { get; }
+    public int Start { get; } = start;
 
     public StringLineGroup Lines;
 
     public List<ColumnSlice>? ColumnSlices { get; private set; }
 
-    public bool ExpectRow { get; }
+    public bool ExpectRow { get; } = expectRow;
 
     public int StartRowGroup { get; set; }
 
@@ -45,26 +39,18 @@ public void AddColumn(int start, int end, TableColumnAlign? align)
         ColumnSlices.Add(new ColumnSlice(start, end, align));
     }
 
-    public sealed class ColumnSlice
+    public sealed class ColumnSlice(int start, int end, TableColumnAlign? align)
     {
-        public ColumnSlice(int start, int end, TableColumnAlign? align)
-        {
-            Start = start;
-            End = end;
-            Align = align;
-            CurrentColumnSpan = -1;
-        }
-
         /// <summary>
         /// Gets or sets the index position of this column (after the |)
         /// </summary>
-        public int Start { get; }
+        public int Start { get; } = start;
 
-        public int End { get; }
+        public int End { get; } = end;
 
-        public TableColumnAlign? Align { get; }
+        public TableColumnAlign? Align { get; } = align;
 
-        public int CurrentColumnSpan { get; set; }
+        public int CurrentColumnSpan { get; set; } = -1;
 
         public int PreviousColumnSpan { get; set; }
 

src/Markdig/Extensions/Tables/PipeTableBlockParser.cs

@@ -22,7 +22,7 @@ public class PipeTableBlockParser : BlockParser
     /// </summary>
     public PipeTableBlockParser()
     {
-        OpeningCharacters = new[] {'-'};
+        OpeningCharacters = ['-'];
     }
 
     public override BlockState TryOpen(BlockProcessor processor)

src/Markdig/Extensions/Tables/PipeTableParser.cs

@@ -25,12 +25,12 @@ public class PipeTableParser : InlineParser, IPostInlineProcessor
     /// <summary>
     /// Initializes a new instance of the <see cref="PipeTableParser" /> class.
     /// </summary>
-    /// <param name="lineBreakParser">The linebreak parser to use</param>
+    /// <param name="lineBreakParser">The line break parser to use</param>
     /// <param name="options">The options.</param>
     public PipeTableParser(LineBreakInlineParser lineBreakParser, PipeTableOptions? options = null)
     {
         this.lineBreakParser = lineBreakParser ?? throw new ArgumentNullException(nameof(lineBreakParser));
-        OpeningCharacters = new[] { '|', '\n', '\r' };
+        OpeningCharacters = ['|', '\n', '\r'];
         Options = options ?? new PipeTableOptions();
     }
 
@@ -637,10 +637,10 @@ private sealed class TableState
 
         public int LineIndex { get; set; }
 
-        public List<Inline> ColumnAndLineDelimiters { get; } = new();
+        public List<Inline> ColumnAndLineDelimiters { get; } = [];
 
-        public List<TableCell> Cells { get; } = new();
+        public List<TableCell> Cells { get; } = [];
 
-        public List<Inline> EndOfLines { get; } = new();
+        public List<Inline> EndOfLines { get; } = [];
     }
 }

src/Markdig/Extensions/TaskLists/TaskListInlineParser.cs

@@ -19,7 +19,7 @@ public class TaskListInlineParser : InlineParser
     /// </summary>
     public TaskListInlineParser()
     {
-        OpeningCharacters = new[] {'['};
+        OpeningCharacters = ['['];
         ListClass = "contains-task-list";
         ListItemClass = "task-list-item";
     }

src/Markdig/Extensions/Yaml/YamlFrontMatterParser.cs

@@ -26,7 +26,7 @@ public class YamlFrontMatterParser : BlockParser
     /// </summary>
     public YamlFrontMatterParser()
     {
-        this.OpeningCharacters = new[] { '-' };
+        OpeningCharacters = ['-'];
     }
 
     /// <summary>