* Markdown writer

packages/fcl-base/fpmake.pp

@@ -116,6 +116,11 @@ begin
         begin
           AddUnit('wformat');
         end;
+    T:=P.Targets.AddUnit('wmarkdown.pp');
+      with T.Dependencies do
+        begin
+          AddUnit('wformat');
+        end;
     T:=P.Targets.AddUnit('wtex.pp');
       with T.Dependencies do
         begin

packages/fcl-base/namespaced/Fcl.WMarkDown.pp

@@ -0,0 +1,3 @@
+unit Fcl.WMarkDown;
+{$DEFINE FPC_DOTTEDUNITS}
+{$i wmarkdown.pp}

packages/fcl-base/namespaces.lst

@@ -22,6 +22,7 @@ src/pooledmm.pp=namespaced/System.Pooledmm.pp
 src/csvreadwrite.pp=namespaced/Fcl.Csv.ReadWrite.pp
 src/idea.pp=namespaced/System.Hash.Idea.pp
 src/whtml.pp=namespaced/Fcl.Whtml.pp
+src/wmarkdown.pp=namespaced/Fcl.WMarkDown.pp
 src/csvdocument.pp=namespaced/Fcl.Csv.Document.pp
 src/gettext.pp=namespaced/System.GetText.pp
 src/chainstream.pp=namespaced/Fcl.Streams.Chained.pp

packages/fcl-base/src/wmarkdown.pp

@@ -0,0 +1,290 @@
+{
+    This file is part of the Free Component Library (Fcl)
+    Copyright (c) 2025 by the Free Pascal development team
+
+    See the file COPYING.FPC, included in this distribution,
+    for details about the copyright.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+ **********************************************************************
+
+    TMarkdownWriter - Markdown formatting writer implementation
+
+    This unit provides TMarkdownWriter, a concrete implementation of
+    TFormattingWriter that generates Markdown output. It supports:
+
+    - Document structure (headers, paragraphs)
+    - Text formatting (bold, italic, underline via HTML)
+    - Tables with proper alignment
+    - Lists (unordered, ordered, definition)
+    - Preformatted code blocks
+    - Character escaping for special markdown characters
+
+    See demo_markdown.pp for usage examples.
+
+ **********************************************************************}
+{$IFNDEF FPC_DOTTEDUNITS}
+unit wmarkdown;
+{$ENDIF FPC_DOTTEDUNITS}
+
+{$ifdef fpc}
+{$mode objfpc}
+{$endif}
+
+interface
+
+{$IFDEF FPC_DOTTEDUNITS}
+uses Fcl.Wformat,System.Classes,System.SysUtils;
+{$ELSE FPC_DOTTEDUNITS}
+uses wformat,Classes,SysUtils;
+{$ENDIF FPC_DOTTEDUNITS}
+
+Type
+  TMarkdownWriter=Class(TFormattingWriter)
+  Private
+    FTableCols: Integer;
+    FTableHeaderWritten: Boolean;
+    FInListItem: Boolean;
+  Public
+    Constructor Create (AStream : TStream); override;
+    Function EscapeText (AText : String) : String; override;
+    Procedure DocumentStart(Const Title : String); override;
+    Procedure DocumentEnd; override;
+    Procedure HeaderStart(Alevel : Integer); override;
+    Procedure HeaderEnd(Alevel : Integer); override;
+    Procedure ParagraphStart; override;
+    Procedure ParagraphEnd; override;
+    Procedure LineBreak; override;
+    Procedure Rule; override;
+    Procedure BoldStart; override;
+    Procedure BoldEnd;override;
+    Procedure ItalicStart;override;
+    Procedure ItalicEnd;override;
+    Procedure UnderlineStart;override;
+    Procedure UnderlineEnd;override;
+    Procedure PreformatStart; override;
+    Procedure PreformatEnd; override;
+    Procedure TableStart( NoCols: Integer; Border : Boolean); override;
+    Procedure TableEnd; override;
+    Procedure RowStart; override;
+    Procedure RowEnd; override;
+    Procedure CellStart; override;
+    Procedure CellEnd; override;
+    Procedure HeaderCellStart; override;
+    Procedure HeaderCellEnd; override;
+    Procedure ListStart(ListType : TListType); override;
+    Procedure ListEnd(ListType : TListType); override;
+    Procedure ListItemStart; override;
+    Procedure ListItemEnd; override;
+    Procedure DefinitionItem(Const Aname,AText : String); override;
+  end;
+
+implementation
+
+{ TMarkdownWriter }
+
+constructor TMarkdownWriter.Create(AStream: TStream);
+begin
+  inherited;
+  FTableCols := 0;
+  FTableHeaderWritten := False;
+  FInListItem := False;
+end;
+
+function TMarkdownWriter.EscapeText(AText: String): String;
+begin
+  // Only escape backslashes and characters that could break structure
+  Result := StringReplace(AText, '\', '\\', [rfReplaceAll]);
+  Result := StringReplace(Result, '[', '\[', [rfReplaceAll]);
+  Result := StringReplace(Result, ']', '\]', [rfReplaceAll]);
+  // Don't escape * _ ` # as they might be intentional formatting
+end;
+
+procedure TMarkdownWriter.DocumentStart(const Title: String);
+begin
+  if Title <> '' then
+  begin
+    Dump('# ');
+    Write(Title);
+    DumpLn('');
+    DumpLn('');
+  end;
+end;
+
+procedure TMarkdownWriter.DocumentEnd;
+begin
+  // Markdown doesn't require explicit document ending
+end;
+
+procedure TMarkdownWriter.HeaderStart(Alevel: Integer);
+var
+  HeaderMarker: String;
+  i: Integer;
+begin
+  HeaderMarker := '';
+  for i := 1 to ALevel + 1 do
+    HeaderMarker := HeaderMarker + '#';
+  Dump(HeaderMarker + ' ');
+end;
+
+procedure TMarkdownWriter.HeaderEnd(Alevel: Integer);
+begin
+  DumpLn('');
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.ParagraphStart;
+begin
+  // Markdown paragraphs don't need explicit start markers
+end;
+
+procedure TMarkdownWriter.ParagraphEnd;
+begin
+  DumpLn('');
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.LineBreak;
+begin
+  DumpLn('  '); // Two spaces at end of a line creates a line break in markdown
+end;
+
+procedure TMarkdownWriter.Rule;
+begin
+  DumpLn('');
+  DumpLn('---');
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.BoldStart;
+begin
+  Dump('**');
+end;
+
+procedure TMarkdownWriter.BoldEnd;
+begin
+  Dump('**');
+end;
+
+procedure TMarkdownWriter.ItalicStart;
+begin
+  Dump('*');
+end;
+
+procedure TMarkdownWriter.ItalicEnd;
+begin
+  Dump('*');
+end;
+
+procedure TMarkdownWriter.UnderlineStart;
+begin
+  // Markdown doesn't have native underline, use HTML
+  Dump('<u>');
+end;
+
+procedure TMarkdownWriter.UnderlineEnd;
+begin
+  Dump('</u>');
+end;
+
+procedure TMarkdownWriter.PreformatStart;
+begin
+  DumpLn('');
+  DumpLn('```');
+end;
+
+procedure TMarkdownWriter.PreformatEnd;
+begin
+  DumpLn('```');
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.TableStart(NoCols: Integer; Border: Boolean);
+begin
+  FTableCols := NoCols;
+  FTableHeaderWritten := False;
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.TableEnd;
+begin
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.RowStart;
+begin
+  Dump('|');
+end;
+
+procedure TMarkdownWriter.RowEnd;
+var
+  i: Integer;
+begin
+  DumpLn('');
+
+  // After header row, add separator row
+  if not FTableHeaderWritten then
+  begin
+    FTableHeaderWritten := True;
+    Dump('|');
+    for i := 1 to FTableCols do
+      Dump('---|');
+    DumpLn('');
+  end;
+end;
+
+procedure TMarkdownWriter.CellStart;
+begin
+  Dump(' ');
+end;
+
+procedure TMarkdownWriter.CellEnd;
+begin
+  Dump(' |');
+end;
+
+procedure TMarkdownWriter.HeaderCellStart;
+begin
+  CellStart;
+end;
+
+procedure TMarkdownWriter.HeaderCellEnd;
+begin
+  CellEnd;
+end;
+
+procedure TMarkdownWriter.ListStart(ListType: TListType);
+begin
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.ListEnd(ListType: TListType);
+begin
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.ListItemStart;
+begin
+  FInListItem := True;
+  Dump('- '); // Use dash for all list types for simplicity
+end;
+
+procedure TMarkdownWriter.ListItemEnd;
+begin
+  FInListItem := False;
+  DumpLn('');
+end;
+
+procedure TMarkdownWriter.DefinitionItem(const Aname, AText: String);
+begin
+  Write(AName);
+  DumpLn('');
+  Dump(': ');
+  Write(AText);
+  DumpLn('');
+end;
+
+end.