Support for markdown output in help messages

This functionality can be used to provide on-line versions of the help
messages for alire.ada.dev.

The help is generated in a single markdown page with appropiate
section titles, so it can have a table of contents.

src/alr/alr-commands-dev.adb

@@ -1,5 +1,8 @@
+with Ada.Strings.Unbounded;
 with Ada.Strings.UTF_Encoding.Wide_Wide_Strings;
 
+with CLIC.Formatter;
+
 with Alire.Selftest;
 
 package body Alr.Commands.Dev is
@@ -24,6 +27,58 @@ package body Alr.Commands.Dev is
       Trace.Always (Encode ("ⓘ✓"));
    end Print_UTF_8_Sequence;
 
+   -------------------
+   -- Print_MD_Help --
+   -------------------
+
+   procedure Print_MD_Help is
+
+      use Ada.Strings.Unbounded;
+
+      Last_Group : Unbounded_String;
+
+      procedure Put_MD_Command
+        (Group : Unbounded_String;
+         Cmd : not null CLIC.Subcommand.Command_Access) is
+      begin
+
+         if Group /= Last_Group then
+            New_Line;
+            Put_Line ("# " & To_String (Group) & " Commands");
+
+            Last_Group := Group;
+         end if;
+
+         Put_Line ("## `alr " & Cmd.Name & "`");
+
+         New_Line;
+         Sub_Cmd.Display_Help (Cmd.Name);
+         New_Line;
+
+      end Put_MD_Command;
+
+      procedure Put_MD_Topic
+        (Topic : not null CLIC.Subcommand.Help_Topic_Access) is
+      begin
+         New_Line;
+         Put_Line ("## " & Topic.Name);
+         Sub_Cmd.Display_Help (Topic.Name);
+         New_Line;
+      end Put_MD_Topic;
+
+   begin
+      CLIC.Formatter.Enable_Markdown;
+
+      Put_Line ("# Usage Help");
+      Sub_Cmd.Display_Usage;
+
+      Sub_Cmd.Iterate_Commands (Process => Put_MD_Command'Access);
+
+      Put_Line ("# Topics");
+      Sub_Cmd.Iterate_Topics (Process => Put_MD_Topic'Access);
+
+   end Print_MD_Help;
+
    -------------
    -- Execute --
    -------------
@@ -56,6 +111,10 @@ package body Alr.Commands.Dev is
       if Cmd.UTF_8_Test then
          Print_UTF_8_Sequence;
       end if;
+
+      if Cmd.MD_Help then
+         Print_MD_Help;
+      end if;
    end Execute;
 
    ----------------------
@@ -105,6 +164,11 @@ package body Alr.Commands.Dev is
                      Cmd.UTF_8_Test'Access,
                      "", "--utf8",
                      "Print a known UTF-8 sequence");
+
+      Define_Switch (Config,
+                     Cmd.MD_Help'Access,
+                     "", "--help-doc-markdown",
+                     "Print a complete help page in markdown format");
    end Setup_Switches;
 
 end Alr.Commands.Dev;

src/alr/alr-commands-dev.ads

@@ -37,6 +37,7 @@ private
       Raise_Except : aliased Boolean := False;
       Self_Test    : aliased Boolean := False;
       UTF_8_Test   : aliased Boolean := False; -- Produce some UTF-8 output
+      MD_Help      : aliased Boolean := False;
    end record;
 
 end Alr.Commands.Dev;

src/alr/alr-commands.adb

@@ -452,7 +452,7 @@ package body Alr.Commands is
       end if;
 
       if No_TTY then
-         CLIC.TTY.Force_Disable_TTY;
+         CLIC.Formatter.Force_Disable_TTY;
       end if;
 
       --  Use CLIC.TTY selection/detection of TTY

src/alr/alr-commands.ads

@@ -6,6 +6,7 @@ with Alire.Solver;
 with Alire.Version;
 
 with CLIC.Subcommand;
+with CLIC.Formatter;
 
 private with GNAT.IO;
 private with CLIC.Subcommand.Instance;
@@ -143,11 +144,11 @@ private
       Put_Error           => Put_Error,
       Error_Exit          => OS_Lib.Bailout,
       Set_Global_Switches => Set_Global_Switches,
-      TTY_Chapter         => Alire.TTY.Bold,
-      TTY_Description     => Alire.TTY.Description,
-      TTY_Version         => Alire.TTY.Version,
-      TTY_Underline       => Alire.TTY.Underline,
-      TTY_Emph            => Alire.TTY.Emph);
+      TTY_Chapter         => CLIC.Formatter.Chapter,
+      TTY_Description     => CLIC.Formatter.Description,
+      TTY_Version         => CLIC.Formatter.Version,
+      TTY_Underline       => CLIC.Formatter.Underline,
+      TTY_Emph            => CLIC.Formatter.Emph);
 
    Unset : constant String := "unset";
    --  Canary for when a string switch is given without value