title: Delphi ^A syntax: Documented, implied, or undocumented?
body: <p>Let me explain by an example. In Delphi, you can write</p>
  
  <pre><code>procedure TForm1.FormKeyPress(Sender: TObject; var Key: Char);
  begin
    if Key = ^C then
      ShowMessage('The user wants to copy something.')
    else if Key = ^V then
      ShowMessage('The user wants to paste.')
  end;
  </code></pre>
  
  <p>to check for Ctrl+C and Ctrl+V keyboard commands. In fact, the same syntax works for Ctrl+A, where A is <em>any</em> character, and -- of course -- you can also use a <code>case</code> statement instead of <code>if</code>s. You can even do <code>ShowMessage(^A)</code>, so, apparently, <code>^A</code> is considered a <code>char</code>.</p>
  
  <p>However, when browsing <a href="http://docwiki.embarcadero.com/RADStudio/en/Delphi_Language_Guide_Index" rel="noreferrer">the official Delphi documentation</a>, I cannot find any reference to this syntax. But maybe the <code>^A</code> syntax is so common that it is understood as a part of the underlying plain text file format? Or is it simply an undocumented feature of the Delphi programming language? (Notice that the above constructions are actually used in the RTL/VCL source code. But, of course, Embarcadero, and Embarcadero alone, is allowed to use undocumented features, if any such exists.)</p>