- Begin Message From Paul Robinson -
-- First Example --
{$MACRO ON }
{$DEFINE XX1:=' This is from Macro1' }
{$DEFINE XX2:=' This is from Macro2' }
{$DEFINE XX3:=' This is from Macro3' }
{$DEFINE XX1:=' This is from Macro1A' }
{$DEFINE XX2:=' This is from Macro2A' }
{$DEFINE XX3:=' This is from Macro3A' }
Begin
    writeln('*EXAMPLES*');
    Writeln('M1: ', XX1);
    writeln('M2: ', XX2);
    writeln('M3: ', XX3);
    writeln('*END EXAMPLES');
    readln;
end.

*EXAMPLES*
M1:  This is from Macro1A
M2:  This is from Macro2A
M3:  This is from Macro3A
*END EXAMPLES

--- Second Example ---
{$MACRO ON }
{*$DEFINE XX1:=' This is from Macro1' *)
{$DEFINE XX2:=' This is from Macro2' }
{$DEFINE XX3:=' This is from Macro3' }
{$DEFINE XX1:=' This is from Macro1A' }
{$DEFINE XX2:=' This is from Macro2A' }
{$DEFINE XX3:=' This is from Macro3A' }
Begin
    writeln('*EXAMPLES*');
    Writeln('M1: ', XX1);
    writeln('M2: ', XX2);
    writeln('M3: ', XX3);
    writeln('*END EXAMPLES');
    readln;
end.

This returns a compiler error indicating end of file.

--- Third Example ---
{$MACRO ON }
{$DEFINE XX1:=' This is from Macro1' }
{$DEFINE XX2:=' This is from Macro2' }
{$DEFINE XX3:=' This is from Macro3' }
//$DEFINE XX1:=' This is from Macro1A'
{$DEFINE XX2:=' This is from Macro2A' }
{$DEFINE XX3:=' This is from Macro3A' }
Begin
    writeln('*EXAMPLES*');
    Writeln('M1: ', XX1);
    writeln('M2: ', XX2);
    writeln('M3: ', XX3);
    writeln('*END EXAMPLES');
    readln;
end.

*EXAMPLES*
M1:  This is from Macro1
M2:  This is from Macro2A
M3:  This is from Macro3A
*END EXAMPLES

This proves conclusively that only open brace { comment is acceptable for defining macros in Free Pascal. ----
The Lessons of History teach us - if they teach us anything - that no one learns the lessons that history teaches us.
- Message Ends-

Paul Robinson wrote

--- Second Example --- {$MACRO ON } {*$DEFINE XX1:=' This is from Macro1' *)

This is wrong code. You cannot open a comment with { and close it with *)

(* matches *)
{ matches only }
{* means nothing special, it is a { comment opening followed by a character * inside the comment.

I think that was a typo.

program testmacros;
{$MACRO ON }
{$DEFINE XX1:=' This is from Macro1' }
{$DEFINE XX2:=' This is from Macro2' }
{$DEFINE XX3:=' This is from Macro3' }
(*$DEFINE XX1:=' This is from Macro1A' *)
{$DEFINE XX2:=' This is from Macro2A' }
{$DEFINE XX3:=' This is from Macro3A' }
Begin
     writeln('*EXAMPLES*');
     Writeln('M1: ', XX1);
     writeln('M2: ', XX2);
     writeln('M3: ', XX3);
     writeln('*END EXAMPLES');
     readln;
end.

0 2> fpc testmacros
Free Pascal Compiler version 2.7.1 [2011/12/23] for sparc Copyright (c) 1993-2011 by Florian Klaempfl and others Target OS: Linux for SPARC
Compiling testmacros.pas
testmacros.pas(25) Fatal: Unexpected end of file
Fatal: Compilation aborted
Error: /usr/local/bin/ppcsparc returned an error exitcode (normal if you did not specify a source file to be compiled)

From: Felipe Monteiro de Carvalho

Paul Robinson wrote

--- Second Example --- {$MACRO ON } {*$DEFINE XX1:=' This is from Macro1' *)

This is wrong code. You cannot open a comment with { and close it with *)

I may have misread the brace when I typed it, but this one I checked Line 6 three times to ensure the comment opens with (* and closes with *)

{$MACRO ON }
{$DEFINE XX1:=' This is from Macro1' }
{$DEFINE XX2:=' This is from Macro2' }
{$DEFINE XX3:=' This is from Macro3' }
(*$DEFINE XX1:=' This is from Macro1A' *)
{$DEFINE XX2:=' This is from Macro2A' }
{$DEFINE XX3:=' This is from Macro3A' }
Begin
    writeln('*EXAMPLES*');
    Writeln('M1: ', XX1);
    writeln('M2: ', XX2);
    writeln('M3: ', XX3);
    writeln('*END EXAMPLES');
    readln;
end.

And again, it tells me the source code terminates prematurely.

This proves conclusively that only open brace { comment is acceptable for defining macros in Free Pascal.

The scanner for comments is highly optimized (manually), resulting in unwanted inconsistent and untested behaviour :-(

The preprocessor is broken since the time, when somebody decided to make the scanner a class, and didn't know how to update the preprocessor part accordingly. I've supplied an patch to make the preprocessor work again, but it didn't find its way into the compiler yet :-(

DoDi