From help-request at octave dot org Fri Apr 15 10:48:43 2005
Subject: Re: multiline comments
From: Quentin Spencer <qspencer at ieee dot org>
To: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
CC: Geordie McBain <geordie dot mcbain at aeromech dot usyd dot edu dot au>,         =?ISO-8859-1?Q?S=F8ren_Hauberg?= <soren@hauberg.org>, help@octave.org
Date: Fri, 15 Apr 2005 10:42:00 -0500

John W. Eaton wrote:

>  * Do these comments nest?  Do you get this behavior:
>
>      %{ 1
>      %{ 2
>      %} matches 2
>      %} matches 1
>
>   or
>
>      %{ 1
>      %{ 2
>      %} matches 1
>      %} error, warning, or just ignored (it is a valid comment)
>  
>
OK, I did some tests to see how it all behaves. The first thing I 
discovered is that
%{ text here
is not a valid block comment;  the characters "%{" must appear on a line 
by themselves (white space before or after is OK). It also appears that 
the comments do nest. I tested the following code with no errors:

%{   
  block-commented text
  %{
    nested block-commented text
  %}
  is this still block-commented?
%}

Deleting the final %} gives the error:
"Unterminated %{ block. Use %} to terminate."

>...
>Yes, if(0) endif is the more common way of faking block comments.  The
>disadvantage is that the text inside the if(0) endif block must be
>valid code.  In a block comment, you could have anything except "%}"
>at the beginning of a line.
>  
>
Yes, I've noticed that as well.



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