Re: Commenting out lines

[John W. Eaton]

On  3-Aug-2004, Przemek Klosowski <address@hidden> wrote:

|    If there is I've missed it. I find it a real pain to have to put a 
|    "#" in front of each of a bunch of lines whenever I want to test an 
|    alternative method.
| 
| 
| Would it work for you to do 
| 
|     if(pi==4)
|        ... lines of code to be skipped
|     endif
| 
| Even better, you could
| 
|     if(method==3)
|        ... code for method 3
|     else if(method==4)
|        ... code for method 4
|     endif; endif

This works well most of the time and is the recommended solution (if
you don't want to use the comment-region method in Emacs).  The
disadvantage of the "if (false) ... endif" method is that the text
between the "if (false)" and "endif" must be valid Octave code.

The latest release of Matlab also introduced a block comment:

%{
  ...
%}

My understanding of the rules for this type of comment block is that

  the %{ and %} tokens must begin in column 1 (so a "%}" token that
  does not begin in column 1 is not recognized as an end comment
  region token)

  the blocks may be nested (so the begin and end comment region tokens
  must be balanced)

  any text (not just valid code) may appear between the begin and end
  comment region tokens

The first restriction is unfortunate and I'm not sure I understand the
reason for it -- what conflict would arise without this restriction?
The unfortunate part is that it prevents you from doing useful things
like commenting out the middle of some line as you can with the
"/* ... */" comments in C.

In any case, I'm sure that eventually we will see messages here from
people wondering why Octave is so backward as to not implement this
essential feature.

jwe



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