Group comment

[Bengt Richter]

On Mon, 1 Mar 2004 08:57:56 -0600, Skip Montanaro <skip at pobox.com> wrote:

>
>    ketulp> Can I comment a group of statements together i.e
>    ketulp> If I a 4 statements say:
>    ketulp> i=1
>    ketulp> i+=1
>    ketulp> print i
>    ketulp> print i+1
>
>    ketulp> Instead of commenting each satement iindividually by # is there
>    ketulp> something which allws me to comment these 4 statements in one go
>    ketulp> as in C++ using /*...*/
>
>Many people use triple-quoted strings for this:
>
>    """
>    i=1
>    i+=1
>    print i
>    print i+1
>    """

Though there's always the corner case where there's already something triple-quoted in
the segment you want to comment/quote out.

If we had string-delimited quoting a la mime, we could solve that. E.g.,

    q'arbitrary string'<this is '''quoted''' and """triple is ignored""" ...>'arbitrary string'

or
    Q'arbitrary string'
<this is '''quoted''' and """triple is ignored""" ...>
'arbitrary string'

Where the upper case Q signals the syntax that the line tail after the delimiter is ignored.
(thus the second quote above also includes the \n at the end of the quoted < ...> line)


thus

     Q'XXX'
     i=1
     i+=1
     print i
     print i+1
     'XXX'

and then no problem to do:

  Q'YYY'
     Q'XXX'
     i=1
     i+=1
     print i
     print i+1
     'XXX'
  'YYY'

(The single quotes are for readability, not part of the actual quoting delimiters)
You could deal with the final-escape char problem if you had a no-escapes raw string
version of this. Maybe signal that with double quoted delimiter strings, e.g.,

    q"+++"this ends in backslash\"+++"

which would define the same string constant as 'this ends in backslash\\'


>
>It's not a comment, strictly speaking, however it generally achieves the
>desired results.  Even less comment-like is "if False:":
>
>    if False:
>        i=1
>        i+=1
>        print i
>        print i+1
>
>That has the disadvantage that you need to reindent the lines of interest.

The other side of the coin is that it's sometimes useful to write

    if True:
        # .. pasted code that has indentation

"if True" is also handy to defer processing in interactive mode, e.g.,

 >>> print 'hi'
 hi
 >>> print 'ho'
 ho
 >>> if True:
 ...     print 'hi'
 ...     print 'ho'
 ...
 hi
 ho

That's my clpy quota for today ;-)

Regards,
Bengt Richter