How can I comment out only part of a line in Perl?

Question

How do I comment a part of a single line in Perl, like the following line:

 if($clevel==0){#never happends}

I would like to be able to comment that last closing bracket, without going to a new line.

Answer 1

The # sign starts a comment that ends with the end of the line.

Answer 2

A # and then a line break. You can treat them as a bracket of sorts, since little in Perl looses its meaning from being on different lines.

my $ans = 2 + rand( 5 ) + $pixels / FUDGE_FACTOR;

To

my $ans = # 2 + 
    rand( 5 ) + $pixels # / FUDGE_FACTOR
    ;

Or from:

if ( dont_know_how_this_breaks() && defined $attribute ) { 
   #...
}

To:

if ( # dont_know_how_this_breaks() && 
     defined $attribute ) { 
   #...
}

Answer 3

If it's really that important, use source filtering.

# C_Style_Comments.pm
package C_Style_Comments;
use Filter::Simple;
FILTER {   s{/\* .* \*/}{}gmx    };
1;

---

$ perl -MC_Style_Comments -e 'print /* 5, No wait, I mean */ 3'
3

Answer 4

Any reason you can't write :

if($clevel==0){#never happends}

as :

if($clevel==0){} #never happens

There are some tricks you can do to hide messages, such as:

0 and 'some comment'

But you're just going to make it more confusing if someone else has to maintain your code in the future.

Working within the constraints of a language, rather than trying to force it to act like some language you're more familiar with often leads you to learn new things. I personally hate working in IDL, but some of the tricks for dealing with poor loop performance led me to optimize code I've since written in other languages.