Re: Can we do without auxiliary variable here?

I rather like:

#!/usr/bin/perl
use warnings;
use strict;

my $prefix="prefix: ";
sub printpre {
        unshift @_, $prefix;
        print @_;
}

printpre "apple ", "banana ", "tomfoolery ", "\n";
[download]

...roboticus

When your only tool is a hammer, all problems look like your thumb.

Comment on Re: Can we do without auxiliary variable here? Download Code

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Re^2: Can we do without auxiliary variable here? by chromatic (Archbishop) on Feb 28, 2011 at 22:20 UTC
Why not write that without the auxiliary array manipulation there?	[reply]
Re^3: Can we do without auxiliary variable here? by roboticus (Chancellor) on Feb 28, 2011 at 23:07 UTC
chromatic: Ha, ha! It never occurred to me! `#!/usr/bin/perl use strict; use warnings; my $prefix="Prefix: "; sub print_prefix { print $prefix, @_; } print_prefix "alpha ", "beta ", "gamma\n";` [download] Sigh. When I read your reply, I thought, "Hmm, does unshift return a reference to the array?", so a first I thought you were prompting me to do something like: `print unshift @_, $prefix;` [download] But when I checked the docs, I could see that it wouldn't fly. Then I understood what you meant. Ah, well! I'm always amused at how my mind works: it seems I frequently complicate simple things. ;^) ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply] [d/l] [select]
Re^2: Can we do without auxiliary variable here? by ikegami (Patriarch) on Feb 28, 2011 at 23:19 UTC
It seems to me the OP has a logger and he wants to include the prefix at the start of every line, not the start of every message. Those aren't the same if there's a possibility of multi-line messages.	[reply]
Re^2: Can we do without auxiliary variable here? by rovf (Priest) on Mar 01, 2011 at 11:20 UTC
This would not cope when there are "\n" in between. See the comment by ikegami. -- Ronald Fischer <ynnor@mm.st>	[reply] [d/l]
Re^3: Can we do without auxiliary variable here? by roboticus (Chancellor) on Mar 01, 2011 at 11:38 UTC
rovf: Yeah, I clearly missed on that one. I then tried: `sub print_prefix { local $/="\nPrefix: "; print @_; }` [download] But that didn't work. On first guess, I thought it would do OK. After reading the documentation, I thought it would print it at least once. But what I got was...nothing. It never printed prefix at all. The only other methods I could think of had already been covered. ...roboticus When your only tool is a hammer, all problems look like your thumb.	[reply] [d/l]