expression eats newline

[Gerard Oberle]

The following Perl script

print ((time/86400) % 4), " foo foo foo foo\n";
print "bar\n";

produces the output

0bar

What happened to " foo foo foo foo\n"?

print 12, " foo\n";

prints '12 foo' and a newline. Ergo, ((time/86400) % 4) should just
be another numeric expression, just like 12, shouldn't it? Or am I
missing something really stupid?

Thanks in advance.
- Jerry Oberle
perl -e 'printf "mailto%c%s%c%s%cchase%ccom%c", 58, "Gerard", 46,
"Oberle", 64, 46, 10;'

 

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Gerard Oberle wrote:

(snipped)

The following Perl script

print ((time/86400) % 4), " foo foo foo foo\n";
print "bar\n";

produces the output

What happened to " foo foo foo foo\n"?

You are neglecting Perl command formats, which are
typically, command() as with print().

Your parentheses are the problem. Perl is doing
precisely what your syntax indicates to do.

Compare these to your syntax:

print time/86400 % 4, " foo foo foo foo\n";
print "bar\n";

print (((time/86400) % 4), " foo foo foo foo\n");
print "bar\n";


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--

#!perl -w

print ((time/86400) % 4), " foo foo foo foo\n";
print "bar\n";


PRINTED RESULTS:
________________

print (...) interpreted as function at test.pl line 3.
Useless use of a constant in void context at test.pl line 3.
0bar

 

[Eric J. Roode]

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(e-mail address removed) (Gerard Oberle) wrote in

The following Perl script

print ((time/86400) % 4), " foo foo foo foo\n";

Perl has a rule when it comes to interpreting statements like this:

"if it looks like a function, it IS a function."

So, because of your parentheses, it is as if you wrote:

$x = print( (time/86400)%4 );
$x, " foo foo foo foo\n";

The solution is either to add a + before the first parenthesis:

print +((time/86400) % 4), " foo foo foo foo\n";

or to add another set of parentheses:

print (((time/86400) % 4), " foo foo foo foo\n");


For your future reference, comp.lang.perl is a defunct newsgroup. General
perl questions should be posted to comp.lang.perl.misc; you'll get a better
response there.
- --
Eric
$_ = reverse sort qw p ekca lre Js reh ts
p, $/.r, map $_.$", qw e p h tona e; print

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dlcsK2oa9GH1M3p1WYE8AUVW
=2btu
-----END PGP SIGNATURE-----

 

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Gerard Oberle wrote:

(Topic is use of parentheses with Perl print)

(snipped)

As I suspected, I was missing something stupid.

Not really stupid. It is very rare to read Perl code
which employs C style parentheses with a print command.
Almost all books and reference sources omit parentheses
within examples of print commands. Most do not know of
this until a rather quirky problem pops up.

As for comp.lang.perl being defunct, I am not sure how one can
determine that. groups.google.com still carries it, and there are
lots of recent postings, so I assume people are still using it.

Many if not most news servers carry this group and alt.perl as well.
Humors me when reading those proclaiming this group does not exist.
Quite the oxymoron, this is, posting to a group which does not exist.


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