Note that it won't work on references.

sub PI { 4 * atan2 1, 1 }
print "The value of PI is ${\~~PI}\n";
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The value of PI is 3

The truth is: bitwise not only works on strings, and on integers. It works differently on both, though the net result of double not is pretty the same: restoration of the original string, or the original integer.

Thanks for pointing out a new idiom for me (which may not be all that necessary but is definately interesting to understand).

In the spirit of exploration I found that the following will also at least compile and force scalar context. Some of them will mangle return values though. ;)

sub context {
    print wantarray ? "List\n" : "Scalar\n";
}


my $string;

$string = "Test ${\~~context()} string";
$string = "Test ${\!!context()} string";
$string = "Test ${\+-+context()} string";
$string = "Test ${\-+-context()} string";
$string = "Test ${\&\&context()} string";
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Thanks again...

I found that the following will also at least compile and force scalar context. Some of them will mangle return values though. ;)

Actually, of the four additional combinations you tried, only -+- would be at all useful. It avoids mangling integers and floats. The three others mangle everything.¹ Also, with 5.6.1 and 5.8.0 at least, using this will cause warnings about ambiguity unless warnings are explicitly disabled.

Still, it may have some golf merit in being a short way to impose scalar context on functions that return floating point numbers. For strings or ints, though, I think ~~ is still preferable. For golf or obfuscation that is. Of course, scalar() is far better for "real" code.

By the way, -+- might also be written as - -, the plus or space only being necessary to differentiate it from a decrement.

1. In fact, &\& will, I think, always fail under strict checking.

-sauoq
"My two cents aren't worth a dime.";

I think these CAN be useful ... for decorative purposes ...

$arg1 = "arg1";
$arg2 = "arg2";
$arg3 = "arg3";
 
sub f1 { return "1"; }
sub f2 { return "0"; }
sub f3 { return "3"; }

print "${\-+- f1( $arg1 )}";
print "${\+-+ f2( $arg2 )}";
print "${\-+- f3( $arg3 )}";
print "\n"
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isn't that far better than the undecorated print statements? ( Same f1(), f2(), f3(), $arg1, $arg2, $arg3. )

print f1( $arg1 );
print f2( $arg2 );
print f3( $arg3 );
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And FAR superior to the boring and mundane:

print "103\n";
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--
TTTATCGGTCGTTATATAGATGTTTGCA

Far better indeed, as your "undecorated print statements" don't interpolate the function f1, f2 and f3; they just print the literal text f1( ... ).

The "decorative" version executes f1() with $arg1 as its parameter.

Of course neither approach is better than print "@{[f1( $arg1 )]}";, and that method is, itself, usually worse than print f1( $arg1 ); (without unnecessary interpolation).



Dave

"If I had my life to live over again, I'd be a plumber." -- Albert Einstein