A twisty little maze of ampersands, all different


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A twisty little maze of ampersands, all different

by haj (Vicar)

on Jun 08, 2021 at 22:54 UTC ( [id://11133670]=obfuscated: print w/replies, xml )

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The following code prints a 0, a 1, a 2, and an empty line. But which is which?

use 5.020;
sub one { 1 }
sub two { 2 }

say one&two     ;
say &one&two    ;
say &one&&&two  ;
say &&&one&&&two;
[download]

It is not that difficult to figure out, it was a accidental discovery while messing around with syntax highlighting. For the friends of JAPH, here's one with five consecutive ampersands:

use 5.020;
sub s { say };
$_ = 'Jusst another Perl hacker';
s&s&&&&&s
[download]

Comment on A twisty little maze of ampersands, all different Select or Download Code

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Re: A twisty little maze of ampersands, all different
by kcott (Archbishop) on Jun 09, 2021 at 06:49 UTC

G'day haj,

++ That's very interesting. Using

perl -MO=Deparse,p -E 'sub one {1} sub two {2} say <ampersand-part>'
[download]

I get:

one&two      : say one(&two);
&one&two     : say &one & two();
&one&&&two   : say &one && &two;
&&&one&&&two : &two if say $_ and &one;
[download]

Just for completeness, each of those is preceded by:

use feature 'current_sub', 'bitwise', 'evalbytes', 'fc', 'postderef_qq
+', 'say', 'state', 'switch', 'unicode_strings', 'unicode_eval';
sub one {
    1;
}
sub two {
    2;
}
[download]

and ends with: