Re: Why does this code think I'm trying to use symbolic references?

I know how to work around it; but for the life of me I cannot see why I need to?

This is hairy. It is one case where whitespace matters in perl.

Two things are going on here:

resolution of the args to print as indirect object notation vs. resolvable term
determination of the meaning of '+' in '$n +4'

use strict; $n = 1000; $\=$/;
print $n +4;  # indirect object notation, + is sign marking 4 as posit
+ive (unary plus)
print $n + 4; # $n + 4 is addition, result is printed
print +$n +4; # unary + prevents $n from being interpreted as file han
+dle, 1004 is printed
print ($n +4); # same as case 1
print ($n + 4); # same as case 2
print+($n +4); #same as case 3
[download]

perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'

Comment on Re: Why does this code think I'm trying to use symbolic references? Download Code

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Re^2: Why does this code think I'm trying to use symbolic references? by BrowserUk (Patriarch) on Jun 13, 2016 at 12:37 UTC
This is hairy. Indeed. I'm just amazed that I have never encountered this before. I regularly hit this one: `$x = 10; print ( $x + 1 ) / 3;; 11` [download] But never to my recollection the OP problem. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :) In the absence of evidence, opinion is indistinguishable from prejudice. Not understood.	[reply] [d/l]
Re^2: Why does this code think I'm trying to use symbolic references? by Your Mother (Archbishop) on Jun 13, 2016 at 14:54 UTC
I understand it is strange to hit whitespace issues in Perl (where weirdness like `my$ n = 1` is legal) but this seems sensible and, this part, not hairy; I'd be alarmed if it worked any differently. Only the `print(list)` and file handle stuff is surprising and Perl users learn those issues, I hope, pretty early. `+4` looks, like `-4`, unambiguously signed. Maybe the negative reads more clearly since we're used to never seeing the positive. `print $n -4;`	[reply] [d/l] [select]
Re^3: Why does this code think I'm trying to use symbolic references? by shmem (Chancellor) on Jun 14, 2016 at 15:36 UTC
I understand it is strange to hit whitespace issues in Perl (where weirdness like `my$ n = 1` is legal) but this seems sensible and, this part, not hairy; I'd be alarmed if it worked any differently. Yes, yes and yes; and yes. My statement is ambiguous, too: not the implemented behaviour (which is fine) is hairy, instead I qualify the edge case itself as such. And it shows - again - how well kept and thought out/through perl is. p5p are doing an awesome job. perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'	[reply] [d/l]