Re: Thoughts on using and, or, and not over && || !?

Hello Argel,

In addition to the potential predecence problems with or, it should be noted that Perl’s // (Logical Defined-Or) operator has no low-precedence equivalent, so if you get in the habit of using or in place of ||, you may more easily overlook situations in which // is a better fit:

13:09 >perl -Mstrict -wE "my ($y, $z); my $x = (defined $y or defined 
+$z or 'default'); say $x;"
default
[download]

vs.

13:09 >perl -Mstrict -wE "my ($y, $z); my $x = $y // $z // 'default'; 
+say $x;"
default

13:09 >
[download]

As a rule I use and and or for flow control only:

open(my $fh, '<', $filename) or die "Cannot open file '$filename' for 
+reading: $!";
[download]

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

Comment on Re: Thoughts on using and, or, and not over && \|\| !? Select or Download Code

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Re^2: Thoughts on using and, or, and not over && \|\| !? by Marshall (Canon) on Jul 12, 2016 at 06:59 UTC
Good post++. I would just add that the //= version of this operator is also available. `my $xyz; $xyz //= 'default'; print $xyz; #default` [download]	[reply] [d/l]
Re^2: Thoughts on using and, or, and not over && \|\| !? by ikegami (Patriarch) on Jul 17, 2016 at 21:06 UTC
In addition to the potential predecence problems with or, Depends on context. While `or` is more likely to cause problems within an expression (aside from not being as visually distinctive), `or` is usually used for flow control because it's more likely to solve precedence problems in that situation. Compare `open my $fh, '<', $qfn \|\| die $!;` [download] with `open my $fh, '<', $qfn or die $!;` [download]	[reply] [d/l] [select]