I stumbled on some code at work today that caused me to pull a face: 

$fred == 42 ? $config = 'k1' : $config = 'k2';

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Clearly the intent was: 
my $config = $fred == 42 ? 'k1' : 'k2';

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Yet I was surprised that the code compiled without a syntax error. The following test program illustrates: 

# weird1.pl
use strict;
use warnings;
my $config;
my $fred = shift;
print "fred='$fred'\n";
$fred == 42 ? $config = 'k1' : $config = 'k2';
print "config='$config'\n";

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Running: 
perl weird1.pl 42

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produces: 
fred='42'
config='k2'

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Running: 
perl weird1.pl 69

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produces: 
fred='69'
config='k2'

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That is, $config is always set to k2. Can anyone explain what is going on? That is, how is Perl parsing: 
$fred == 42 ? $config = 'k1' : $config = 'k2';

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Running this line of code through MO=Deparse produced the same output.

In reply to Surprised by Perl parse of ternary operator by eyepopslikeamosquito

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