#!/usr/bin/perl
use strict;
use feature qw{ say };
use warnings;

use JSON::PP;

my $json = "{'k1':'v1','k2':'v2'}";
decode_json($json);
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Error:

unexpected end of string while parsing JSON string, at character offse
+t 2 (before "k1':'v1','k2':'v2'}")
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JSON::XS gives even more informative message:

'"' expected, at character offset 1 (before "'k1':'v1','k2':'v2'}")
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JSON understands double quotes only:

'{"k1":"v1","k2":"v2"}'
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($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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