I found out (much to my surprise) that join MUST enclose its arguments in parens if it is used in a statement with concatenations. Is this normal behavior for join, or is this a bug? The sample code below shows the effect: 

#!/usr/bin/perl
use strict;
use warnings;

my @array = qw( a b c );

print "\nSimple join (without parens) - OK\n";
my $cols  = join('],[',@array);
print "cols = $cols\n";

print "\nConcatenation and join (without parens)- NOT OK\n";
$cols  = '[' . join '],[',@array . ']';
print "cols = $cols\n";

print "\nConcatenation and join (with parens) - OK\n";
$cols  = '[' . join('],[',@array) . ']';
print "cols = $cols\n";

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In reply to Join and Concatenation by roho

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