It's not really returning "true", it's returning the value on the right side of the assignment. 

my $x = 2;
print "\$x is '$x'\n";

if ( $x = 0 ) {
    print "\$x = 0 is true\n";
}
else {
    print "\$x = 0 is false\n";
}

print "\$x is '$x'\n";
__END__
$x is '2'
$x = 0 is false
$x is '0'

[download]

This behavior is why you can say "$x = $y = $foo" and set both $x and $y to whatever is in $foo.

If you consider the "effect" of assignment to be returning the value of the right hand side, then perhaps changing the value of the variable is a side effect. I don't see it that way, however.

In reply to Re^5: map in void context by kyle
in thread map in void context by dharanivasan

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