Answers of varying lengths: 
sub interlace {  # 52
my$x=pop;my$y=reverse+pop;$x=~s/./chop($y).$&/esg;$x   
}

sub interlace {  # 47
my$x=pop;@_=split//,pop;$x=~s/./shift.$&/esg;$x   
}

sub interlace {  # 45
($_,@_)=(pop,split//,pop);s/./shift.$&/esg;$_  
}

[download]
The last two suffer a mandatory 'shift without parens' warning.

Update: here's a shorter one, without said warning. 

sub interlace {  # 43
$_=shift;@_=split//,pop;s/./$&.shift/esg;$_   
}

[download]


japhy -- Perl and Regex Hacker

In reply to Re: (golf) Interlaced Strings by japhy
in thread (golf) Interlaced Strings by yakko

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