in reply to Re: Inserting an element into an array after a certain element
in thread Inserting an element into an array after a certain element

I still don't think you should insert if the elment you specify isn't there.
sub insert_after_first { my ($element, $insert, @array) = @_; my $hit; map {($_, ($_ eq $element and !$hit++) ? $insert : ())} @arr; }

Caution: Contents may have been coded under pressure.