I'll get things started here. I don't have time for the extra credit, but this solves the first part: 
sub t_in_s {
($t=pop)=~s/./$&.*/g;$_[0]=~$t
}

t_in_s('abcdefghijklmnopqrstuvwxyz', 'for');

[download]
Although, if $t may contain non-word characters, that becomes: 
sub t_in_s {
($t=pop)=~s/./\Q$&\E.*/g;$_[0]=~$t
}

[download]

In reply to Re: Golf: Embedded In Order by chipmunk
in thread Golf: Embedded In Order by Masem

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