So I've discovered that a common task for me in Vim is to PUT either to the start of the line or the end of the line. So my mapping could be:
nmap <Leader>p $p
nmap <Leader>P 0P
However, what I'd really like to do is optionally include a register before putting.
So for example "a,P would put from register a to the beginning of the line.
Is there a way do this with a mapping?