Vim, insert text from register on beginning of row

Question

Is there a way to tell (g)Vim to insert from register at the beginning of a row? I know I can use s/^/[text]/ but I was thinking more along the lines of :g/[text]/ "+p except that that doesn't work. I guess the problem is that there's no way for Vim to decide where to put the content of the register.

Answer 1

Here's one way:

:g/pattern/s/^/\=@a/

will insert the contents of register a at the start of every line containing pattern. See

:help sub-replace-expression
:help expr-register

Answer 2

You can use P to paste before cursor (and p to paste after).

So if you got at the beginning of a row with 0 or ^, you can they use "+P.