It does work in ipython it just is annoying to navigate and you have to rely on the automatic indenting a bit more if you are adding anything (as the ...: is missing).
Unless of course you mean history through different sessions as that doesn't work for full functions.
Indents are included with a simple up arrow with ipython, it also works if you are doing a backwards search (C-r), it just doesn't have the nice formatting you get when you first write the function.
