This reminds me of what a classmate of mine is working on for his PhD: http://www.sable.mcgill.ca/~cpicke/papers/pickett-09-softwar...

Is there an equivalent to history-search-backward in zsh? In Bash, this is the search that looks for commands that start with whatever is to the left of the cursor.

add this to your .zshrc:

bindkey '^r' history-incremental-search-backward

I suggest to look for a .zshrc file, the article has a good one linked.