"Profiling" my startup scripts

["Daniel Serodio (lists)" <daniel.lists@xxxxxxxxxxxxx>]

I have somewhat complex .zshrc and .zshenv startup scripts that I've 
improved over the years, running Linux. Now I'm using OSX and something 
in these scripts is taking more time than usual, and I'd like to 
"profile" them, ie. find out how long each step takes.

My first idea was to add a $(date) execution to PS4, but I found that it 
doesn't work in zsh (it works in bash).

Do you have any suggestions about a better way to profile my startup 
scripts?

Also, would you add this feature (command execution substitution in PS4) 
to zsh?

Thanks in advance,
Daniel Serodio