Hello Emmanuel, really nice to see you here !
A few smallish comments on your code (I'll try to build it later) You mixed tabs & spaces for indentation. Looks like the second lambda does not return #t, if I'm not mistaken the return value will be setenv's which is unspecified. I'll try to be more helpful in my next reply ;-) And sorry if my answer broke the threading, I just subscribed... -- Vincent Legoll