Ya, this has been completely fixed. There's now fully lazy as well as fully strict variants of all sequence functions. What you want to look into are transduc

Ya, this has been completely fixed. There's now fully lazy as well as fully strict variants of all sequence functions. What you want to look into are transducers: https://clojure.org/reference/transducers https://clojure.org/reference/transducers Also, the lazy operations were made batching. So they are better optimized now in memory and performance.