out of curiosity. parse-long came to Clojure in 1.11. Will we get parse-long in Sci after a Clojurescript also provides the function? Then, add a line like

'juxt (copy-core-var juxt)

The problem here is that parse-long isn't available in every version of clojure, so we'd have to backport it since SCI supports clojure 1.9+. Alternatively you can just add it yourself in {:namespaces {'clojure.core {'parse-long ...}}}

Similar for clojure.math. This has been added in babashka

but not in SCI

One other concern is that everything added to namespaces will be part of the JS bundle so going forward I think I won't add anything new there if it wasn't already in 1.9-1.10 but provide ways to optionally include it

but parse-long seems small enough for that not to be a problem

Maybe we can have an optional addon namespace which provides 1.11 features and one for clojure.math too

so you can load those when you're on clojure 1.11