Disclaimer: I do not make decisions on what gets into clojure.core.
Here is a page that gives some reasons why most things don't get into
clojure.core:
http://dev.clojure.org/display/design/Why+Feature+X+Was+Declined
More specifically on if-all-let and things like it, many people seem to
disagree
(defmacro if-all-let [bindings then else]
(reduce (fn [subform binding]
`(if-let [~@binding] ~subform ~else))
then (reverse (partition 2 bindings
I quoted the function from p259 of "Chas Emerick, Brian Carper, Christophe
Grand-Clojure Programming-O'Reilly Media (2012)"
