java - Clojure doto macro -


i going call .touppercase method within doto macro follows doto returns small letters:

(doto (java.lang.string. "clojure")        (.touppercase))

returns "clojure". macroexpansion , return value object created: (clojure.core/let [g__7359 (java.lang.string. "cojure")] (.touppercase g__7359) g__7359) , why don't uppercased answer?

doto part of clojure's java interop features. designed make possible write java out soooo darn many parens. so

foo foo = new foo; foo.setx().sety().makefactory().applyphaseofmoon();

which has 8 parens becomes:

(doto foo .sety .makefactory .applyphaseofmoon)

which has total of two.

in case if dig expanstion of example:

user> (doto "hi" .touppercase) "hi"

expands to: 

user> (macroexpand-1 '(doto "hi" .touppercase)) (clojure.core/let [g__110453 "hi"]    (.touppercase g__110453)     g__110453)

where second line this:

user> (.touppercase "hi") "hi"

and throws answer away , returns saved value form start. never see doto used in practice outside of places people translating java clojure inorder call api.


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