15 lines
385 B
Janet
15 lines
385 B
Janet
(defn diff [expr var]
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(cond
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(symbol? expr) (if (= expr var) 1 0)
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(number? expr) 0
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(match expr
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[op & args] (case op
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'+ ['+ ;(map |(diff $ var) args)]
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'* (let [[a b] args]
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['+ ['* (diff a var) b]
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['* a (diff b var)]])
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(errorf "unknown op: %v" op)))))
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(pp (diff '(+ (* x x) 3) 'x))
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(pp (diff '(+ x 3) 'x))
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