implement diff

2026-06-21 19:49:19 +02:00
parent 3ce79efaa1
commit b6779a930c
1 changed files with 14 additions and 0 deletions
@@ -0,0 +1,14 @@
+(defn diff [expr var]
+  (cond
+    (symbol? expr) (if (= expr var) 1 0)
+    (number? expr) 0
+    (match expr
+      [op & args] (case op
+        '+ ['+ ;(map |(diff $ var) args)]
+        '* (let [[a b] args]
+             ['+ ['* (diff a var) b]
+                        ['* a (diff b var)]])
+        (errorf "unknown op: %v" op)))))
+
+(pp (diff '(+ (* x x) 3) 'x))
+(pp (diff '(+ x 3) 'x))