1 files changed, 64 insertions, 3 deletions
diff --git a/_tils/2021-04-24-clojure-auto-curry.md b/_tils/2021-04-24-clojure-auto-curry.md
index 0d50cfa..c1e277f 100644
--- a/_tils/2021-04-24-clojure-auto-curry.md
+++ b/_tils/2021-04-24-clojure-auto-curry.md
@@ -4,6 +4,8 @@ title: Clojure auto curry
 
 date: 2021-04-24 1
 
+updated_at: 2021-04-27
+
 layout: post
 
 lang: en
@@ -16,11 +18,11 @@ Here's a simple macro defined by [Loretta He][lorettahe] to create Clojure funct
 
 ```clojure
 (defmacro defcurry
-  [fname args & body]
+  [name args & body]
   (let [partials (map (fn [n]
-                        `(~(subvec args 0 n) (partial ~fname ~@(take n args))))
+                        `(~(subvec args 0 n) (partial ~name ~@(take n args))))
                       (range 1 (count args)))]
-    `(defn ~fname
+    `(defn ~name
        (~args ~@body)
        ~@partials)))
 ```
@@ -72,3 +74,62 @@ Simple and elegant.
 Same Clojure as before, now with auto-currying via macros.
 
 [lorettahe]: http://lorettahe.github.io/clojure/2016/09/22/clojure-auto-curry
+
+## Comparison with Common Lisp
+
+My attempt at writing an equivalent for Common Lisp gives me:
+
+```lisp
+(defun partial (fn &rest args)
+  (lambda (&rest args2)
+    (apply fn (append args args2))))
+
+(defun curry-n (n func)
+  (cond ((< n 0) (error "Too many arguments"))
+        ((zerop n) (funcall func))
+        (t (lambda (&rest rest)
+             (curry-n (- n (length rest))
+                      (apply #'partial func rest))))))
+
+(defmacro defcurry (name args &body body)
+  `(defun ,name (&rest rest)
+     (let ((func (lambda ,args ,@body)))
+       (curry-n (- ,(length args) (length rest))
+                (apply #'partial func rest)))))
+```
+
+Without built-in multi-arity support, we have to do more work, like tracking the number of arguments consumed so far.
+We also have to write `#'partial` ourselves.
+That is, without dependending on any library, sticking to ANSI Common Lisp.
+
+The usage is pretty similar:
+
+```lisp
+* (defcurry add (a b c d e)
+    (+ a b c d e))
+ADD
+
+* (add 1)
+#<FUNCTION (LAMBDA (&REST REST) :IN CURRY-N) {100216419B}>
+
+* (funcall (add 1) 2 3 4)
+#<FUNCTION (LAMBDA (&REST REST) :IN CURRY-N) {100216537B}>
+
+* (funcall (add 1) 2 3 4 5)
+15
+
+* (funcall (funcall (add 1) 2 3) 4 5)
+15
+
+* (macroexpand-1
+    '(defcurry add (a b c d e)
+       (+ a b c d e)))
+(DEFUN ADD (&REST REST)
+  (LET ((FUNC (LAMBDA (A B C D E) (+ A B C D E))))
+    (CURRY-N (- 5 (LENGTH REST)) (APPLY #'PARTIAL FUNC REST))))
+T
+```
+
+This also require `funcall`s, since we return a `lambda` that doesn't live in the function namespace.
+
+Like the Clojure one, it doesn't support optional parameters, `&rest` rest arguments, docstrings, etc., but it also could evolve to do so.