[lib] Add -2map and siblings

lib/lib-advent.org

@@ -38,6 +38,7 @@
                                                (-map-indexed (lambda (x el) (list el (list x y))) l))
                                              li)))))
   #+end_src
+
 * 2D geometry auxiliary functions
   Here a vector is just a list with two components; the "dot"
   function is a bit of an overkill tbh
@@ -56,4 +57,23 @@
       "Returns the taxicab distance from P to Q"
       (+ (abs (- (car p) (car q)))
          (abs (- (cadr p) (cadr q)))))
-#+end_src
+       #+end_src
+
+  These are two-dimensional equivalent of -map and -map-indexed
+  #+begin_src emacs-lisp
+    (defun -2map (fun li)
+      (--map (-map fun it) li))
+
+    (defmacro --2map (form list)
+      `(-2map (lambda (it) ,form) ,list))
+
+    (defun -2map-indexed (fun li)
+      (-map-indexed (lambda (j row)
+                      (-map-indexed (lambda (i it)
+                                      (funcall fun i j it))
+                                    row))
+                    li))
+
+    (defmacro --2map-indexed (form li)
+      `(-2map-indexed (lambda (it-index-1 it-index-2 it) ,form) ,li))
+  #+end_src