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+(in-package :lambda-tools)
+
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (defun is-substitute-var (symbol)
+    (and (symbolp symbol)
+         (eq (elt (symbol-name symbol) 0)
+             #\_))))
+
+
+
+
+
+(defmacro $ (expr)
+"Quickly create functions from an expression EXPR with 'blanks' in
+it. Each blank is a symbol that betins with the underscore _. Symbols
+with the same name are treated as the same variable.
+
+A function is returned, it accepts exactly the number of variables as
+there were unique blanks in the expression. When calling the new
+function, the variables are bound in the order they appeared in EXPR.
+
+> (macroexpand-1 '($ (+ _a (* _b 3) _b (- _a _c) 10)))
+  (LAMBDA (_A _B _C) 
+     (+ _A 
+       (* _B 3) 
+       _B 
+       (- _A _C) 
+       10))
+
+The macro is useful for succinctly passing functions to
+higher order functions:
+
+> (mapcar ($ (+ _ 10)) '(1 2 3 4))
+ (11 12 13 14)
+
+> (let ((elt-num 2))
+    (mapcar ($ (elt _ elt-num)) 
+            (list \"hey dude\" 
+                  #(1 2 3 4)
+                  \"ffffffffff\")))
+ (#\y 3 #\f)
+"
+  (let  ((new-params (list)))
+    (subst-if t (constantly nil) expr
+              :key (lambda (x) (when (is-substitute-var x)
+                                 (pushnew x new-params))))
+    `(lambda ,(reverse  new-params) ,expr)))
+
+
+
+
+
+