add damn4.rkt

[lambda.git] / damn4.rkt

diff --git a/damn4.rkt b/damn4.rkt
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+#lang racket
+
+; thanks to Ken!
+
+(let ((pragma
+       ; An ordered pair whose first component is the assertion
+       ; operator, a unary function, and whose second component
+       ; is the meaning of "damn", a thunk.
+       (call-with-current-continuation
+        (lambda (k)
+          (cons (lambda (prop) prop)
+                (lambda () (k (cons (lambda (prop) (list 'bad prop))
+                                    (lambda () 'id)))))))))
+  (let ((assert (car pragma))
+        (damn   (cdr pragma)))
+    (assert (list 'the 'student 'read 'the (damn) 'book))))
+