del

beautiful-racket-demo/basic-demo-3/for.rkt

@@ -1,30 +0,0 @@
-#lang br
-(require "misc.rkt" "line.rkt")
-(provide b-for b-next)
-
-(define thunk-table (make-hasheq))
-
-(define-macro-cases b-for
-  [(_ LOOP-ID START END) #'(b-for LOOP-ID START END 1)]
-  [(_ LOOP-ID START END STEP)
-   #'(b-let LOOP-ID (let/cc loop-cc
-                      (hash-set! thunk-table
-                                 'LOOP-ID
-                                 (λ ()
-                                   (define next-val (+ LOOP-ID STEP))
-                                   (if (next-val . in-closed-interval? . START END)
-                                       (loop-cc next-val)
-                                       (hash-remove! thunk-table 'LOOP-ID))))
-                      START))])
-
-(define (in-closed-interval? x start end)
-  (if (< start end)
-      (<= start x end)
-      (<= end x start)))
-
-(define-macro (b-next LOOP-ID)
-  #'(begin
-      (unless (hash-has-key? thunk-table 'LOOP-ID)
-        (raise-line-error "next without for"))
-      (define thunk (hash-ref thunk-table 'LOOP-ID))
-      (thunk)))