From 6ad59477cd0540cfe466117c03af7311c1e40440 Mon Sep 17 00:00:00 2001 From: Matthew Butterick Date: Fri, 3 Jun 2016 22:29:19 -0700 Subject: [PATCH] nits --- beautiful-racket/br/demo/basic/aceyducey.bas | 2 +- beautiful-racket/br/demo/basic/expander.rkt | 23 +++++++++----------- 2 files changed, 11 insertions(+), 14 deletions(-) diff --git a/beautiful-racket/br/demo/basic/aceyducey.bas b/beautiful-racket/br/demo/basic/aceyducey.bas index e0ffee9..c9a09fd 100644 --- a/beautiful-racket/br/demo/basic/aceyducey.bas +++ b/beautiful-racket/br/demo/basic/aceyducey.bas @@ -11,7 +11,7 @@ 80 PRINT"IF YOU DO NOT WANT TO BET, INPUT A 0" 100 N=100 110 Q=100 -120 PRINT "YOU NOW HAVE";Q;"DOLLARS." +120 PRINT "YOU NOW HAVE ";Q;" DOLLARS." 130 PRINT 140 GOTO 260 210 Q=Q+M diff --git a/beautiful-racket/br/demo/basic/expander.rkt b/beautiful-racket/br/demo/basic/expander.rkt index e8bac18..5295ff5 100644 --- a/beautiful-racket/br/demo/basic/expander.rkt +++ b/beautiful-racket/br/demo/basic/expander.rkt @@ -66,7 +66,7 @@ (set! return-stack (cons return-k return-stack)) (basic:goto where))) -(struct $line (number thunk) #:transparent) +(struct $line (number thunk)) (define-macro (line NUMBER . STATEMENTS) #'($line NUMBER (λ () (with-handlers ([end-line-signal? (λ _ #f)]) . STATEMENTS)))) @@ -168,19 +168,16 @@ #'(basic:for VAR START-VALUE END-VALUE 1)] [(_ VAR START-VALUE END-VALUE STEP-VALUE) #'(begin - ;; initialize the loop counter - (statement VAR "=" START-VALUE) - ;; create a point for the `next` statement to return to, using a continuation - (let/cc return-point-for-next + (statement VAR "=" START-VALUE) ; initialize the loop counter + (let/cc return-k ; create a return point (push-for-stack (cons 'VAR - (procedure-rename - (λ () ; thunk that increments counter & teleports back to beginning of loop - (define next-val (+ VAR STEP-VALUE)) - (if (<= next-val END-VALUE) - (begin - (set! VAR next-val) - (return-point-for-next #f)) ; return value for subsequent visits to line - (pop-for-stack))) (format-datum "~a-incrementer" 'VAR)))) + (λ () ; thunk that increments counter & teleports back to beginning of loop + (define next-val (+ VAR STEP-VALUE)) + (if (<= next-val END-VALUE) + (begin + (set! VAR next-val) + (return-k #f)) ; return value for subsequent visits to line + (pop-for-stack))))) #f))]) ; return value for first visit to line (define (handle-next [which #f])