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Repeat syntax
From: |
Christopher Howard |
Subject: |
Repeat syntax |
Date: |
Fri, 24 Nov 2017 20:05:26 -0900 |
Hi list, I want to have a function
(repeat n exp exp* ...)
That calls the expressions n times for side effect, like for-each, but
without the bother of dealing with a list. It seems like somebody else
must have thought of this before, but I couldn't find the equivalent
procedure. After reading 6.10.2 I came up with this
(define-syntax repeat
(syntax-rules (repeat)
((_ n exp exp* ...)
'(unless (<= n 0)
exp
exp*
...
(repeat (- n 1) exp exp* ...)))))
Which doesn't work I think because repeat gets expanded infinitely many
times. I was pondering other ways to do this, but they all seem to end
in either infinite expansion, or an important variable getting
overshadowed. So, could somebody point me in the right direction?
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- Repeat syntax,
Christopher Howard <=