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    <pre><code>(define (term-expander n val partial) (if (zero? n) partial (term-expander (- n 1) val (cons val partial)))) (define (append-expand a b) (if (pair? b) (append a (term-expander (car b) (cadr b) '())) (append a (list b)))) (define (expand l) (foldl append-expand l '() )) &gt; (expand '(a (3 b) (3 a) b (2 c) (3 a))) (a b b b a a a b c c a a a) </code></pre> <p>So... <code>term-expander</code> takes <code>(5 a)</code> -> <code>'(a a a a a)'</code>. <code>append-expand</code> will append the newest term (expanded iff it is a pair) to our answer in progress. just need to fold this over the list.</p> <p>I'd hope you have a <code>foldl</code> already, but heres mine just in case.</p> <pre><code>(define (foldl op seq init) (define (iter acc rest) (if (null? rest) acc (iter (op acc (car rest)) (cdr rest)))) (iter init seq)) </code></pre> <hr> <h2>EDIT</h2> <p>Realized afterwards this is can be done a LITTLE bit more naturally with <code>foldr</code> rather than <code>foldl</code> (will need <code>append-expand</code> written differently). Why don't you see if you can find it? Same idea mostly, but it will operate on the list from back to front and lends itself more naturally to <code>cons</code> structures</p> <hr> <p>Here's me doing it without fold, but it works the same way and i dont really care for it</p> <pre><code>(define (term-expander p partial) (if (zero? (car p)) partial (term-expander (cons (- (car p) 1) (cdr p)) (cons (cadr p) partial)))) (define (expand l) (define (expand-rec l partial) (if (null? l) partial (let ((t (if (pair? (car l)) (term-expander (car l) '()) (list (car l))))) (expand-rec (cdr l) (append partial t))))) (expand-rec l '())) &gt; (expand '(a (3 b) (3 a) b (2 c) (3 a))) (a b bb a a a b c c a a a) </code></pre> <p>If you would prefer, the <code>(if (pair?...</code> section could go in to <code>term-expander</code> instead, and then you'd just call it across the board. I slightly prefer this way but its all the same</p>
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    1. POscheme expand function
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    1. COIs there a way to do this without using higher order functions?
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    2. COsure, but you'll really just be doing the equivalent of it. if you choose to do it that way it will probably come more naturally if you put that `(if (pair?...` stuff into `term-expander`
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    3. COactually scratch that. i would only call it on pairs to begin with
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