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    <p>EDIT: In response to your update, I think you want to do something like this:</p> <pre><code>(eval `(define ,&lt;procedure-to-return-symbol&gt; ,&lt;value&gt;) &lt;environment&gt;) </code></pre> <p>e.g. in mit-scheme:</p> <pre><code>(eval `(define ,(string-&gt;symbol "abc") ,(* 2 2)) user-initial-environment) </code></pre> <p>Where <code>user-initial-environment</code> is the environment under which symbols are interned when typed into the REPL. This example will return the symbol <code>abc</code> associated with the value 4. Using this method you would be able to use your procedure to create the name and associate it with the value returned by my solution below. You can read more about <code>eval</code> and mit-scheme environments <a href="http://groups.csail.mit.edu/mac/ftpdir/scheme-7.4/doc-html/scheme_14.html" rel="nofollow">here</a>. <code>&lt;/edit&gt;</code></p> <p>EDIT2: An explicit solution:</p> <pre><code>(define (cxr x) (define (helper xlist arg) (cond ((null? xlist) arg) ((eq? (car xlist) #\a) (car (helper (cdr xlist) arg))) ((eq? (car xlist) #\d) (cdr (helper (cdr xlist) arg))) (else (error "INVALID ARGS FOR CXR")))) (eval `(define ,(string-&gt;symbol (string-append "c" x "r")) ,(lambda (arg) (helper (string-&gt;list x) arg))) user-initial-environment)) </code></pre> <p>In this way you can create named procedures for any depth of "ad" strings.<code>&lt;/edit&gt;</code></p> <p>Your initial solution is at best usable where there are compositions of <code>car</code> and <code>cdr</code> already defined. The problem is looking for a procedure that returns a procedure which takes the car/cdr of a list to an arbitrary depth. This is my solution:</p> <pre><code>(define (cxr x) (define (helper xlist arg) (cond ((null? xlist) arg) ((eq? (car xlist) #\a) (car (helper (cdr xlist) arg))) ((eq? (car xlist) #\d) (cdr (helper (cdr xlist) arg))) (else (error "INVALID ARGS FOR CXR")))) (lambda (arg) (helper (string-&gt;list x) arg))) </code></pre> <p><code>helper</code> runs down the list of a's and d's calling the either <code>car</code> or <code>cdr</code> on the result of the next call to <code>helper</code> -- it builds the body for the <code>lambda</code>. When the list is empty, <code>helper</code> returns <code>arg</code> which is the parameter for the <code>lambda</code> expression. Since the <code>lambda</code> form does not have an argument passed to it in the definition, <code>cxr</code> will return a procedure. </p>
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    1. POHow to pass a string as a function name in scheme ? [Dynamic construction of functions names in Scheme]
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    1. COPlease see above: i guess I ve just found the solution; - thank you ! i ve not tried your solutiuon yet, i will try it now !
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    2. COYour update doesn't appear to call `eval` correctly -- it requires an environment variable. Please see my second edit for an explicit solution.
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