<div dir="ltr"><div dir="ltr">Thanks for the fast reply. One thing I don't understand: 'exp' is bounded without scheme/base. What is so special about the new binding in scheme/base? For example, the following code works fine: (define foo (lambda (x) (* x x))) (define foo (lambda (b e) (if (= e 0) 1 (* b (foo b (- e 1)))))) (foo 2 5) I bind foo twice with different parameters, but its working! </div> <div class="gmail_quote">On Tue, Mar 8, 2011 at 2:50 PM, Sam Tobin-Hochstadt <<a href="mailto:samth@ccs.neu.edu">samth@ccs.neu.edu</a>> wrote: <blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"> `scheme/base' provides a binding called `exp', which requires 2 arguments. When the compiler expands your definition, it looks at the variable reference in the body of the function *before* it binds your new `exp' definition. Therefore, it uses the `exp' that it has in scope at that time -- the one from `scheme/base'. This is an instance of a general problem with compilation and expansion at the top-level, and one of the many reasons why it's better to write programs in modules. <div><div></div><div class="h5"> On Tue, Mar 8, 2011 at 7:37 AM, Yaron Gonen <<a href="mailto:yaron.gonen@gmail.com">yaron.gonen@gmail.com</a>> wrote: > Hi, > (I'm using Dr Scheme version 4.2.2, with language R5RS, and the "Disallow > redefining" is not checked.) > > The following code works perfectly: > (define exp > (lambda (b e) > (if (= e 0) 1 > (* b (exp b (- e 1)))))) > (exp 2 5) > > However, when I include the line (#%require scheme/base), I get an error: > exp: expects 1 argument, given 2: 2 4 > > How is that possible? > > Many thanks, > Yaron > </div></div>> _________________________________________________ > For list-related administrative tasks: > <a href="http://lists.racket-lang.org/listinfo/users" target="_blank">http://lists.racket-lang.org/listinfo/users</a> > -- sam th <a href="mailto:samth@ccs.neu.edu">samth@ccs.neu.edu</a> </blockquote></div> </div>