Re: Question on HtDP

[Jeffrey Stephens <jsteve17@tampabay.rr.com>]

Thanks for the info.  I wasn't trying to use mzscheme in a big way.  For some
reason, and I forget why now, I was trying the symbol=? construct in mzscheme
and got an error. It was then that I discovered you had to first execute
"(require (lib "etc.ss))".  That got me to wondering whether symbol=? was
really a part of the language.  Up to this point I had assumed everything in
HtDP was a part of the R5RS definition of Scheme.  Does Scheme have the concept
of a Standard Library like C/C++?  Would one find symbol=? in other
implementations of Scheme, e.g., mitscheme or chez scheme?

Regards,
Jeff Stephens

On Wed, 24 Oct 2001, Matthias Felleisen wrote:
> Yes, HtDP is incorrect in a number of claims of this form. 
> What is meant with these statements is 
>  
>  "The Scheme language level that you should be using 
>   has only one primitive for dealing with symbols: symbol=?." 
> 
> They should all be rewritten, but I thought that this was too 
> complicated. 
> 
> The require mechanism provides a good way for making drscheme
> programs run in mzscheme. Indeed, you shouldn't know about this 
> either. Just built launchers if you wish to produce "standalone"
> programs from your drscheme functions. (Not totally easy but doable.) 
> 
> -- Matthias