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At Thu, 25 Mar 2004 21:54:09 -0500 (EST), Andre van Tonder wrote:
>
> On Fri, 26 Mar 2004, Alex Shinn wrote:
>
> > Anyway, any Scheme can trivially handle both by renaming define-syntax
> > to something like internal-define-syntax and building a new
> > define-syntax on top of that.
>
> Don't you need module support for this?
I meant at the core language level (in most cases in C) you just do a
big query/replace s/((define|let|letrec)-syntax)/internal-\1/.
The wrapper then becomes the existing reference implementation for
define-syntax-computations (in terms of internal-define-syntax) plus:
(internal-define-syntax define-syntax
(syntax-rules (syntax-computations)
;; catch syntax-computations
((_ name (syntax-computations x ...))
(define-syntax-computations name (syntax-computations x ...)))
;; manually add static checks for other cases like syntax-case
;; ...
;; default
((_ x ...)
(internal-define-syntax x ...))))
and likewise for let-syntax and letrec-syntax.
Hackish but very easy and it's only the worst-case scenario. It just
means the Scheme implementors themselves have to want SRFI-53 - end
users can't extend with an add-on module. And of course you still have
no way to dynamically add new syntax-FOOs.
--
Alex