[r6rs-discuss] [Formal] Trivial Enhancement of macros in v5.91: capture-syntax

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The macro system needs a way of redefining core forms without losing their primitive definitions.
     Scheme is a language without reserved words.  However, while it is possible to redefine
core forms such as lambda, doing so will render the system useless, because the original
primitive transformer will be lost.  The v 5.91 draft has admitted that syntactic transformation
is accomplished by closures.  These closures should be accessible.  The following code
illustrates the idea.
(define-syntax primitive-lambda (capture-syntax lambda))
(define-syntax lambda (capture-syntax trace-lambda))
<code to be traced>
(define-syntax lambda (capture-syntax primitive-lambda))
A more serious example might extend the definition of lambda to take keyword arguments or
more patterns in the argument than a simple list.  The capture-syntax form should be trivial
to implement.
Lynn Winebarger