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Re: Opaque syntax objects

On Sun, 14 Aug 2005, [ISO-8859-1] Jens Axel Søgaard wrote:

The purpose of the do-primes example was to show that simple destructuring is possible without using syntax-case.


in the case were it is neccessary to use normal Scheme operators, most
often a call to syntax->list, which turns a syntax-object representing a
list into a list of syntax-objects, is enough to solve the problem.

This can entail a rather expensive performance hit.

What is "rather expensive"?

I was referring to having to walk the expression with syntax->list to the required depth before being able to use, e.g., SRFI-1 operations on it. It may not always be expensive, but it could be.