On 09/17/2012 02:20 PM, John Clements wrote:
On Sep 16, 2012, at 5:48 PM, Ryan Culpepper wrote:
See 'define-template-metafunction' in syntax/parse/experimental/template.
Remember to change the relevant occurrences of 'syntax' to 'template'.
Neat!
I'm guessing, though, that I probably shouldn't release planet packages that
depend on experimental-mumble…
I think it's fine if you're prepared to update the package when it
changes. If I do remove syntax/parse/experimental/template, I'll mark it
as deprecated for a release cycle or two first.
Ryan
On 09/16/2012 08:31 PM, John Clements wrote:
I want to apply a transformation to a nested pattern element.
To start with, suppose I have a (kind of useless) with-handlers that looks like
this:
(with-syntax
([((arg ...) ...)
#`((clause.input ...) ...)])
et-cetera)
That is, I've basically just renamed "clause.input" to "arg".
But now, I want to perform some transformation on the elements. I'd like to
write this:
(with-syntax
([((arg ...) ...)
#`((#,(transform #'clause.input) ...) ...)])
et-cetera)
.. but this fails, with the error "new-style-signals.rkt:42:30: syntax: missing
ellipsis with pattern variable in template in: clause.input"
I can certainly work around this, by abandoning the pattern-matching slickness and
just using a bunch of syntax->lists, but it seems like there must be a nicer
way. Am I missing some nifty trick?
John
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